Download WIRE WOUND RESISTORS

WIRE WOUND RESISTORS
Power ratings range from 20 to 500 watts for a single tube. Resistance values are
offered from less than 1 ohm to about 100 kilo ohms.
Resistors used in the following applications:





Resistive load banks (dummy load) for testing apparatus and battery
discharging.
Mains suppressor circuits.
Voltage dropping circuits.
Current limiting circuits.
Dynamic braking of DC motor variable speed drives (VSD).
Three types of metal alloys are preferred for our resistor windings namely; Coppernickel (CuNi); nickel-chrome (NiCr); chrome-aluminium (CrAl).
General resistor specifications:
 Temperature factor of resistance for CuNi:
1%@250°C
 Temperature factor of resistance for NiCr:
1%@250°C
 Temperature factor of resistance for CrAl:
3%@250°C
 CrAl is resistant to sulphurous atmospheric environments.
 NiCr is non-magnetic so does not attract magnetic dust particles.
 NiCr is also more corrosion resistant at room temperature.
 Maximum design temperature
<350°C
 Dynamic braking resistors momentary temperature:
<450°C
 Application voltage:
1kV
 Maximum design voltage;
3kV
 Terminals and mounting feet:
304 stainless
steel.
 Resistor core material:
Cordierite
based.
 Resistor insulator material:
Siliceous porcelain.
SINGLE TUBE RESISTORS RANGE BETWEEN 20-500 WATTS.
Often power ratings of more than 500 watts are required but then we use several 500
watt “open winding” wire wound resistors connected in either series or parallel and
can offer an enclosure with connection terminals.
Si-Cer RESISTOR COATING
Our world-class green resistor coating is a silicon-based, heat resistant formula using
state-of-the-art VOC compliant water dispersible silicon resin. It is used where resistors
are subjected to harsh environmental conditions:






Temperature of 600°C
Salt spray
Moisture
Chemical corrosion
Thermal cycling
UV light
RESISTOR DIMENSIONS FOR SMOOTH AND MEALIE COB TYPE RESISTORS
SMOOTH TUBE RESISTORS
Smooth tube type
Power rating:
A- TUBE LENGTH (mm)
B- TOTAL HEIGHT
C- TERMINAL WIDTH
D- TUBE Ø OD
d- TUBE Ø ID
E- MOUNTING HOLES
CENTRE-TO-CENTRE
F- CONNECTION BOLT Ø
H- TOTAL LENGTH
20W 25W 30W 40W 50W 75W
55
60
6.8
16
9
3
85
63
60
6.8
16
9
3
93
80
60
6.8
16
9
3
120
120
60
6.8
16
9
3
150
100W
150W
200W
250W
250W
300W
400W 450W
100
80
8
31
19
134
80
8
31
19
150
80
8
31
19
200
80
8
31
19
247
80
8
31
19
320
80
8
31
19
200
100
10
45
20
250
100
10
45
20
300
100
10
45
20
350
100
10
45
20
145
179
195
245
292
365
245
295
345
395
4
165
4
199
4
215
4
255
4
302
4
375
6
265
6
315
6
365
6
415
MEALIE COB RESISTORS
Mealie cob type
Power rating:
A- TUBE LENGTH
B- TOTAL HEIGHT
C- TERMINAL WIDTH
D- TUBE Ø OD
d- TUBE Ø ID
F- CONNECTION BOLT Ø
100W 200W 300W 400W 600W
100
85
21
45
10
6
155
85
21
45
10
6
205
85
21
45
10
6
255
110
21
45
10
6
305
110
21
45
10
6
ENCLOSED RESISTORS
Resistors for load testing purposes can be supplied in enclosures if requested. Read
more on our LOAD BANKS page.
LOCOMOTIVE RESISTORS
Transnet Engineering regularly requires replacement variable wire wound resistors for
class 10M5 locomotives. These resistors are referred to as a motor coach headlight
and voltage regulator resistor and described as the following:




U1639
U1634
7E47
7E44
31x247mm variable.
31x134mm variable.
31x247mm fixed.
31x134mm fixed.
Capacitor discharge resistors:
After power is removed the charge on the capacitor will drain off through this
"bleeder resistor", causing the voltage to decay quickly to safe levels. While the
power supply is on, a small current flows through the bleeder resistor, wasting a small
amount of power.
RESISTOR REPLACEMENTS FOR ELECTRIC LOCOMOTIVES
We are also able to manufacture replacements for obsolete resistors such as these
electric locomotive resistor panels:
Resistor panel for indicating lamps:
Old panel:
New Panel:
Resistor panel for braking control:
Old panel:
Excitation resistor panels
New panel:
Resistor panel for sealed beam headlight lamps:
Old panel:
New panel:
PLATE RESISTORS
We also offer single flat plate wire wound resistors capable of dissipating 3,000 watts
(3kW). As with all of our resistors, several may be connected in a series/parallel
manner to obtain higher power ratings. Their flat shape promotes better cooling.
SIZE: 540x100mm
POWER: 1,000 WATTS (1kW)
SIZE: 700x150mm
POWER: 3,000 WATTS (3kW)