Automatic Voltage Regulator
Compatible with Leroy Somers R448*
For Use with PMG, AREP and Auxiliary Winding Generators
Operators Manual
* Used for reference only this is not a genuine Leroy Somers product
SPECIFICATIONS
Normal AVR supply power: 2 auxiliary windings Generator output voltage is adjusted by using the
(X1, X2, and Z, Z2)
voltage adjustment potentiometer on the AVR
Shunt supply : 150V - 50/60Hz
Rated overload current: 10A, 10s.
Electronic built-in (overload, short circuit, and loss of
sensing) protection: If excitation current raises over 10
Amps for more then 10 seconds, excitation current will
drops automatically to about 1A.
To reset AVR protection, generator must be stopped (or
by cutting supply voltage to the AVR).
Power factor regulator (2nd function) and voltage
equalization before paralleling with the mains (3rd
function)
CT xxx/1 A. 5VA CL1
Module R 724: 2 functions.
Module R 725 A: 3 functions.
EMI suppression
Protection of power inputs by fuses F1
(*)Note: For a wider voltage adjustment range and 1 k
ohm/3W pot may be used.
Voltage sensing: 5VA insulated transformer with input
voltage taps at:
The R 730 module is not compatible with paralleling.
Terminals 0-110V = 95 to 140V
Terminals 0-220 V = 170 to 260 V
Terminals 0-380 V = 340 to 520V
Output Voltage adjustment by using pot P2
Other sensing voltages by using an adapting other
transformers
Current sensing (parallel operation) CT 2.5 VA class 1
secondary current xxx/1 (optional).
Adjustment of quadrature droop with pot P1
Under-speed (U/F) and LAM protection: for knee
frequency adjustable use P4.
Special applications
Field de-energizing
Cutting excitation current is accomplished
by
switching off the supply power to AVR (1 lead on each
auxiliary winding)
Contacts capacity: 10A. 250V AC
This is the same connection used to reset internal
protection of AVR.
Static test AVR
* Testing the A.V.R. by using a static test does not
necessarily mean it can operate properly.
Excitation over current adjustment use P5: 4.5 to 10A
* But inversely, if the A.V.R. does not test properly
during static tests, it is obviously defective
For 50/60 Hz (U/F) selection use jumper ST3.
Setup the test (see drawing).
Load acceptance module
Supply voltage must be 100 to 140V and the light bulb
must be rated for 220v use you can also use 2 x 110v
bulbs in series.
LAM is suppressed by cutting wire marked ST5
LAM (Load Acceptance Module) function.
When applying a step load to the generator, the
rotational speed (frequency) of the genset drops. If the
speed is below the preset frequency, the "LAM" circuits
drops the voltage about 15% and this way reducing the
effective step to about 25%, as long as the speed has
not recovered to normal values.
The "LAM" is used either to reduce the speed drop
of the engine, during the step load, or to increase
the applicable step load for the same speed
variation (turbo charged engines) so the engine can
recover normal speed quickly.
To prevent voltage oscillations, the frequency threshold
must be adjusted about 2 Hz below the lowest
frequency in normal operation.
Optional items for use with the AVR
CT for parallel operation with other generators
Remote voltage adjusting potentiometer 470 ohm .3W
(*) giving an adjustment range of +/- 5% (centering of
the range by using internal P2 potentiometer). Remove
wire ST4 to connect external potentiometer.
Three phase sensing available by using additional
modulo Model R 730:200 to 500V. Cut ST1 to connect
this module.
Total lamp load must not exceed 100 Watt
1) - Adjust AVR voltage by moving screw P2 to
maximum CCW position
2) - Apply power to the AVR the lamp should flash
momentarily and turn off.
3) - Slowly rotate the AVR voltage screw clockwise:
The bulb will slowly light up and reach full brilliance
before P2 is moved completely clockwise, at the
regulating point a small movement back and forth with
P2 will turns the bulb on and off. If the lamp remains
constantly on/off the AVR is defective.
Repeat the test supplying AVR power through terminals
XI, X2, and then test again by supplying power through
terminals Z1, Z2.
Static test LAM
(under-speed protection)
Voltage adjustment Pot P2 should be set in it normal
position just when the lamp just begins to glow. Turn P4
slowly CCW the brightness should decrease suddenly
the voltage at AVR's output terminals E+, E- must falls
about 15%. Then resetting P4 to initial position : the
lamp should glow normally as before
Adjustment procedure
- By adjusting engine speed, reduce power exchange,
to 0 KW
a) Initial setting of potentiometers
- P3 STABILITY: middle position.
- By adjusting voltage pot (P2 or Rhe) on one of the
machines try to cancel (or minimize) circulating
currents.
- PI QUADRATURE VOLTAGE DROP : fully CCW
- Do not change voltage adjustments.
- P5 EXCITATION CURRENT LIMIT: to be adjusted
only if necessary maximum fully CW.
n) Switch on the load (adjustments cannot be made if
there is no reactive load).
- Remote voltage trimmer Rhe - 470 OHM (jumper ST4
removed): middle position.
- By adjusting speed, balance the KW (proportionally to
the rated powers of each genset).
b) Connect one analog (needle type) voltmeter cal. 50V
D.C. across E+, E-terminals and another (300V-500V or
1000V) A.C. across the alternator output terminals.
- By adjusting voltage droop with pot. P1, balance the
output currents.
- P2 VOLTAGE: lowest fully CCW.
c) Make sure that the 50/60 Hz link is correctly
connected
d) (P2) potentiometer
anti-clockwise
must
be
set
maximum
e) (P4) (V/Hz) must be set maximum clockwise
f) (P3) (Stability) has to be adjusted maximum
clockwise -1/3.
g) Start and adjust the engine speed corresponding to
48Hz for 50 Hz (nominal) or 58 for 60 Hz.
h) Adjust output voltage with (P2) to the required value
- rated voltage UN if generator operates alone
(for example 400V)
-or UN+2 to 4% for parallel operation with CT
(i.e. 410V - see below)
If voltage is unstable, adjust (P3) (try in both
directions), noting voltage across E+, E- (approx.1OV
dc) The fastest recovery time may be achieved when
(P3) is set close to the limit of instability. If there is no
stable position try adjustment again after having cut or
reconnecting link ST2 (normal / fast).
i) Turn (P4) anticlockwise until the voltage drops about
15%
Adjustment of maximum
current
(Excitation ceiling)
excitation
- Static adjustment of excitation current limitation,
potentiometer P5 (factory adjustment: 10 A, fuse
caliber: 10A-10seconds).
The factory adjustment corresponds to the excitation
current for a sustained 3 phase short circuit, of about 3
times the rated current, unless otherwise specified(*)
It is possible to reduce the maximum excitation level by
a static method which is safer for the alternators and the
network.
Disconnect the supply leads (XI X2, Z1, Z2) and
sensing leads (0-110-220-380) on the AVR. Connect
the supply as shown (XI, X2, 0,110V). Connect an
ammeter (10A, dc) in series with the exciter field. Turn
P5 fully CCW. Switch on the supply. If there is no output
current from AVR, turn P2 (voltage) clockwise until
ammeter indicates a stabilized current.
Switch the supply off, then on again. Turn P5 clockwise
until the required current is obtained in the exciter field,
(limit to 10A)
Checking internal protection:
j) Modify engine speed around 48 or 58 Hz in order to
check the LAM voltage drop (~ 15%).
Switch off (B): the excitation current must rise to the
pre-set high level, and remain at this level for a period
of more than 10 seconds, than fall to less than 1A.
k) Readjust speed of genset to its normal no-load level
To reset, switch off the supply by opening switch (A).
ADJUSTMENTS IN
PARALLEL OPERATION
Note: Preliminary to any adjustment on the AVR, make
sure that engine speeds are similar.
l) Presetting for parallel operation (with CT connected to
terminals S1 ,S2 of terminal strip J2)
- Potentiometer P1 (Voltage droop) in middle position.
Switch on the rated load (P.F. 0.8 inductive). The output
voltage should drop 2% to 3%. If voltage rises, reverse
the 2 leads from the CT.
m) No load voltages must be identical on all gensets
working together and in parallel.
- Synchronize and parallel the gensets together.
Note: After having adjusted the excitation current
limitation
(*): In many countries short-circuit current equal to 3
times IN is obligatory in order to allow selective tripping
of circuit breakers.
ST3
LED
Fuse 10A
50HZ
60HZ
P5
J1
Z1
J2
X1
X2
P4
X2
Z1
X1
Z2
E+
E0V
110V
220V
380V
Z2
E+
ST2
E-
P3
0V
110V
ST6
220V
ST7
380V
P2
S2
S1
VR
VR
ST1
P1
3ph in
S2
S1
1k
3ph in
50HZ
ST4
60HZ
X2
P5
Mains
Z1
LED
(Supply 50/60Hz)
X1
P4
Frequency
Z2
E+
SS448
Vlotage
E-
P3
0V
110V
VM
220V
VR
VR
P2
380V
300Vdc
S2
S1
220V
P<100W
VR
1k
3ph in
3ph in
Static test AVR
Mains
(Supply 50/60Hz)
Excit max
50HZ
60HZ
X2
P5
Z1
LED
X1
P4
Z2
SS448
P3
Excite
eld ~6 ohm
E+
E0V
110V
Voltage
P2
220V
VR
VR
380V
3ph in
S2
S1
VR
1k
3ph in
Ad justment of maximum excitation current
11
Red
9 Green
Set according to voltage
Using the EA448 in place of the Marathon DVR 2000
DVR2000E (digital AVR) provides 7.5A 150VDC Max output short time in compareson to model EA448
(Analog AVR) thats provide 10 A 160VDC Max output short time
Both model use power FET driven outputs and use PWM (pulse width modulation) depending on excitation
The both have over-voltage and over-current protections
The biggest difference is Model DVR2000E is 3-phase sensing and Model EA448 is single phase sensing.
In addition, Model AVR2000E has Binary inputs for remotely voltage adjustment and Model EA448 has
conventional remote potentiometer adjustment.
Exciter field
Armature
C.T.
Stator
480/277v
XX/1A
E1
U
7.5MF
PMG
W
200VAC max 50 to 500 Hz
Fuse 10A
50Hz
60Hz
AVR EA448
X2
Z1
X1
Z2
E+
EOV
110V
220V
380V
S2
S1
EXT VR 1k Ohm
E2
R
S
T
