Egcon AVR-126 User manual

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AUTOMATIC VOLTAGE REGULATOR
(MODEL : AVR-126)
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WARNING :
To prevent personal injury or equipment damage, only qualified technicians /operators
should install, operate or service this device.
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CAUTION :
Megger and high potential test equipment should not be used.
Incorrect use of such equipment could damage components contained in the regulator.
1. APPLICATION : AVR 125 is voltage regulator
to control brushless generator output by regulating
the current into the generator exciter field.
2. FEATURES :
2.1. Available for low resistance exciter filed.
2.2. Under frequency protection circuit.
When the generator frequency drops below the set point, generator output voltage is decreased with
the curve proportional to the frequency.
2.3. Over excitation
When the generator excitation field voltage exceeds 85Vdc, AVR output shut down to protect the
generator winding coil from burning out.
2.4. Starting engine generator set, if the residual voltage remains on the stator winding of generator,
AC output voltage is built up rapidly.
2.5. Durable under dust, damp and vibration.
2.6. Response time, below 25ms(1.5cycles)
3. SPECIFICATIONS
3.1. Input : 190~277Vac, 1 Φ , 50/60Hz, Burden 650VA (terminal 3-4)
3.2. Output :
MODEL VOLTAGE CURRENT REMARKS
AVR - 125 125Vdc 15A continuous
Maximum current (for 1min.) - 20A
3.3. Sensing : 1 Φ ,190 ~ 240Vac (220V sensing – terminal 4-3)
1 Φ ,380 ~ 400Vac (380V sensing – terminal 4-E1)
3.4. Exciter field resistance : 2ohms to 100ohms
3.5. External voltage adjust rheostat : 1 ㏀ , 2W (out of supply scope)
3.6. Voltage adjust range
Coarse adjusting (by internal rheostat) ± 12.5%
Fine adjusting (by external rheostat) ± 5%
3.7. voltage regulating accuracy ± 1.0%
3.8. Voltage build up condition internally and automatically raised by the residual voltage from the
Generator stator winding (minimum 3Vac)

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3.9. Over excitation shut down : when exciter field voltage exceeds the following, AVR output is
removed. Otherwise, exciter field voltage keeps on over 85 ± 5Vdc for 10sec, or instantaneously
it exceeds 100Vdc.
After shutdown, to reset the regulator, generator set should be stopped or the power input to the AVR
Should be interrupted for more than 20seconds.
3.10. Operating temperature : -20 ℃ (-8 ℉ ) to 50 ℃ (140 ℉ )
3.11. Storage temperature : -40(-40 ℉ ) to 85 ℃ (185 ℉ )
4. STRUCTURE
4.1. Size : W140 x H200 x D60(mm)
4.2. Mounting size : W90 x H190(mm) x 5 Φ - 4Holes
4.3. Color : bottom and cover - ivory
4.4. Frequency selection : changeover switch
4.5. Weight : about 2kg
5. INSTRUCTION AND CONNECTION
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● NOTE
Prior to mounting the regulator, generator manufacture should check whether regulator
output current meet the capacitor of exciter.
5.1. Mounting
See above diagrams for mounting AVR in the generator conduct box or the generator control and
Switch gear.
It is recommend that AVR be mounted with the front panel to be showed all marks straight and
easily in the vertical plane.
5.2. Connection
Refer to the following drawings for the correct connection.

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▶ Remote voltage adjust
Remove the jumper from the terminal 6 and 7, and connect the remote voltage adjust
potentiometer (rheostat) to the terminals 6 and 7 as specified.
▶ Sensing voltage
Generator voltage sensing is single-phase 220Vac or 380Vac.
It can be selected in accordance with generator output voltage (or rated voltage)
as follows,
*380V sensing (terminal 4-E1) ; As generator output voltage is380, 400 and
440V ,415V
*220V sensing (terminal 4-3) ; As generator output voltage 208, 220 and 230V
▶
Power input
The power input terminal of the regulator are marked power input AC 220V
▶ Power output
The two power output terminals of the regulator are marked F+, F-
These two lines are connected to the F+, F- (or J, K) of exciter field respectively.
6. ADJUSTING
6.1. Start prime mover and bring up to rated speed.
6.2. Voltage would be automatically built up.
If not, confirm until voltage build up through the DC power connection to directly the J,K terminal
of generator ,with BATT. (+) and BATT, (-) under disconnecting lines F+ and F- from the regulator.
6.3. If a minimum residual of 3 VAC is not present, perform field flashing by using 12Vdc battery and
Contactor as below drawing. Please refer to 7.FLASH EXCITING. for details.
6.4. Adjust volt potentiometer until voltage reaches nominal value.
▶ Coarse voltage adjustment
: internal rheostat, single turn
▶ Fine voltage adjustment
: external remote rheostat, single turn, set point should be mid position to notice easily
6.5. Adjust for stab potentiometer if voltage is unstable.
(Adjusting stability changes the response time of regulator,

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▶ turning CW increase the level for damping generator transient output voltage.
▶ turning CCW decrease damping level to cause under damping
6.6. Choice frequency switch depending on generator frequency (SW1)
This option protects generator and AVR by decreasing generator output voltage if it reduces
generator frequency. (under frequency protection)
- Frequency 50Hz system (refer to below 50Hz system)
- Frequency 60Hz system (refer to below 60Hz system)
43 5045 48 Hz
rated volt
residual volt
output volt
residual volt
output volt
rated volt
5553 58 60 Hz
(V) (V)
(60Hz System)(50Hz System)
7. FLASH EXCITING
7.1. MANUAL FIELD FLASH ESCITING
When generator does not build up to the rated value or has no output, manual field flash exciting
could be executed as the following order. Please refer to the below drawing.
1) Remove two output lines connected to the terminals J, K of generator.
2) Prepare a12Vdc battery and a push button ,and connect them as the drawing.
3) Start engine
4) When the revolution is reached rating, push the button for short time (about 1~2sec)
5) Check the output voltage.

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6) Stop the engine and remove battery and push button.
7) Reconnect all wires.
8) Start engine and check the output voltage.
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● NOTE
To take flash exciting without engine running, keep the button on a pushed condition to
close the flash exciting circuit for 30sec.
7.2. AUTOMATIC FILED FLASH EXCITING
Whenever start generator set, to avoid no output voltage. It is recommended to take automatic
field flash exciting by using the generator control sequence as below drawing.
 
  
 
 
8. PARALLE OPERATION
AVR 125 are not designed for parallel operation ,but connecting a external variable resistance with a
toggle switch as below drawing, in series with one line of two input sensing lines to the regulator, the
the regulator can run in droop performance for inductive load.

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 
 
  
 
9. TROUBLE SHOOTING
SYMPTOM CAUSE ACTION
Residual Voltage-
No Output
Residual voltage at regulator
power input wires 3 & 4 below 3Vac.
Field leads F+, F- not connected.
Power input leads not connected.
Blown or missing fuse.
Defective regulator.
Defective generator.
Check wiring diagram for proper
Connections.
Flash generator field. Refer to 7.FLASH
EXCITING section in generator manual.
Connect field lead F+, F-.
Connect power input leads 3, 4.
Replace fuse.
Replace regulator.
Consult generator manual.

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Output Voltage Low
Incorrect connections.
Voltage adjust turned down.
Remote voltage adjust is turned down.
Defective regulator.
Check wiring diagram for proper
connections.
Incorrect sensing voltage connection can
cause output voltage low-no adjustment.
Rotate voltage adjust CW until desired
voltage is reached.
Rotate remote voltage adjust CW until
desired voltage is reached.
Replace regulator.
Output Voltage High
Voltage adjust turned too high.
Remote voltage adjust is turned too
high
Rotate voltage adjust CCW until desired
voltage is reached.
Rotate remote voltage adjust CCW until
desired voltage is reached.
Output Voltage High-
No Adjustment
Defective regulator. Replace regulator.
Rating Output
Voltage at no load and
Voltage Down at load
condition
Generator defective Check the generator exciter and rotating
diode
Remote voltage Adjust
Operates backwards
Voltage adjust wire backwards. Reverse the wiring of the connection on
the remote voltage adjust.
Generator Output
Voltage Hunting
Defective regulator Rotate the stability adjust in a CW
direction until hunting stops
Poor Regulation Defective regulator. Replace regulator.