Download Automatic voltage regulator AVR6-V2, AVR6-V3

AUTOMATIC VOLTAGE REGULATOR AVR6-V2, AVR6-V3
I. The automatic voltage regulator AVR6 is intended to equip the brushless alternators having
single or three phase auxiliary supply.
The AVR should maintain constant voltage, irrespective of variation of load, cos φ, temperature,
moisture a.s.o.
It is fitted with a protection device enabling the alternator, adjusted for under frequency, to
continuously operate at frequencies under 50 or 60 Hz.
The selection of the regulated voltage range (110 V, 220 V or 380 V) is made by choosing the
connection of the AVR detection to detection
Note: - AVR6-V2 can be fitted with an outside potentiometer of 22 kΩ series connected with
the detection. It enables voltage adjustment of ± 5% for 380 V position, ± 10% for
220 V position and ± 20% for 110 V position.
- AVR6-V3 can be fitted with a current transformer enabling an offset characteristic
proportional to Isinφ.
- AVR6-V3 can be fitted with a potentiometer of 470 Ω. It can be also connected to an
AVR2 enabling the cosφ regulating when is connected to the mains.
II. FEATURES
Voltages and operation ranges at 50 or 60 Hz
min.
Terminals 380 V
≥ 330 V
Terminals 220 V
≥ 180 V
Terminals 110 V
≥ 95 V
max.
≤ 504 V
≤ 252 V
≤ 140 V
The impedance seen on the input terminals is equal to 0.4 kΩ per Volt. It takes 2W power at 500
V.
The voltage regulator operates normally at a frequency ranging between 48 and 63 Hz.
The resistance of the inductors must range between 5 Ω and 50 Ω.
Normally, the voltage detection is single-phase; adding the module AVR3-6 it becomes threephase detection; this module hinders the parallel operation of the machines by means of current
transformer; it doesn’t hinder parallel operation with the mains if coupled with AVR2.
2.1 PRIMING
The AVR is automatically started as soon as it is energized from an auxiliary supply exceeding 2
V at the frequency for which the current required by the alternator does not exceed the current
provided by the regulator.
The priming/starting of the regulator take place at a frequency only depending on the alternator
remanence (after effect-retentivity) and excitation needs. This is not a characteristic of the
regulator.
The regulator controls the alternator excitation according to desired curve as soon as the AVR
rectified supply voltage exceeds 20 V but is lower than 110 V.
These conditions feature a supply source that doesn’t exceed effective 60 V at upper limits of its
operation range.
2.2 VOLTAGE REGULATION UNDER STABILISED OPERATION/REGIME
The voltage is kept constant within ± 1% precision under the following conditions:
- during the temperature rise of the alternator and regulator
- ambient temperature between -300C and +65 Ω
- load variation between 0 and 4/4
- cos φ changing from 0.7 AR to 1
- frequency changing from 50 Hz to 60 Hz
- total harmonic content lower than 3%
- excitation voltage at least 2.5 V
If several conditions are simultaneous than the voltage precision is decreased additionally by ±
1%.
Under particular circumstances, when the temperature variations exceed 300C, the voltage
precision can be additionally decreased by another ±0.5%
2.3 VOLTAGE REGULATION UNDER TRANSITORY REGIME
2.3.1 Unsteadiness caused by the driving engine
The regulator has two damping possibilities (different gain and integration constant) adjustable
within a large band by means of a single potentiometer.
This enables the regulator to optimize its response in the following two situations:
- high cyclic irregularity of the Diesel engine
- The speed regulation of the Diesel engine little damped to the prejudice of the rapidity of
AVR response
2.3.2 TRANSITORY REGIMES
Reference voltage recovery time (final voltage) depends essentially on the reactances and time
constants of the alternator.
No-coupled strap – the regulation enables responses close to a second
Coupled strap – the regulation enables optimization of the response and final voltage recovery
time close to 0.2 sec.
2.4 THE VOLTAGE OF THE AUXILIARY WINDING
The rectified voltage of the auxiliary winding measured on the filter capacitor of the alternator
must not exceed 110 V under stabilized operation (regime).
Whenever the rectified voltage of the auxiliary winding exceeds 120 V a protection device
blocks up the excitation delivered by the voltage regulator (usually during transitory regimes).
The protection of the auxiliary windings: 2 fuses 6.3 A, rapid-acting 5x20, accessible on the
regulator.
2.5 VOLTAGE VARIATION AT LOW SPEED
The voltage regulator is fitted with a protection device when functioning at low speed. Beyond
the chosen threshold the regulator operates according to U/f = const. curve.
The regulator has two preset thresholds: one at 48 Hz and the second at 58 Hz. The changing
from one threshold to the other is made by connecting a strap to the FASTON terminals.
The extension of the line U/f = const. cuts off the ordinates at a voltage value equal to 5% of the
nominal voltage.
The voltage regulator is fitted with a low-speed breaking device (LAM). While the frequency
changes under 48 Hz or 58 Hz, after 0.7 sec. the voltage drops instantaneously to 90% of the
nominal value, on a new U/f = const. curve, two cases:
a) if the frequency gets back to the normal value in less than 3 sec. then the above cycle is
pursued in reverse direction.
b) the frequency remains under 48Hz and 58 Hz thresholds. The voltage gets back to U/f =
const. after 3 sec.
amorcage(fr)=start / kick off…
2.6 INSULATION
The insulation impedance between voltage detection, on one side and, the excitation terminals
and the supply source, on the other side is bigger than 1 M Ω at 500 V.
The dielectric voltage tests carried out for different windings of the alternator fitted with the
regulator can destroy partially or totally the regulator.
On the other hand an insulation resistance below 1000 Ω between the inductor and the supply
source can also destroy the regulator.
III. EXCITATION CHARACTERISTICS
- minimum no-load running voltage 2.5 V
- maximum direct voltage of the rectified auxiliary source 100 V
- nominal current 4 A at 400C
- peak maximum current 8 A
- resistance of inductors > 5 Ω
IV. INTERNAL PROTECTIONS OF THE REGULATOR
- the excitation current is limited to 8 A ± 0.5 A
- protection against short-circuits. The current is reduced in 10 sec. to a value
corresponding to an excitation voltage of about 15 V
- protection against cut detection wire: the current is brought back to the value
corresponding to an excitation voltage of about 15 V.
V. RADIO-ELECTRIC DISTURBANCES
If the regulator is placed inside the terminal box of the alternator, radio-electric disturbances
produced by its operation do not exceed N-class limits according to VDE and MIL STD 461B.
VI. ENVIRONMENT
The voltage regulator is suitable to be mounted on the alternator. It must be protected against
direct strokes. It is able to withstand ambient temperature between - 300C and +650C under
operation, - 550C up to +850C during storage, moisture of 100% with condensation, salt mist,
wind and sand action, shocks (9 gr., three-axes direction).
VII. VIBRATIONS
The voltage regulator can withstand vibrations levels depending on the vibrations allowed by the
electronic components (DIN NORMS).
VIII. SETTING
8.1 Stability – is adjusted by means of a potentiometer; if the potentiometer is turned clockwise
the regulator response is damped.
8.2 Voltage – is raised turning the potentiometer clockwise
8.3 Low-speed – preset by the supplier, this setting could not be changed excepting the changing
of the threshold from 50 Hz to 60 Hz by changing the position of the strap.
IX. CONSTRUCTION
- external connections by means of 10 terminal connector with insulation between
terminals, able to withstand 500 V between terminals.
- the regulator is inserted in plastic case of “NORYL” black, withstanding very large range
of temperatures
- the potentiometers are watertight
- semi-hard embedding material (SE 515 of G.E.) preventing the electronic components
from damages caused by vibrations.