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GOVERNMENT OF INDIA
MINISTRY OF RAILWAYS
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SPECIFICATION FOR 3 PHASE AC SMALL MOTORS WITH
BUILT IN INDIVIDUAL INVERTER FOR DIESEL ELECTRIC
LOCOMOTIVES
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SPECIFICATION No. MP-0.24.00.20
JULY 2008 (REVISION -01)
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RESEARCH DESIGNS & STANDARDS ORGANISATION
MANAK NAGAR, LUCKNOW-226 011
Specification no-MP-0.24.00.20 July 2008 Rev 01
SPECIFICATION FOR 3 PHASE AC SMALL MOTORS WITH BUILT IN
INDIVIDUAL INVERTER FOR DIESEL ELECTRIC LOCOMOTIVES
0.0 FOREWORD
0.1 At present, DC Fuel pump motor, DC Crank case motor, DC cyclonic filter dust
exhauster blower motor and DC rectifier blower motor (referred as small motors) are
being used as coupled to the fuel & governor pump, crank case blower, cyclonic filter
blower and rectifier blower on WDM2,WDG2,WDP2 & WDM2C diesel-electric
locomotive. The power for these motors is obtained from 72+1 V control voltage fed
by aux. generator/voltage regulator or from 64V battery. The DC motor requires
excessive maintenance because of commutation and the reliability is also very poor.
0.2 This specification is intended to serve as a guide line for the development of
individual inverter driven AC Fuel Pump Motor, AC Crank Case Motor, AC Cyclonic
filter dust exhauster blower motor and AC Rectifier blower motor for use on diesel
electric locomotives on Indian Railways.
0.3 RDSO may permit any deviation considered an improvement over existing
specification with a view to avoid any failures and reduced maintenance and to
improve the reliability of motors.
1.0 SCOPE
1.1 This specification covers the requirements of design, manufacture, testing and supply
of 3φ AC Fuel pump motor, AC Crank case motor, AC cyclonic filter dust exhauster
blower motor and AC blower motor for rectifier cooling with built in individual
inverter.
1.2 Each locomotive is equipped with one fuel pump motor, one crank case motor, two
cyclonic filter dust exhauster blower motor and one rectifier blower motor. Purchaser
can purchase these motors with inverter separately or as a full loco set.
1.3 The blower fans shall also be supplied along with the Crank case motor, Cyclonic
filter dust exhauster blower motor and Rectifier blower motor.
2.0 TERMINOLOGY
For the purpose of this specification , the following definitions shall apply:2.1 Input Voltage: The DC voltage which is applied across the input terminals of the
inverter.
2.2 Out put Voltage: The AC voltage available across the out put terminals of the
inverter.
2.3 Rated Voltage Range: It is the range of input voltage over which the inverter will
operate satisfactorily.
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Specification no-MP-0.24.00.20 July 2008 Rev 01
2.4 Rated Voltage: It is the voltage to which all the inverter characteristics are designed .
2.5 Inverter: It is an assembly comprising of semi conductor and associated electronic
and electrical components used for DC to AC inversion for the purpose of driving AC
motor which include circuit for stabilised power output, surge suppression and other
protective circuits adopted by the manufacturers for ensuring satisfactory
performance and reliability of the inverter unit.
2.6 AC Fuel Pump Motor: It is the 3 phase AC motor to be used as a driver for fuel
booster pump and governor pump.
2.7 AC Crank Case Motor: It is the 3 phase AC motor to be used as a driver for the crank
case blower fan.
2.8 AC Cyclonic filter dust exhauster blower motor: It is the 3 phase AC motor to be used
as a driver for cyclonic filter blower fan .
2.9 AC Rectifier Blower Motor: It is the 3 phase AC motor to be used as a driver for
rectifier blower fan.
3.0 SERVICE CONDITIONS
3.1 The equipment shall operate satisfactorily under the following climatic conditions.
a) Variation of ambient temp. from 0 deg. C to 55 deg. C with 100% relative
humidity.
b) Heavy rainfall with thunder storms.
c) Dusty and corrosive atmosphere with dust content in air upto 1.6 mg/m
cube.
d) Altitude –1200 m above MSL.
e) The equipment shall be designed to work in coastal area in humid salt
laden corrosive atmosphere having max. PH Value of 8.5, Sulphate 7
mg/litre and max. concentration of chlorine 6 mg/litre.
3.2 The equipment shall withstand satisfactorily
encountered in service as indicated below:
a) Max. vertical acceleration
b) Max. lateral acceleration
c) Max. longitudinal acceleration
4.0
CONSTRUCTIONAL FEATURES:
4.1
GENERAL
the vibrations and shocks normally
=
=
=
3.0 g.
3.0 g.
3.0 g.
4.1.1 The tenderer shall submit the drawing showing overall dimensions as well as
mounting dimensions.
4.1.2 The mechanical construction of the motors with built in inverter shall be such that
they can be retrofitted on the existing brackets on present locations in locos. These
motors should be matched mechanically as far as practicable with the existing DC
motors.
2
Specification no-MP-0.24.00.20 July 2008 Rev 01
4.1.3 Motor with inverter shall not infringe with any components when mounted at its
existing location on the diesel locomotives and can be directly connected with the
existing wiring without any change required.
4.2
INVERTER
4.2.1 The inverter shall be built in with respective motors. They shall be of rugged
construction.
4.2.2 The equipment shall be hose proof and tested in accordance with IS 4691. The
degree of protection shall be IP 65.
4.2.3 For dissipation of heat from the power components, a suitable design of heat sink
fins shall be provided. The heat sink should be so located as to reject heat outside
directly. The heat sink shall be designed for natural ventilation.
4.2.4 Fasteners used in inverter shall be cadmium plated and passivated according to
IS:1572. The fasteners shall conform to IS:1364.
4.2.5 The metallic frame of the inverter shall be fabricated from cold rolled annealed
steel sheet of 1.6 mm thickness conforming to IS:513.
4.2.6 The wiring used in the inverter shall conform to highest standards of current
engineering practices. All cables and wires used for wiring shall be of copper
multi-strand having PTFE insulation of adequate size and neatly secured in
position. Elastomeric insulated cables will be used for sizes for which PTFE cables
are not available. All the terminations shall be made through crimped eyelets and
diagram to be furnished by the supplier. Printed circuit cards specifically designed
to suit the circuitry used having plug in arrangement shall be used. Microprocessor
based circuits shall be preferred.
4.2.7 The components and assembly of the unit shall conform to RDSO’s reliability
specification E-16/1. The use of electrolytic capacitor shall be avoided to the
extent possible in design of the inverter.
4.2.8 The detailed specification of all the power switching devices used along with their
test certificates shall be given to RDSO. These devices should be of internationally
reputed device manufacturer. Only IGBT /MOSFET type of device shall be used.
4.2.9 Terminals of adequate size shall be provided for input and out put side with
distinct identification marks.
4.2.10 The colour of the housing of the inverter shall be finished as in the colour code No.
693 air craft gray of IS:5 “Colour for ready mixed paint”. The fins for heat sinks of
inverter may be black anodised.
4.2.11 Motor switching ON shall be done through DC circuit breaker. Inverter shall be
designed to ramp the current and voltage at the time of switching ON to take care
of the excess drawal of current and consequent drop of voltage.
4.3
AC MOTORS
4.3.1 All the motors are industrial type, squirrel cage induction motors and due care for
starting and operating current at minimum/maximum voltage and current limit
shall be taken under normal, abnormal, and fault conditions.
4.3.2 The degree of protection for motor enclosure as per IS:4691/IEC 34-5 shall be IP
54.
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Specification no-MP-0.24.00.20 July 2008 Rev 01
4.3.3 Stator construction - The stator winding shall be suitably strengthened
mechanically and vacuum pressure impregnated with insulating resin to resist the
effect of vibration, lubrication, oil fumes, diesel fumes, dust and moisture.
4.3.4 Rotor construction - Dynamically balanced pressure die cast aluminium alloy shall
be used.
4.3.5 Shaft- The material of shaft shall be EN 24 suitably heat treated to achieve
improved hardness to avoid wear & tear in service.
4.3.6 Bearing- Sealed bearing with high temperature grease should be adopted to assure
minimum maintenance and long life. These bearing should be imported SKF/FAG
of European origin or NSK/Japan. The bearing design shall have the following
features:4.3.6.1 In addition to provisions of required interface/tolerances on bearing housing, the
floating side of the bearing should be suitably preloaded.
4.3.6.2 The minimum L10 life of bearing shall be 100,000 hours.
4.3.7 Winding wires- Dual coated enameled winding wires as per IS-13730 part 13/1993
shall be used. Dual coat means base coat with polyesterimide enamel MT 533.39A
/TR 543.38 and top coat with Allotherm 602L-35S or 602L-31S of Doctor Beck &
Co.
4.3.8 The test on winding wires shall be conducted as per IS 13778 Part 1 to 6 and IS :
13730-13. Separate documentation for these test shall be maintained by the
manufacturers, indicating the winding wire supply particulars. Kapton covered
enameled winding wire conforming to IS: 11395 may also be used.
4.3.9 Impregnation- Vacuum pressure impregnation (VPI) process shall preferable be
adopted with Schenectay Beck India’s solventless unsaturated polystermide
impregnating resin Dobeckan FT 2005/500 EK.
4.3.10 The winding shall be subjected to pressure impregnation as per recommended
procedure of varnish manufacturer.
4.3.11 Slot/Interphase insulation- Calendared Nomex 410-Kapton-Calendered Nomex
410 i.e. NKN or Nomex 418 sheet shall be used for slot liner and wedge separator.
Uncalendared Nomex (Nomex 411)-Kapton-Nomex 411 sheet shall be used for
inter layer and inter phase insulation. The tenderer shall state in his offer the brand
names of insulating materials proposed to be used. The material used and
insulation system as a whole shall correspond to ‘H’ class insulation .
4.3.12 The various components of the motor shall be manufactured with such a tolerance
so as to enable complete interchangeability of components from one motor to
another of same design
4.3.13 The motor shall be treated suitably for rust and coated with antirust primer and
finished with two coats of battleship gray paints.
5.0
APPLICABLE STANDARDS/ SPECIFICATIONS
IEC-571-1, IEC 34-5, IEC349-2, IS-4691, IS-1572, IS-513, IS-5,IS-1364,IS4029,IS-13730 pt13, IS-13778 pt 1to 6, RDSO’s reliability specification E-16/1.
4
Specification no-MP-0.24.00.20 July 2008 Rev 01
6.0
EQUIPMENT TECHNICAL REQUIREMENTS OF FUEL PUMP MOTOR
WITH BUILT IN INVERTER
6.1 INVERTER6.1.1 The inverter shall meet the following requirements:6.1.2 Input Voltage (Rated)
: 72 V DC
6.1.3 Input Voltage Range
: 50 V to 90 V DC with 15% ripple. Effect of
inverter switching on input DC should not
cause ripple current more than 5% at full
load. 70% torque should be delivered at 17V
DC input voltage. During cranking of loco
voltage may dip to 17 V for a short duration.
Inverter should not trip during this duration.
The input to the AC inverter may be taken
directly from the 72 Volt DC battery supply
or 72 Volt battery supply can be suitably
increased by a DC chopper and then fed in to
the inverter.
6.14 Out put of Inverter
: 3 φ AC
6.1.5 Out put wave form
: PWM sine wave.
6.1.6 Out put frequency
: 60 Hz+2 Hz in input voltage range 65V to 90
V DC under steady state. V/f control to be
provided for constant torque operation below
65V DC input
6.1.7 Output power
: 1.5HP ( Continuous)
6.1.8 Load Power Factor
: Expected power factor > 0.8 at rated load
6.1.9 Protection
: a) Input under voltage protection (auto reset).
b) Input over voltage (auto reset).
c) Output over load (power on reset).
d) Short circuit (power on reset).
e) Reverse polarity (auto reset).
6.1.10 Cooling
: Natural self cooled.
6.1.11 Short time rating
:Manufacturer shall submit its short time
rating for 10 sec duration. This should not be
less than 150%.
6.1.12 Input over voltage protection
: set at 100 V DC input
6.1.13 Output over load protection
: set at 1.5 times the rated current
6.1.14 Reverse polarity
: Suitable protection to avoid any
damage/adverse effect to the inverter motor
set against positive and negative terminals
connected in reverse polarity shall be
provided.
6.1.15 Control mode
: PWM with V/f control
6.1.16 Internal power supply
: Wide range SM PS
5
Specification no-MP-0.24.00.20 July 2008 Rev 01
6.1.17 Power circuit configuration
6.1.18 Control circuit
:3 phase full bridge with ultra fast IGBT/Mosfet.
:Micro processor/controller based waveform
generator.
6.1.19 Harmonic distortion level at full load: less than 5% upto 20th harmonic (upto 1000
hz) on current
6.1.20 Efficiency
: Shall not be less than 90% at rated input and
rated load.
6.1.21 Negative Common electrical system exists on diesel electric locomotive.
6.1.22 Fitment – Inverter shall be fitted directly on the motor.
6.2 AC FUEL PUMP MOTOR6.2.1 Quantity
6.2.2 Rating
6.2.3 Frequency
6.2.4 Synchronous speed
6.2.5 Slip
6.2.6 Actual speed (RPM)
6.2.7 Cooling arrangement
6.2.8 Insulation
6.2.9 Starting
6.2.10 Ambient temp.
6.2.11 Type of Winding
6.2.12 No. of poles
6.2.13 Load Power Factor
6.2.14 Mech. Construction
6.2.15 Short time rating
6.2.16 Efficiency
6.2.17 Direction of rotation
: One no, 3 φ AC motor
: 1.5 HP. Continuous
: 60 Hz + 2 Hz.
: 1800 RPM at 72 V DC input voltage.
: Slip at rated output should be between 34%.
:1728 RPM (at 4% slip)
: Self cooled
: Class H
: On load
: 55 deg. C.
: 3 phase Delta/Star
: 4 poles
: > 0.8
: The mechanical construction of AC motor
shall be such that it can be readily fitted on
the existing brackets and shall be able to
adopt existing fuel pump and governor oil
pump on either end of the motor. The motor
with inverter should not
have any
infringement in its existing location on the
locomotive. The existing DC motor outline
is as per DLW drg no-AM/003
:Manufacturer shall submit its short time
rating for 10 sec duration. This should not
be less than 150%.
:The over all efficiency of the AC Motor
and inverter set should not be less than 80%
at full load . The tenderer should indicate
the overall efficiency of
the motor and
inverter set
:When connected with the correct polarity,
the direction of rotation of the motor shall
be same as that of existing DC motor
6
Specification no-MP-0.24.00.20 July 2008 Rev 01
6.2.18 Vibration level
7.0
:The vibration level on any part of the motor
shall not exceed 15 microns peak to peak.
EQUIPMENT TECHNICAL REQUIREMENTS OF CRANK CASE MOTOR
WITH BUILT IN INVERTER
7.1 INVERTER- The inverter specification shall be same as that of inverter for fuel pump
motor except the following7.1.1 Input to inverter
: Input voltage range 65V to 90 V DC under
steady state . V/f control to be provided
for constant torque operation below 65V
DC input
7.1.2 Out put frequency
7.1.3 Out put power
7.1.4 Fitment
: No exact value fixed. To be indicated in
Manufacturer data sheet.
: 0.5 HP (continuous)
: Inverter shall be directly fitted on the AC
crank case exhauster motor.
7.2 AC CRANK CASE EXHAUSTER MOTOR- The motor specification shall be
same as that of motor for fuel pump except the following7.2.1 Rating
: 0.5HP (continuous)
7.2.2 Out put of Inverter
: 3 φ AC
7.2.3 Frequency
: No exact value fixed. To be indicated in
Manufacturer data sheet.
7.2.4 Synchronous speed
: Not more then 3500 RPM at rated voltage
72 V DC.
7.2.5 Actual speed (RPM)
: To be indicated in Manufacturer data sheet.
(at 4% slip)
7.2.6 Number of poles
: 2
7.2.7Mech. Construction
: The mechanical construction of AC motor
shall be such that it can be readily fitted
on the existing brackets and shall be able
to adopt crank case exhauster blower fan
on one end of the motor. The motor with
inverter should not have any infringement
in its existing location on the locomotive.
The existing DC motor is as per DLW
drg no-EL/PT/0151.
7.2.8 Blower fan
: This should be similar to the blower
provided on the existing DC crankcase
motor as per details given in DLW drg noEL/PT/0151.
Blower Capacity
Blower output is should not less than 175
CF/Min (18.2 m/sec air velocity)
7
Specification no-MP-0.24.00.20 July 2008 Rev 01
Static Head
Vacuum should not be less then 100 mm
water gauge.
8.0 EQUIPMENT TECHNICAL REQUIREMENTS OF CYCLONIC FILTER
DUST EXHAUSTER BLOWER MOTOR WITH BUILT IN INVERTER
8.1 INVERTER- The inverter specification shall be same as that of inverter for fuel pump
motor except the following:8.1.1 Input to inverter
: Input voltage range 65V to 90 V DC
under steady state . V/f control to be
provided for constant torque operation
below 65V DC input
8.1.2 Out put frequency
8.1.3 Out put of Inverter
8.1.4 Out put power
8.1.5 Fitment
: :No exact value fixed. To be indicated in
Manufacturer data sheet.
: 3 φ AC
:0.87 HP( continuous)
: Inverter should be directly fitted on the AC
cyclonic dust extractor blower motor
8.2 AC CYCLONIC FILTER DUST EXHAUSTER BLOWER MOTOR -The motor
specification shall be same as that of motor for fuel pump except the following8.2.1 Quantity
: Two numbers
8.2.2 Rating
: 0.87HP(Continuous)
8.2.3 Frequency
: No exact value fixed. To be indicated in
Manufacturer data sheet.
8.2.4 Synchronous speed
: Not more then 3500 RPM at rated voltage
72 V DC.
8.2.5 Actual speed
: To be indicated in Manufacturer data sheet.
(at 4% slip)
8.2.6 Number of poles
: 2
8.2.7 Mech. Construction
: The mechanical construction of AC motor
shall be such that it can be readily fitted on
the existing brackets and shall be able to
adopt cyclonic dust exhauster blower fan at
one end of the motor. The motor with
inverter should not have any infringement
in its existing location on the locomotive.
The existing DC motor is as per DLW drg
no-EL/PT/0277 for Right hand motor and
drg no EL/PT/0276 for Left hand motor
8
Specification no-MP-0.24.00.20 July 2008 Rev 01
8.2.8 Blower fan
Blower Output
: This should be similar to the blower
provided on the existing DC cyclonic filter
dust exhauster blower motor as per details
given in DLW drg no-EL/PT/0276 and
0277.
: Should not less than 650 m3 /hour (10.96
m/Sec air velocity )
9
Specification no-MP-0.24.00.20 July 2008 Rev 01
9.0
TYPE, ROUTINE AND ACCEPTANCE TEST
9.1 Tests are classified as type, routine and acceptance test. These tests shall be carried out
at manufacturer’s premises and all the instrumentation facilities shall be arranged by
manufacturer.
9.2 The type test shall be carried out on one prototype unit. The routine tests shall be
carried out on all units. Acceptance test shall be carried out by the inspecting
agency for accepting the offered lot. The type test for all the requirements as laid
down in this specification shall be done by RDSO and is mandatory for product
approval or approval of manufacturer. To ensure consistency in quality Type test
shall be repeated by RDSO after every 3 year interval.
10.0 FIELD TRIAL AND PRODUCT APPROVAL
10.1 In case Inverter driven AC motor is found suitable in type test conducted by RDSO,
field trial on diesel locomotives shall be carried out on 2 sets of prototype for a
period of two months. Any modification/improvement required in the unit, felt
necessary by the RDSO following the fitment and field trials experience on the
locomotive shall be carried out by the manufacturer free of cost.
10.2 In case the field trial on locomotive is successfully completed without any problem,
the approval of prototype and further trial approval for a limited quantity shall be
given for a restricted period to be decided by RDSO. Final approval for series
application of the equipment shall be given by RDSO only after extensive use on
diesel electric locomotive.
11.0 QUALITY ASSURANCE PROGRAMME & TEST CERTIFICATE
11.1 The manufacturers shall submit their internal quality assurance programme to the
RDSO/purchaser. The manufacturer shall, on demand by the RDSO/purchaser or
any other inspecting agency nominated by the RDSO/purchaser, make the record of
checks carried out during internal quality assurance programme available for
scrutiny.
11.2Inspection shall be carried out as per the test programme given in this specification.
The manufacturer shall afford the inspector necessary assistance required to carry
out the test as given in this specification. Manufacturer shall submit two copies of
internal test results of the type test carried out as per this specification before
offering the prototype unit for type test.
11.3 Manufacturer/Tenderer shall also submit the data as asked in the Annexure
10
Specification no-MP-0.24.00.20 July 2008 Rev 01
12.0 WARRANTY
The unit shall be warranted for satisfactory and trouble free operation for a period of
2 years from the date of receipt or 18 months from the date of commissioning
whichever is earlier.
13.0 MAINTENANCE MANUAL
The manufacturer shall supply free copies of maintenance manual to
RDSO/purchasing authority and consignee.
14.0 PACKING AND MARKING
The unit shall be suitably packed in shock/waterproof boxes as to permit convenient
handling and to protect against loss or damage during transit and storage. The
equipment shall be provided with suitable rating plate for identification giving the
following:
i)
Manufacturer’s name
ii)
Type and Serial Number
iii)
Date of Manufacture
iv)
Rating
15.0 TECHNICAL PARTICULARS AND DRAWINGS
15.1 A complete set of detailed drawings of the equipment (Inverter and AC motors) shall
be submitted to RDSO for prior approval. All the technical datas, design datas,
circuit diagram and other technical parameter concerning each item of inverter and
AC small motor shall also be submitted by the manufacturers. The manufacturer
shall submit the bill of material to RDSO for prior approval. Once approved this bill
of material should not be changed by manufacturer unless approved again by RDSO.
15.2 The tenderer may suggest superior design features if any which can be considered by
RDSO/Purchaser based on overall cost benefit and technical superiority of the
design proposal, simplicity in design, construction and operational reliability etc.
16.0TEST PROGRAMME
This test programme has been prepared for type/routine/acceptance testing of
complete assembly consisting of 3 phase AC small motor with built-in inverter for
diesel locomotives.
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Specification no-MP-0.24.00.20 July 2008 Rev 01
17.0 TYPE ROUTINE AND ACCEPTANCE TEST TABLE
S.
No
Test
Nature of Test
Type
Routine
Test
Test
Test to be carried out with motor and inverter
1 Preliminary checking
Yes
Yes
2 Direction of rotation
Yes
Yes
3 Measurement of cold
Yes
Yes
resistance
4 Temperature rise test
(Measurement by
thermometer)
Yes
Yes
a) One hour heat run
No
Yes
b) Continuous heat
run
5 Temperature rise test
(Measurement by
resistance method)
Yes
Yes
18) One hour heat
No
Yes
run
b) Continuous heat
run
6 Over voltage protection
Yes
Yes
test
7 Over voltage test
Yes
Yes
8 Over load protection test
Yes
Yes
9 Short time rating test
Yes
No
10 Insulation resistance test
Yes
Yes
11 Dielectric test
Yes
Yes
12 IR test after dielectric
Yes
Yes
test
13 Reverse polarity test
Yes
Yes
14 Performance test
Yes
Yes
15 V/f control test
Yes
Yes
16 Efficiency test by Losses
Yes
No
method
17 Endurance test
Yes
No
18 Vibration & shock test
Yes
No
19 Hose proof test
Yes
No
20 Ripple current test
Yes
No
21 Harmonic level test
Yes
No
12
Clause no
Acceptance
test
Yes
Yes
No
17.1
17.2
17.3
Yes*
No
17.4.2
17.4.3
No
No
17.5
17.5
Yes
17.6
No
Yes
No
Yes
Yes
Yes
17.7
17.8
17.9
17.10
17.11
17.12
Yes
Yes
Yes
No
17.13
17.14
17.15
17.16
No
No
No
No
No
17.17
17.18
17.19
17.20
17.21
Specification no-MP-0.24.00.20 July 2008 Rev 01
Test to be carried with inverter only
22 Dry heat test
Yes
No
No
17.22
23 Damp heat test
Yes
No
No
17.23
24 Cooling test
Yes
No
No
17.24
25 Combined dust humidity
Yes
No
No
17.25
and heat test
26 Surge test
Yes
No
No
17.26
27 Short circuit test
Yes
No
No
17.27
Test to be carried out with motor only
28 Over speed test
Yes
Yes
No
17.28
29 Locked Rotor Test
Yes
No
No
17.29
30 Inter turn short test
Yes
No
No
17.30
Yes
Yes
Yes
17.31
31 Blower Performance Test
for AC Crank Case
Motor & AC Cyclonic
Filter Dust Exhauster
Blower Motor
* One out of 10 machines offered for inspection by random selection. In case the machine
does not pass the test, all the machines will be subjected to this test for acceptance.
17.1PRELIMINARY CHECKING
17.1.1The motor shall be checked for proper terminal connections and free movement of
the rotor without any noise in the bearings.
17.1.2 The radial play and axial play on the shaft shall be checked against design limits,
with a dial gauge.
17.1.3 The stator shall be checked properly for loose connection of leads, inadequate
clearance and any other visible defects.
17.1.4 Inverter shall be checked properly for the loose connections of the leads, heat sink
fins and other visible defects.
17.1.5 All fasteners shall be checked for tightness.
17.1.6 Physical dimensions of the motors with built-in inverters shall be checked in
accordance with the approved drawings.
17.2 DIRECTION OF ROTATION
The direction of rotation of the motors when started by applying a low voltage
briefly with the connections as per the terminal markings shall be the same as that
marked on the body.
17.3 MEASUREMENT OF COLD RESISTANCE
The resistance of the various windings, when cold, shall be measured by bridge or
voltage drop method in accordance with IS: 4029-1991. For the purpose of this test,
13
Specification no-MP-0.24.00.20 July 2008 Rev 01
the motor shall be left in standstill conditions for 24 hours before the measurement.
It shall be ensured that temperature of the windings of the motor is within 2 deg. C
of the mean temperature of the ambient air. The method of test, voltage, current,
resistance values and the winding temperature for each phase (UV, VW, UW) shall
be recorded.
17.4 TEMPERATURE RISE TEST (Measurement by thermometer)
17.4.1 The heat sink separately shall be heated from the side it is connected to the device
base (device base end). The temperature shall be measured at both the sides of the
heat sink (fin end and device base end) at every 5 deg rise of device base end
temperature. A graph between the temperature at fin end and device base end shall
be plotted. The temperature impedance of the heat sink shall be the slope of the
graph so plotted.
17.4.2Three phase inverter driven motor shall be arranged for normal operation at 72 V
DC input to inverter at full load. The temperature rise test shall be carried out in
the following sequences:17.4.3 One hour Heat Run Test: The motor inverter set shall be allowed to run at 72 V DC
input and at full load for one hour. Following parameters shall be recorded after
every 15 minutes during the run.
Ambient temperature before start--------Tim
Amb.
Body Temperature
Heat Sink Fins
Temp. Rise
Of motor
e
Temp.
Temp.
Body
Heat Sinks
The maximum value of temperature rise as recorded on body of motor shall not
exceed 80 deg. C with class H insulating material. The maximum heat sink fin
temperature shall be noted. The maximum temperature at the device base end shall
read from the graph plotted in clause 17.4.1. Manufacturer shall provide the device
junction temperature calculations and the value of device junction temperature
obtained by calculation shall be 25deg C less than the declared device junction
temperature of device manufacturer.
17.4.4 Continuous Heat Run Test: The motor inverter set shall be allowed to run at 72 V
DC input and at full load for continuous heat run for maximum temperature rise of
the machine. The motor shall run continuously till the motor temperature is
stabilized i.e. when last three readings are same. Following parameters shall be
recorded after every half an hourTime
Amb.
Temp.
Body Temperature of
motor
Heat Sink Fins
Temp.
Temp. Rise
Body
Heat sink
The maximum value of temperature rise as recorded on body of motor shall not
exceed 80 deg. C with class H insulating material. The maximum heat sink fin
14
Specification no-MP-0.24.00.20 July 2008 Rev 01
temperature shall be noted. The maximum temperature at the device base end shall
read from the graph plotted in clause 17.4.1. Manufacturer shall provide the device
junction temperature calculations and the value of device junction temperature
obtained by calculation shall be 25deg C less than the declared device junction
temperature of device manufacturer.
17.5
TEMPERATURE RISE TEST (Measurement by resistance method)
17.5.1 At the end of each test given in clause 17.4.3 and 17.4.4 i.e. one hour heat run and
continuous heat run, the temperature rise of each of the stator windings of motor
shall be calculated by the resistance method given below.
17.5.2 The hot resistance of the stator windings shall be measured immediately after
switching off the motors (in any case, not later than 30 seconds) and subsequent
measurement shall be carried out at intervals not exceeding 15 seconds for the first
2 minutes and 20 seconds for the next 3 minutes.
Time
Min. Sec.
Hot
resistance
between
UV
Time
Min. Sec.
Hot
resistance
between
VW
Time
Min. Sec.
Hot
resistance
between
UW
17.5.3 The maximum temperature rise of the winding shall be just after switching off the
motor. Thus the hot resistance has to be found out immediately after the motor is
switched off. But it is practically not possible to measure the hot resistance
immediately after the motor is switched off. To overcome the above difficulty the
temperature rise shall be calculated for all the readings recorded above and for all
the three phases (UV, VW, UW) a graph between time and temperature rise
calculated shall be plotted. The temperature rise at the zero time shall be found by
extrapolating the curve so plotted to zero time point. The temperature rise so
obtained at zero time for each winding shall not exceed 80 deg C.
17.5.4 Method of calculation of Temperature Rise by Hot Resistance Method
Formula:
Hot Resistance per Phase X (235 + Tamb) = 235 + Tamb + Trise
Cold Resistance per Phase
Tamb =
Ambient temperature
Trise = Temperature rise
15
Specification no-MP-0.24.00.20 July 2008 Rev 01
17.5.5 The continuous heat run test shall be done again on the motor (without inverter) fed
by industrial AC supply and temperature rise of the each of the stator winding of
motor shall be calculated by the resistance method. The difference in temperature
rise of winding with and without inverter shall not be more than 2 deg C.
17.6
OVER VOLTAGE PROTECTION TEST
The motor inverter set shall trip at 100 V DC input voltage. The unit shall work
satisfactorily after completion of this test.
17.7
OVER VOLTAGE TEST
The inverter driven motor working at full load, shall be subjected to an input DC
voltage of 100 volts for a period of five minutes. This test shall be done after
bypassing the over voltage protection of inverter. The unit shall work satisfactorily
after completion of this test.
17.8
OVER LOAD PROTECTION TEST
The motor inverter set shall trip at 1.5 times the rated current. It shall work
satisfactorily after completion of this test.
17.9
SHORT TIME RATING TEST
The motor inverter set shall satisfactorily withstand for 10 sec at rated voltage, a
current equal to minimum of 1.5 times the rated current or the short time current
value as declared by manufacturer. This test shall be done after bypassing the
overload protection of inverter. The motor inverter set shall work satisfactorily
after completion of this test.
17.10 INSULATION RESISTANCE (IR) TEST BEFORE DIELECTRIC TEST
Insulation resistance value of the motor with inverter shall be measured and
recorded. It should not be less than 10 mega ohms.
17.11 DIELECTRIC TEST
This test shall be carried out on motor and inverter separately. The test voltage
shall be alternating sine wave, frequency being 50 Hz to 60 Hz. For motor a test
voltage of RMS value of 1.2 KV shall be applied for a period of one minute
between AC winding of each phase and the frame. For inverter a test voltage of
RMS value of 1.2 KV shall be applied for a period of one minute between shorted
connections and frame. The motor/inverter shall be connected at a voltage of less
than one third of test voltage and shall be increased gradually to the full test
16
Specification no-MP-0.24.00.20 July 2008 Rev 01
voltage. The test shall be considered satisfactory if neither a disruptive discharge
nor a flash over occurs.
17.12 IR TEST AFTER DIELECTRIC TEST
Insulation resistance of the motor with inverter shall be measured after the
dielectric test and there shall be no appreciable difference between the two values,
one before the test and one after the test.
17.13 REVERSE POLARITY TEST
The motor inverter set shall be connected to 72 volts DC input supply in reverse
polarity for a period of 2 minutes. This shall be followed by 100 ON and OFF
cycles (each cycle consisting of 90 sec ON and 30 sec OFF). At the end of the test,
the motor inverter set shall work satisfactorily when the connections at the input
are restored to correct polarity.
17.14 PERFORMANCE TEST
The motor inverter set shall be mechanically loaded according to its rating. The
performance characteristics shall be observed at 65 V, 72V and 90 V DC input to
inverter. The following parameters shall be recorded:a) Input DC voltage to inverter (Vdc).
b) Input DC current to inverter (Idc).
c) Output AC volts of inverter (Vac).
d) Output AC current of inverter (Iac).
e) RPM
f)
Input frequency in Hz.
g) Torque in Kgm.
h) Powerfactor
i)
HP(of motor) to be calculated by formula HP= 2π x RPM x Torque(in Kgm)
4500
i)
Efficiency of complete set to be calculated by formula η= 746x HP x100 %
Vdc x Idc
j)
Calculate Inverter efficiency=
√3Vac X Iac X Powerfactor
Vdc X Idc
The output AC volts of inverter, input frequency, powerfactor recorded at 65 V,
72V and 90 V DC input to inverter shall be within the design limits. The HP (of
motor), efficiency of complete set, inverter efficiency calculated at 65 V, 72V and
90 V DC input to inverter shall not be less than the design values.
17
Specification no-MP-0.24.00.20 July 2008 Rev 01
17.15 V/f CONTROL TEST
The inverter motor set shall be mechanically loaded according to its rating. The
voltage shall be varied from 20V to 65V (17 V to 65 V for AC Fuel Pump Motor)
in steps of 10 Volts. The following parameters shall be recorded:1. Output AC volts of inverter ( Vac).
2. RPM
3. Input frequency in Hz.
4. Torque in Kgm.
The ratio Vac/f shall be calculated. The values so obtained shall be within +20% of
nominal value. The torque measured shall not be less than 70 % of full load torque.
17.16 EFICIENCY TEST BY LOSSES METHOD
The motor inverter set shall be mechanically loaded according to its rating at 72V
DC. The following parameters shall be recorded:a.
b.
c.
d.
e.
f.
Input DC voltage to inverter (Vdc).
Input DC current to inverter (Idc).
Input AC volts to motor (Vac).
Input AC current to motor (Iac).
RPM (N)
Powerfactor
The motor inverter set then shall be run without load at 72V DC. The following
parameters shall be recorded:a.
b.
c.
No load Input DC volts to inverter ( Vnl dc).
No load Input DC current to inverter (Inl dc).
No load Input AC current to motor (Inl ac)
Following calculations shall be doneInverter η
Input power to inverter
Input power to motor
Friction & winding loss
(F&W loss)
No load input power
No load losses
Rc
= √3Vac X Iac X powerfactor
Vdc X Idc
=Vdc X Idc
= out put power of inverter
= Input power to inverter X Inverter η
= 5 % of rated HP
= Vnl dc X Inl dc
= No load Input power x Inverter η
= Average Hot resistance per phase (as calculated in
18
Specification no-MP-0.24.00.20 July 2008 Rev 01
clause 17.5.3 )
Total No load I²R loss
= 3/2( Inl ac)² xRc
Fixed losses
= No load losses-Total No load I²R loss- F&W loss
Total I²R stator loss
= 3/2 (Iac) ²xRc
Total stator loss
= Total I²R stator loss +Fixed losses
Rotor Input
=Input power to motor –Total stator loss
Slip
=( Ns-N)/Ns
Rotor loss
= Rotor input X Slip
Output power
=(Rotor input-Rotor loss-Friction & winding loss)
Efficiency of complete set
= output power/Input power to inverter
The efficiency of complete set calculated shall not be less than design value.
17.17 ENDURANCE TEST
The motor with inverter at 72 V with its driven load shall be kept in a heat
chamber for subjecting it to endurance test at 55 degree centigrade for a period of
100 hours. After completion of this test, it should be checked for any adverse sign.
17.18 VIBRATION, SHOCK& BUMP TEST
17.18.1The motor with inverter shall be subjected to this test in three orthogonal planes,
under ambient temperature condition of the testing area, the maximum acceleration
of shocks shall be equal to 3g in each of three directions, longitudinal, transverse
and vertical. For this test, the equipment is secured in a suitable position to a
machine producing vibrations of sinusoidal form with adjustable amplitude and
frequency. The method of carrying out this tests is as per clause 17.18.2
17.18.2 Determination of resonant frequencies:
In order to determine the possible existence of critical frequencies producing
resonance, the frequency shall be varied progressively from 1Hz to 100 HZ within
a time of not less than 4 min. The amplitude of the oscillations ‘a’ expressed in
mm shall be given as a function of ‘f’ by the equations
a = 25/f for values of ‘f’ between 1 Hz to10 Hz.
a = 250/f² for values of ‘f’ between 10 Hz to100 Hz.
19
Specification no-MP-0.24.00.20 July 2008 Rev 01
If resonance is produced, the corresponding frequency shall be maintained for 4
minutes in each case.
17.18.3 Test with Sustained Vibrations:
The equipment with power applied shall be subjected with sustained vibrations for
a period of a minimum 8 hours in all the three directions at the frequency• Either at the critical frequencies, if any such well-defined frequency has been
detected
• Otherwise at a frequency of 10 Hz
In both the cases, the amplitude of the vibrating table shall be adjusted to the value
corresponding to the frequency concerned.
17.18.4 Test to simulate the effect of shunting shocks:
The equipment with power applied shall be subjected to a series of three
successive shocks at 50 Hz vibrations each corresponding to a maximum
acceleration of 3g in all the three direction.
17.18.5 Results of tests :
The tests are considered to be satisfactory if there is no resulting damage or
abnormality in operation. The equipment shall be able to withstand successfully
the performance test and dielectric test as per clause 17.14 and 17.11.
17.19 HOSE PROOF TEST
The inverter shall be tested as per IS 4691 and shall conform to IP65. Motor shall
be tested as per IS 4691 and shall conform to IP54. Inverter and motor shall work
satisfactorily after completion of this test.
17.20 RIPPLE CURRENT TEST
The inverter motor set shall be loaded according to its rating at 72V. The ripple
current at input DC shall be measured. The ripple current recorded shall not be
more than 5%.
17.21 HARMONIC DISTORTION LEVEL TEST
The inverter motor set shall be loaded according to its rating at 72V. Harmonics
generated at the inverter output shall be measured and harmonic distortion level in
% shall be less than 5% upto 20th harmonic (upto 1000 hz) on current.
20
Specification no-MP-0.24.00.20 July 2008 Rev 01
17.22 DRY HEAT TEST (Clause 5.6 of IEC-571-1)
The inverter with power applied shall be placed in a test chamber where the
temperature is progressively raised from the ambient to 70+2 deg centigrade over a
period of half an hour. The unit shall be kept in this condition for 6 hours. At the
end of this period, performance test shall be carried out and the requirements
specified in the clause 17.14 should be met.
17.23 DAMP HEAT TEST (Clause 5.7 of IEC-571-1)
The inverter without power applied shall be placed in a test chamber where the
temperature is progressively raised from the ambient to 55+2 deg centigrade over a
period of 1.5 to 2.5 hours, the relative humidity being between 95% and 100%.
The unit shall be kept in this condition for 10 hours. At the end of this period, the
temperature is lowered to the ambient temperature over a period of 3 hours,
relative humidity being between 95% and 100%. After the end of this period, the
performance test and dielectric test shall be carried out and the requirements
specified in the clause 17.14 and 17.11 should be met.
17.24 COOLING TEST (Clause 5.5 of IEC-571-1)
The inverter shall be placed in a chamber where the temperature is progressively
lowered from the ambient to –10 deg. C over a period of at least half hour. The
inverter shall be kept in this condition for 2 hours. After this test, the performance
test shall be carried out and the requirements specified in the clause 17.14 should
be met.
17.25 COMBINED DUST HUMIDITY AND HEAT TEST (Clause 5.9 of IEC-571-1)
The inverter with power applied shall be placed in a test chamber where the
temperature is progressively raised from the ambient temperature to 70+2 deg.
centigrade in a period of time between 1.5 hr. and 2.5 hr. with a relative humidity
of 95% to 100%. Quantity of dust mutually agreed shall then be sprayed over the
equipment. At the end of this test, the performance test and dielectric test shall be
carried out and the requirements specified in the clause 17.14 and 17.11 should be
met.
17.26 SURGE TEST (Clause 5.4 of IEC-571-1)
Inverter shall be subjected to transient non repetitive surge between the supply
points at 1.8 KV for 45µsec duration (using capacitor discharge circuit). The surge
voltage shall be applied in both positive and negative direction. The test shall be
21
Specification no-MP-0.24.00.20 July 2008 Rev 01
considered satisfactory if the equipment continues to operate without malfunction
or damage both during and following application of the voltage surge. After this,
the performance test shall be carried out and the requirements specified in the
clause 17.14 should be met.
17.27 SHORT CIRCUIT TEST
The inverter shall be loaded according to its rating. A short circuiting contactor
shall be connected in parallel with the load. The short circuiting contactor shall be
closed after the normal current through the load has been recorded for one minute.
The resulting fault current shall be detected and cleared by the protective circuit of
inverter. Inverter shall work satisfactorily after completion of this test.
17.28
OVER SPEED TEST
The motor shall be run at a speed of 1.25 times the rated speed for a period of 2
minutes. The motor shall work satisfactorily after completion of this test.
17.29 LOCKED ROTOR TEST
Locked rotor test shall be conducted at 38V, 40V, 42V AC input supply to motor.
This test shall be done with four position of rotor 90 degree apart. Input Current
drawn by motor and Torque available shall be recorded. The value of Input Current
drawn by motor shall not be more than the declared value of starting current given
by manufacturer. The value of starting torque obtained shall not be less than the
declared value of starting torque given by manufacturer.
17.30 INTER TURN SHORT TEST
The motor stator winding shall be tested for inter turn short (without its rotor in
position) at test voltage of 2 KV (peak to peak). There should not be any interturn
short on the stator.
17.31 BLOWER PERFORMANCE TEST
Air velocity at the outlet will be measured, it should not be less then under
mentioned data:
Motor
AC Crank Case Motor
Static Head
100 mm
Blower Output
Should not less than 175 CF/M
(18.2 m/sec air velocity)
AC Cyclonic Filter Dust
Exhauster Blower Motor
Should not less than 650 cubic
met/hour (10.96 m/sec air velocity
22
Specification no-MP-0.24.00.20 July 2008 Rev 01
Annexure
Data to be furnished by Manufacturer/Tenderer
INVERTER
1
2
3
4
5
6
7
8
Continuous rating (voltage , current, output power)
Short time rating for 10 sec duration
Protections provided
Ripple current at input
Output wave shape and % harmonics at full load
Switching device
-type
-make
-rated voltage & current
- characteristics curve
-maximum permissible junction temp for the device as given by device
manufacturer
-Maximum heat sink temperature
Type of protection of cabinet
DC output of DC chopper (if applicable)
MOTOR
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Application
Type of induction motor
Rated voltage, current
Type of connection -Star/Delta
Frequency
Speed
Continuous rating HP
Short time rating
Slip at full load in percentage at rated voltage
Class of insulation of winding
Type of enclosure
Method of ventilation
Type of protection
Frame size
Overall dimension of complete motor inverter set
Type and make of bearing
Size of bearing and their estimated L10 life
23
Specification no-MP-0.24.00.20 July 2008 Rev 01
18
19
Rotor construction
Starting current and torque in kgm
-at 38V AC
-at 40VAC
-at 42 VAC
20 Type of Enameled wire used as per IS 13730 Pt 13
21 Brand name of insulating material proposed to be used
22 Overall efficiency of motor inverter set
23. Weight of inverter motor set
24
Modification sheet No.: MP.MOD.EM.01.07.08 (Rev. – 00)
Government of India
Ministry of Railways
Research Designs and Standards Organization
Manak Nagar, Lucknow – 226011.
Modification sheet No.: MP.MOD.EM.01.07.08 (Rev. – 00), Dated: 30.09.08
Title
Implementation of auto reset feature & increase in starting torque in AC Fuel
Pump Motor developed by M/s Signotron (India) Pvt Ltd. Kolkata.
Objectives
Sheds have been reporting the following two types of problems on the AC fuel
pump motors of M/s Signotron India on ALCO locomotives;
a) Cases of stalling of the AC fuel pump motors during locomotive cranking.
This problem is more on locomotives fitted with GE/EDC governor as in this
case, the fuel motor has to drive two pumps together ie, the fuel pump itself as
well as the governor pump.
b) Intermittent shutting down of the motor during locomotive operation, while no
abnormality is noticed in shed during investigations.
The object of this MOD sheet is to address issues related to stalling during
cranking and intermittent shut down of the motors during loco operations.
Background
During cranking, if battery voltage dips below 20 V, the V/f ratio drops below the
minimum required value of 2/3 leading to reduction in torque produced by the AC
fuel pump motor (less than 70% of the full load torque value). This reduction in
torque leads to stalling of the motor. The stalling is more on locomotives fitted
with GE/EDC governors.
The Intermittent shutting down of the AC fuel pump motor occurs due to any
short circuit in the motor-inverter circuit. In all such cases, the unit goes into
latched trip condition ie unless the inverter circuit is reset (to release the latch),
the unit cannot be restarted. To enable restart, the Fuel Pump MCB is to be put
“OFF” and then “ON”.
In view of the above, RDSO advised the firm to implement ‘Auto restart
feature’ so that the unit restarts within 5 seconds automatically without resetting
the MCB in case of short circuit trip.
1
Modification sheet No.: MP.MOD.EM.01.07.08 (Rev. – 00)
RDSO also advised to firm to modify the inverter card so as to keep the V/F
ratio constant to upto 17 volts at the time of cranking. This would ensure torque
of more than 70% (of full load torque) even if the battery voltage drops to 17 V
during cranking.
Modification Content
To implement auto reset feature M/s Signotron has introduced a Micro controller
in inverter card. This modified card generates a reset signal to restart the motor
within 5 seconds whenever any short circuit trip occurs. This reset signal is
generated up to three times, thereafter the micro controller will latch the system &
the unit power will have to be reset through the circuit breaker to restart the unit.
To achieve constant V/F ratio to up to 17 volts at the time of cranking &
there by to maintain the torque at more than 70%, the embedded software of the
micro controller will have to be modified.
APPLICATION
On all existing AC fuel Pump motor fitted on ALCO design diesel electric
locomotives.
Agency for implementation
M/s Signotron has implemented these modifications on new AC fuel motors with
effect from 30/06/08 (cut in Sl. No. 08061733 onwards). Railways are advised to
send their AC Fuel Pump motors to M/s Signotron for modifications.
Distribution as per enclosed list.
Encl: Nil
(Vivek Khare)
for Director General/M.P
2
Modification sheet No.: MP.MOD.EM. 02.08.08 (Rev. – 00)
Government of India
Ministry of Railways
Research Designs and Standards Organization
Manak Nagar, Lucknow – 226011.
Modification sheet No.: MP.MOD.EM. 02. 08.08, (Rev. – 00), Dated: 30.11.08
1.0 Title: To increase the suction capacity of AC Crank Case Motor developed by M/s
Signotron (India) Pvt. Ltd., Kolkata.
2.0Background: Railways have reported problem of low vacuum creation in the diesel
locomotive Crankcase by the AC Crank Case Motor developed by M/s Signotron
India Pvt. Ltd. Kolkata
.
The rpm of AC Crank Case motor was kept at 3000 (at 50 Hz) by the firm, due to the
inherent slip in AC motors the effective rpm got reduced to 2880. The vacuum
created on a test bench with this blower/motor was found to be in the range of 80-85
mm, against this, the vacuum obtained by DC Crank Case motor on the test bench is
more than 90 mm.
3.0 Object: The objective of this MOD sheet is to furnish guidelines for
rectification of the crank case motor assembly supplied by M/s Signotron ltd,
so that higher vacuum creation may be achieved in the crankcase of Diesel
locomotives.
4.0Method of Vacuum measurement in shed:
The test stand for vacuum
measurement can be set up in the shed/ workshop. The CC motor assembly should
be mounted on a table. A capillary tube should be connected between suction end of
blower and manometer through an orifice as shown in figure below. Battery supply
voltage of 65-72 volts is to be given to inverter. The Suction head (vacuum) is
measured through difference in water level in manometer tubes.
Method of Vacuum Measurement
1
Modification sheet No.: MP.MOD.EM. 02.08.08 (Rev. – 00)
5.0
Modification Content:
As per advise of RDSO, the
firm has modified the
inverter card to obtain the
current output at 57 Hz
(from 50 Hz) and thus
increase the motor rpm to
3420 (from 3000). To
achieve this, a new software
was loaded in the IC of the
inverter card.
modified software to be
loaded in this micro chip
This modified AC motor was
tested by RDSO on a test
bench and 100 mm vacuum
was obtained.
6.0 Application: The Firm has modified the card and implemented the same in newly
manufactured motors from Aug, 2008 from Sno-08081631 on wards.
This modification is to be implemented in all existing AC Crank Case motors fitted on
diesel locomotives.
7.0 Agency for implementation: Railways are advised to send their AC Crank Case
motors to M/s Signotron for modifications.
8.0 Distribution as per enclosed list.
Encl: Nil
(Vivek Khare)
for Director General/M.P
2
Modification Sheet No.MP.MOD.EM-11-64-10, (Rev 00)
Government of India,
Ministry of Railways
Research Designs & Standard Organization
Manak Nagar, Lucknow – 226011.
Modification Sheet No. MP.MOD.EM- 11.64.10, (Rev. 00), Dated 31.05.2010
1.0
TITLE:
Use of hybrid bearings 6304-2RSL3/ HC5C3S0WT and radial shaft seal CR
20X45X7 HMS5V in AC Crank Case Exhauster motor to improve reliability and
performance.
2.0
BACKGROUND:
Railways have reported the failures of drive end bearing 6305-2RS1/C3, non
drive end bearing 6204-2RSH/C3 and seal used in AC Crank Case motor. At
present M/s SKF make imported (European origin) rubber sealed bearing is
recommended for use in these motors.
3.0
OBJECT:
The object of this MOD Sheet is to introduce hybrid bearings 63042RSL3/HC5C3S0WT in both ends of AC Crank Case Exhauster motor and Viton
material radial shaft seal to improve reliability and performance.
4.0
4.1
INVESTIGATION:
Due to repetitive failure of these bearings and rubber oil seals, a failure analysis
was carried out by RDSO with M/s SKF. Main reasons of these failures are
observed as under:
•
•
•
•
High temperature (From Exhaust gas of Crank Case).
Lubrication failure (High oil bleed rate from grease).
Failure due to Electric current passage through bearing.
Failure of oil ingress due to rubber oil seal.
4.2
The use of frequency modulator (in the IGBT inverter) and exposure to high
temperature in the application is a potent reason for failures.
5.0
APPLICATION TO CLASS OF LOCOMOTIVES:
All BG Diesel electric ( ALCo ) locomotives.
6.0
MODIFICATION CONTENT:
6.1
The analysis of failure has shown that bearing with non metallic balls (hybrid
bearings) and radial shaft seal made of Viton material would be more suitable for
this application.
Page 1 of 3
Modification Sheet No.MP.MOD.EM-11-64-10, (Rev 00)
6.2
The hybrid bearing and Viton seal description are as under:
Bearing Description:
Bearing
Radial Clearance
Seals
Ball Material
Grease
SKF make 6304-2RSL3/ HC5C3S0WT
C3
RSL- Low friction seal of ACM material
Silicon Nitride
WT
Radial Shaft Seal Description (for application with hybrid bearing):
Seal
Seal Material
Permissible operating Temp.
Pressure differential[MPa/psi]
Rotational speed[r/min]
SKF CR 20X45X7 HMS5V
Viton material
min -40°C max 200°C
0.03/4.35
10695 at Circumferential speed 14m/s
6.3
The firms have been advised to cut in hybrid bearings in a phased manner
against future supply.
6.4
Retro fitment of this bearing in all existing motors would require a change in
armature and the end covers as the bearing diameter is different. Retro fitment is
therefore not desirable at this stage.
6.5
Application of Viton seal can be implemented immediately in the existing motors.
The size of the seal for these motors shall however be different and the
description is SKF CR 25X45X7 HMS5V.
7.0
Materials required and sources of supply:
7.1
For new supply, the hybrid bearing and viton seal will be fitted in motors by motor
manufacturer.
7.2
Viton seal for existing Crank case motors (to Part no. CR 25X45X7 HMS5V)
will be supplied by M/s SKF authorised distributors.
8.0
ADDITIONAL INFORMATION:
8.1
Advantages of Ceramic Hybrid Bearing
(a)
Protection against Stray current leakage: The development of frequency
converters in motor applications has increased the threat for stray electrical
currents in electrical drives; the bearing damages are observed when motors are
supplied from a pulse width modulation converter. The use of ceramic (insulator)
for making balls in place of steel ball to make the bearing suitable for use even in
the presence of such stray currents.
Page 2 of 3
Modification Sheet No.MP.MOD.EM-11-64-10, (Rev 00)
(b)
Tolerant to poor lubricating condition: Hybrid bearings outperform all-steel
bearings in terms of wear-resistance when it comes to poor lubrication and
contaminated environments. Silicon nitride has superior behavior to metal
contact under pure sliding conditions, because of the smoother surface and the
higher hardness of the ceramic rolling elements.
(c)
Reduced Heat Generation: Low frictional characteristics of the silicon nitride
ball results in lower heat generation and lower operating temperatures.
(d)
Thermal Stability: With thermal expansion being 1/3 that of steel, the silicon
nitride ball reduces the effects of thermal gradients across the bearing thus
reducing the risk of bearing seizure.
(e)
Corrosion Resistance: Excellent resistance to corrosive media allows for
extended bearing life. Silicon nitride balls with their resistance to corrosion and
high hardness levels allow for continued use and self healing of the deteriorated
raceway surfaces.
8.2
Advantages of Viton Seal
(a)
The viton seal can sustain temperature up to 200º C. Shaft at drive end side of
C.C. motor experiences temperature approx 150º C.
(b)
No leakage at high temperature.
(c)
Lip design optimize for low friction.
9.0
AGENCY AND SCHEDULE OF IMPLEMENTATION:
9.1
In new AC Crank case motors, the hybrid bearings and Viton seal shall be
supplied by the manufacturer of motor.
9.2
In existing C.C. motor the modification shall have to be carried out by Diesel
sheds/POH shop.
10.0
DISTRIBUTION: As per enclosed list.
11.0
REFERENCE: Nil
(Vivek Khare)
for Director General/MP
Page 3 of 3
Modification Sheet No.MP.MOD.EM-02.04.11, (Rev. 00)
Government of India,
Ministry of Railways
Research Designs & Standard Organization
Manak Nagar, Lucknow – 226011.
Modification Sheet No. MP.MOD.EM- 02.04.11, (Rev. 00), Dated.21.04.2011
1.0 TITLE:
Improvement measures for 3 phase AC small motors.
2.0 BACKGROUND:
2.1
Railways have been reporting high rate of failures of AC auxiliary motors.
RDSO has taken several steps in this regard and issued various modification sheets
/Instruction Bulletins as under:
Sl.
1.
2.
Mod. sheet No & IB
MP.MOD.EM.01.07.08
(Rev. – 00),
Dated 30.09.08
MP.MOD.EM. 02. 08.08, (Rev.
– 00), Dated 30.11.08
Title
Implementation of auto reset feature & increase in
starting torque in AC Fuel Pump Motor developed by
M/s Signotron (India) Pvt Ltd. Kolkata.
To increase the suction capacity of AC Crank Case
Motor developed by M/s Signotron (India) Pvt. Ltd.,
Kolkata.
Use of hybrid bearings 6304-2RSL3/ HC5C3S0WT
and radial shaft seal CR 20X45X7 HMS5V in AC
Crank Case Exhauster motor to improve reliability and
performance.
Modification in terminal box cover of AC small motors.
3.
MP.MOD.EM- 11.64.10,
(Rev. 00), Dated 31.05.2010
4.
MP.MOD.EM- 15.71.10,
(Rev. 00), dt.29.06.10
Instruction Bulletin no. MP.IB.
To lay down broad guidelines for testing of AC Fuel
EM.13.44.08 Dated 10.12.2008 Pump Motor, AC Crank Case motor and AC Cyclonic
Filter motors fitted on ALCO locomotives.
5.
6.
MP.MOD.EM- 01.01.11,
(Rev. 00), dt.17.02.2011
7.
Vide letter no. SD. Aux. F.P.
Motor Dated 17.04.08
8.
Stand by inverter for AC Fuel Pump motor.
In connection with Use of M/s SKF make “2RS”
imported (European origin) bearings in small DC motor
and small AC motors.
Development of 2 HP AC FP motor which is running on trial from Mar 2010 onwards at
DLS HWH without any abnormality.
2.2
Maximum number of failures is still on the inverter portion of the unit. A detailed
analysis of the failures was carried out and an action plan formulated to mitigate the
existing problems in a meeting with technical experts of M/s Signotron and DLW on
24.02.2011. RDSO & DLW have jointly carried out quality audit of the firm.
Modification Sheet No.MP.MOD.EM-02.04.11, (Rev. 00)
Corrective action has been initiated with the supplier. Some modifications are required to be
implemented in diesel sheds by the firm, the same have been elaborated in the para 5.0.
3.0 OBJECT:
The objective of this modification advice is to appraise the sheds regarding the
modifications to be carried out by the firm to improve the reliability of AC small motors.
4.0 APPLICATION TO CLASS OF LOCOMOTIVES:
All BG Diesel electric ALCo locomotives equipped with AC auxiliary motors.
5.0 MODIFICATION CONTENT:
SI.
No.
1.
Modification Content
Epoxy coating on PCB:
Presently the firm is
applying
Transparent
conformal coating material
to the electronic circuitry to
act as protection against
moisture, dust, chemicals
and temperature extremes.
RDSO has now advised the
firm to implement epoxy
coating on PCBs to arrest
loose connections due to
vibration, etc.
Action plan for warranty motors
Doctor Beck ELANTAS Epoxy coating shall be
done to prevent components against moisture,
dust. It will give mechanical strength against
vibration.
Epoxy coated PCB’s component side view
Epoxy coated PCB’s soldering side view
Initially the firm shall provide 5 Nos. of epoxy
coated PCB to each of the shed, in exchange, 5
Nos. of non epoxy coated PCBs shall be taken
back from the shed and shall be recycled back
to the shed with epoxy coating. This shall
continue till all motors under warranty are
covered.
Applicable to
Fuel Pump motor
Crank Case motor
Dust Blower motor
Modification Sheet No.MP.MOD.EM-02.04.11, (Rev. 00)
SI.
No.
Modification Content
Action plan for warranty motors
Applicable to
Based upon experience gained with epoxy
coating the shed shall subsequently implement
this on the balance PCB’s also.
2.
3.
Provision
of
PCB
connector for IGBT &
Zener diode connection:
Previously the firm used to
solder the zener diode on
the IGBT directly. Recently
some cases of loose
connections
were
observed. It has therefore
been decided to use a
small PCB to connect
between zener diode and
IGBT to prevent loose
connections.
Use of cold forge bolts:
The firm has been advised
to use only cold forged
bolts for mounting of the
inverter and these should
be sourced only from M/s
TVS or Unbrako or GKW.
4.
Thread sealant to prevent
nut/screw loosening due
to vibration
5.
Up-gradation
of
D.B
motor’s inverter as a
stand by inverter for F. P
This shall be provided to all Diesel Sheds in lots
of 3-4 to cover all motors under warranty.
PCB connector
Based upon the experience gained with the
small PCB between zener diode and IGBT shed
shall subsequently implement this on the
balance PCB’s also.
This shall be provided to all Diesel Sheds in lots
to cover all motors under warranty.
For motors, out of warranty, shed shall procure
cold forged bolts and replace all the existing
bolts.
• Thread locker Loctite 290 or equivalent shall
be used on all the fasteners inside the
inverter.
• Thread locker Anabond 112 or equivalent
shall be used on the inverter mounting bolts
(4 nos.).
• The firm shall provide adequate thread locker
for under warranty motors.
• Sheds shall procure additional sealant to
cover all out of warranty inverters.
This modification shall be incorporated as per
RDSO modification sheet no. MP.MOD.EM01.01.11 (Rev00). Firm shall carry out
--do--
--do--
--do--
Dust Blower motor
Modification Sheet No.MP.MOD.EM-02.04.11, (Rev. 00)
SI.
No.
6.
Modification Content
motor:
Firm has been advised to
upgrade D.B motor inverter
to
use it as a stand by inverter
for Fuel Pump motor to
clear section during line
failures.
Implementation
of
modified software for
Fuel Pump motor.
Action plan for warranty motors
Applicable to
modification on one locomotive at each shed
after that the sheds themselves shall modify
other locos accordingly.
To implement on 10 locos each at N.Rly &
ECoR for field trial.
Fuel Pump motor
6.0 Materials required and sources of supply:
As mentioned above.
7.0 ADDITIONAL INFORMATION:
Firm shall also incorporate all above modifications in pending purchase orders. Firm has been
advised to incorporate the under mentioned modifications in the new supply:
• Inclusion of burn in test as per RDSO specification No. ELRS/SPEC/SI/0015 for 8 hours as
a routine test for all the PCBs.
• Introduce improved design oil seal for C.C motor to prevent ingress of oils/fumes.
• Use of Hybrid bearings in C.C motor.
• Increase starting torque by 30% of AC Fuel Pump motor to overcome stalling problems.
• 100% computerised testing of all component soldering to prevent dry solder failures.
• Lead free soldering material is recommended.
8.0 AGENCY AND SCHEDULE OF IMPLEMENTATION:
8.1
These modifications shall be done through the supplier of the equipment.
8.2
All Diesel sheds and POH shops shall carry out this modification as and when
possible.
9.0 DISTRIBUTION: As per enclosed list.
10.0 REFERENCE: Nil
(Vivek Khare)
for Director General/MP