OPERATING MANUAL FOR AUTOMATIC VOLTAGE REGULATOR
MODEL NO : EVC300i
Page 4 of 7
value (which is set using O/L POT), internal timer
starts and if overloading condition continues for 20
seconds then after 20 seconds AVR cuts off field
voltage and generator voltage is shut off. O/L LED
continues to light indicating O/L Trip. Adjustable from
0.1Amp to 7Amp DC. When O/L POT is fully
anticlockwise is minimum setting and fully clockwise
is maximum. Internal delay timer is fixed and delay
time is 20 seconds ±1%
To operationally test any EVC300i, refer to Figure 5
and perform the following steps:
a. Connect the voltage regulator as shown in Figure
5 and apply 230 Vac 50 Hz.
b. Adjust the rear panel
trimmer fully
clockwise (CW).
RESULT: Observe that the lamp lights up full.
c. Adjust the rear panel
trimmer fully counter-
clockwise (CCW).
RESULT: Observe that the lamp is not lit.
d. Adjust the rear panel
trimmer until the
lamp just goes out.
Regulator operation is satisfactory if the above
results are obtained. Stability, however must be
tested with the generator and regulator operating.
OPERATIONAL TEST
VOLT
VOLT
VOLT
From this position, rotate STAB POT anti-
clockwise direction till voltage is stable. Load the
generator and check for stable voltage and if not
then rotate more towards anticlockwise till voltage
is stable.
The EVC300i under frequency adjust is factory
preset to cause voltage drop in the generator
line voltage when the frequency is between 56.8
and 57.2 Hz for 60 Hz applications. For 50 Hz
applications, the frequency roll-off is factory preset
to between 46.8 and 47.2 Hz.
To reset the frequency roll-off, proceed as follows:
a. Adjust the prime mover RPM to the desired
frequency compensation (corner frequency roll-off)
point.
b. If UFRO LED is ON adjust the back panel
trimmer anticlock wise to just OFF the LED
If UFRO LED is OFF then adjust UFRO trimmer
clockwise to turn ON LED and then anticlockwise
to just turn it OFF.
c. Bring the prime mover up to rated speed. The
output voltage should return to set level.
Generator intended for parallel are fitted with a
quadrature droop CT which provides a power
factor dependent signal for the AVR. The CT
connected to
and
of AVR. CT with
secondary N:1A is required to provide minimum
10% droop at 0.8 PF. Percentage of droop
required can be adjusted using DROOP POT in
the range of 0 to 10%. Fully anticlockwise is 0%
and fully clockwise is maximum as per CT current
and load power factory. Factory set is 0% so that
mostly during solo operation there is no droop in
terminal voltage.
Trim Pot is used to decrease the effect of analog
input voltage on generator output voltage. When
set fully anticlockwise, there is no variation in
generator voltage on application of DC voltage on
A+ & A- Fully clockwise has maximum effect. Thus
using this POT we can get intermediate
percentage variation of the full scale - 10% at
± 5VDC.
.
Over load protection provides protection to
generator against overloading. It is based on field
current when field current increase above set
3. UFRO: Frequency Roll-Off Adjustment.
UFRO
4. DROOP: Droop Adjustment.
S1
S2
5. TRIM: Analog Voltage Input Adjustment.
6. O/L : Over Load Protection
Updated on 02 Feb2015
