Nidec LEROY-SOMER R120 Instruction Manual

V S UF OPEN IN 60Hz OE UF SL
V N1 U N F1 F2
R120
R120
AVR
Installation and maintenance

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R120
AVR
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SAFETY MEASURES
Before using your machine for the rst time,
it is important to read the whole of this
installation and maintenance manual.
All necessary operations and interventions
on this machine must be performed by a
qualied technician.
Our technical support service will be pleased
to provide any additional information you
may require.
The various operations described in this
manual are accompanied by recommenda-
tions or symbols to alert the user to potential
risks of accidents. It is vital that you unders-
tand and take notice of the following warning
symbols.
Warning symbol for an operation capable
of damaging or destroying the machine
or surrounding equipment.
Warning symbol for general danger to
personnel.
Warning symbol for electrical danger to
personnel.
All servicing or repair operations perfor-
med on the AVR should be undertaken by
personnel trained in the commissioning,
servicing and maintenance of electrical
and mechanical components.
When the generator is driven at a
frequency below 28 Hz for more than 30
seconds with an analogue AVR, its AC
power supply must be disconnected.
WARNING
This AVR can be incorporated in a EC-
marked machine.
This manual is to be given to the end
user.
© - We reserve the right to modify the
characteristics of this product at any time in
order to incorporate the latest technological
developments. The information contained in
this document may therefore be changed
without notice.
This document may not be reproduced in
any form without prior authorisation.
All brands and models have been registered
and patents applied for.
WARNING
This manual concerns the alternator AVR which you have just purchased.
We wish to draw your attention to the contents of this maintenance manual.

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CONTENTS
1 - GENERAL DESCRIPTION.................................................................................................4
2 - OPERATION OF THE AVR.................................................................................................4
3 - TECHNICAL SPECIFICATION...........................................................................................5
4 - MAIN FUNCTION OF THE AVR .........................................................................................6
5 - AVR SETTINGS..................................................................................................................7
5.1 - V-TRIM (V) ...................................................................................................................7
5.2 - FRO (UF) .....................................................................................................................7
5.3 - STAB (S) .....................................................................................................................7
6 - AVR CONTROLS................................................................................................................7
7 - TROUBLESHOOTING CHART..........................................................................................8
8 - MULTIMETER CHECKS ....................................................................................................9
9 - STATIC TEST PROCEDURE ...........................................................................................10
10 - DIMENSIONS.................................................................................................................12
11 - SPARE PARTS ............................................................................................................... 13
11.1 - Designation ..............................................................................................................13
11.2 - Technical support service .........................................................................................13
Disposal and recycling instructions

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1 - GENERAL DESCRIPTION
The R121 automatic voltage regulator
(AVR) is a compact, high-performance
encapsulated unit. It incorporates the latest
technology and efcient components to
achieve a high degree of miniaturisation
when used with 3-phase and 1-phase AC
brushless generators within its input and
output limits. The unit offers excellent
reliability.
The AVR provides DC excitation to the
exciter eld of a brushless generator to keep
the voltage within the approximate operating
limits from NO-LOAD to FULL LOAD.
The typical recovery time in the event of
sudden loading is around 0.5 sec. to recover
98% of the rated voltage. Transient
performance such as voltage dip and
recovery time is mainly determined by the
generator and exciter design parameters.
Optimum AVR performance can be
obtained by keeping full-load excitation to
around 60 VDC.
The generator uses a true average sensing
circuit, dV/dt snubber and special lter
circuits to manage NON-LINEAR loads
such as battery chargers, DC motors, etc.
Voltage regulation is only guaranteed for
linear loads. Severely distorting NON-
LINEAR loads can cause regulation
problems.
Each AVR is tested prior to dispatch as part
of a quality plan, for standard voltage and
frequency.
Asoft-start circuit is included which provides
smooth control of the build-up of generator
output voltage.
A frequency roll-off circuit continuously
monitors the generator underspeed
protection by reducing the generator output
voltage in proportion with the speed below a
threshold.
2 - OPERATION OF THE AVR
The AVR is powered by the line-to-neutral
terminal of the AC generator, with 240 VAC
rms at 50 Hz or 60 Hz. The sensing voltage,
which is the regulated voltage, is based on
line-to-line (for 3-phase) and line-to-neutral
(for 1-phase). The AVR forms an important
part of the closed loop system comprising
the generator eld, generator armature and
the AVR.
The AVR rst builds up the generator voltage
from its residual levels, to the rated value of
415 V for 3-phase and 240 V for 1-phase.
When the generator is loaded, the sensed
voltage decreases and generates an error
voltage, which is required in order for the
closed loop system to work.
The AVR contains a high gain amplier,
ramp and a pedestal circuit. Depending
upon the value of the amplier voltage
(either high or low) the ramp intersects the
amplied voltage at a point, which is either
early or late in the half-cycle. At this
intersection point a starting pulse is
produced to trigger the power device.
When the power device is triggered early in
the half-cycle, more voltage is transmitted to
the eld and when triggered late in the half-
cycle, less voltage is transmitted to the eld.
In order to reduce the generator voltage at
low speed, a signal inversely proportional
to the speed is generated as an extra input.
At higher speeds the voltage decreases at a
faster rate than in proportion with the speed.

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3 - TECHNICAL SPECIFICATION
1) Sensing input
- Voltage: 277 VAC ± 10% for 1-phase,
415 VAC line-to-line ± 10% for 3-phase,
2-line sensing. The AVR senses the true
average of the line-to-line waveform. Use
the resistor (SMD) network for trouble-free
sensing and control of sensed voltage/
regulation.
2) Input power
- Voltage: 277 VAC rms ± 10%
- Frequency: 50/60 Hz
3) Output power
- Voltage: 95 VDC for 240 VAC Input
- Current:
• 4 A DC
• 6 A for 30 sec. (when allowed by the eld
resistance)
4) Operating temperature: -20ºC to +70ºC
5) Storage temperature: -40ºC to +80ºC
6) Voltage setting: min ± 10% of rated
voltage.
7) Stability setting: can be adjusted to obtain
a correct transient response in steady state.
8) Under frequency roll-off setting: available
below 46 Hz for 50 Hz and below 56 Hz for
60 Hz.
9) Voltage build-up: 2 Volts (L-N)
10) Voltage regulation: ± 1% at the AVR
terminals with a THC <5%.
11) Thermal drift: ± 1% for 30ºC change in
temperature.
12) Response time: less than 50 ms.
13) Closed loop response: typically 0.5 sec
to recover 98% of the dened voltage for a
eld forcing ratio of 1:2.
14) Sensing loss protection: the voltage
should disappear when the sensing circuit is
open.
15) Overexcitation protection set point:
85 VDC.
16) Protection fuse: 4 A, 240 VAC.
17) Potentiometer sealing: except for the
V-trim potentiometer, all potentiometers are
sealed.
18) Frequency roll-off indicator: LED
provided (UF).
19) Sensing loss indicator: LED provided
(SL).
20) Overexcitation indicator: LED provided
(OE).
21) Protection on the devices: suitable R-C
snubber to be provided for the device used
to protect against voltage surges.
22) Potting/Encapsulation details: the
components on the AVR should be
completely encapsulated with suitable PU
resin compound to absorb transients/
vibrations during operation.
23) Alternator excitation details: (typical)
- Full load:
• Excitation voltage: 40 to 50 V
• Excitation current: 2.5 to 4.0 A
24) Terminal marking: see diagram
25) Dimensions:
- Overall: 104 x 94 x 40 (mm)
- Mounting: 83 (mm)
- Mounting hole dia: 5.5 (mm)
26) Weight: 185 g

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4 - MAIN FUNCTION OF THE AVR
The AVR is powered by the line-to-neutral terminals of the AC generator with 240 VAC at
50/60Hz.The regulated sensing voltage is based on the AVR input power.
T1
U1
T4
U2
T3
W1
T6
W2
T2
V1
T5
V2
SL
OE
V S UF OPEN IN 60Hz OE UF SL
V N1 U N F1 F2
S
U/F
50 Hz
60 Hz
*
V
UF
MAIN FIELD
Armature
Exciter field
Varistor
STATOR: 6 wires (T1 to T6 identification)
* Note: for delta configuration (1PH – 3PH), use terminals N and U, short N and N1.
Sensing loss
Over-excitation
Voltage
Stability
Fuse 4 A
240 V
Under
frequency
Frequency
* not connected in delta configuration
yellow
green
blue
Star configuration
Delta configuration
black
red

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The AVR builds up the generator voltage
from its residual voltage to rated voltage.
When the generator is loaded, the sensed
voltage decreases and generates an error
signal, which is required in order for the
closed loop system to work.
Depending upon the value of the amplied
voltage, the ramp intersects the amplied
voltage at a point which is early or late in the
half-cycle.
At this intersection point, a starting pulse is
produced to trigger the power device.
Only qualied personnel should replace/
work on the AVR.
Do not increase the voltage beyond the
rated voltage.
5 - AVR SETTINGS
5.1 - V-TRIM (V)
This function is provided for setting the
voltage up to ± 10% of rated voltage by
means of a potentiometer.Turn the
potentiometer clockwise to increase the
voltage and vice versa, once the rated
speed has been reached.
The default setting is 415 V ± 2% for
3-phase, 240 V ± 2% for 1-phase.
5.2 - UNDER FREQUENCY KNEE
POINT SETTING (UF)
This function is provided to protect the AC
generator from sustained low speed
operation through a potentiometer. TheAVR
will reduce the voltage in proportion with the
speed below the dened value.
The procedure for setting the UF
potentiometer is as follows:
First run the generator at full speed (50 Hz)
and turn UF by a few turns clockwise,
making sure that the voltage does not
increase. Now turn the UF potentiometer
slowly anticlockwise. At a particular point
the red LED glows and the voltage will start
to decrease. Stop turning the potentiometer
at this point and turn the potentiometer
clockwise by two turns after rated voltage is
restored.
The factory default setting is 46 Hz.
5.3 - STAB (S)
This function is provided to stop voltage
hunting by means of a potentiometer. Turn
clockwise to increase stability (to stop
oscillation). Turning too far clockwise will
result in a sluggish response and possibly
also oscillations.
The factory default setting is slightly
higher than critical damping (around
halfway).
6 - AVR CONTROLS
No. Control Function Direction
1 VOLTS Sets the generator output voltage Turn clockwise to increase output voltage
2 STAB Stops voltage hunting Turn clockwise to increase stability
3 UFRO Sets the Under frequency
knee point
Turn clockwise to to reduce the knee
point

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7 - TROUBLESHOOTING CHART
Symptom Cause Action
No voltage
build-up
Fuse blown Check and replace
Low residual voltage across U
and N terminals
If the generator’s residual voltage at rated speed
is less than 2.5 VAC (L-N), disconnect the AVR
and connect a 24 VDC battery, keeping F1 as
positive and F2 as negative.
Connecting a freewheel diode (BY 127) across
the eld with the diode cathode to F1 and the
anode to F2 during eld ashing will help restore
the residual voltage.
WARNING:
Remove the diode (BY-127) after eld ashing.
The 24 V battery positive terminal must only be
connected to F1 and the negative to F2.
Swapping the connection will cause diode BY127
to explode instantly.
Incorrect wiring Check wiring
Rotating diodes and/or fuse
failed
Check and replace
Voltmeter on the front
defective
Check and correct
AVR defective
(repeated fuse blowing)
Replace after performing a static test
Earthed exciter eld Check and correct
High voltage
build-up
Loose or missing connection
to AVR U terminal
Check and correct
AVR defective Perform a static test and replace if necessary
Low voltage
build-up
Low prime mover speed Check and correct
Sensing loss in circuit Check and correct
AVR defective Replace the AVR
Voltage oscillation Incorrect stability
potentiometer sealing
Turn clockwise until hunting stops
Prime mover speed hunting Check and adjust the controller
Load hunting, uctuates
rapidly
Check and correct
High percentage of non-linear
loads
Check and reduce the non-linear load
High reactance in generator
(during non-linear loading)
Consult the generator manufacturer
Incorrect
regulation
The exciter eld’s requirement
is higher than 95 VDC
Wrong selection or very low P.F. load. Check and
correct.
Prime mover speed drops too
much when on load (kW load)
Adjust the controller and reduce the active load

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8 - MULTIMETER CHECKS
Equipment: Digital multimeter, Type:
MECO or equivalent.
Select Diode mode on the digital multimeter.
The resistance between F1 and F2 (with the
multimeter jack common applied to F1 of the
AVR) should be between 0.4 and 0.6 kΩ,
and vice versa (with the multimeter jack
common applied to F2 of the AVR) should
give INFINITY.
ZERO indicates a power device failure in
both cases, No further tests (static or
dynamic) are allowed, as they would lead to
the fuse blowing.
The resistance between F2 and U (both
sides) should be 180 kΩ.
The resistance between F2 and V with the
multimeter jack common applied to the AVR
V terminal should be approximately 2.2 MΩ
in the 10 MΩrange and vice versa (with the
multimeter jack common applied to the AVR
F2 terminal) should be 15 MΩ.
ZERO indicates a power device failure in
both cases, No further tests (static test or
dynamic tests) are allowed, as they would to
the fuse blowing.
The resistance between U and V should
be between 300 kΩand 400 kΩ. Open
circuit indicates AVR failure. During a static
test, the lamp will not turn OFF or, when
connected to the generator, it will produce a
ceiling voltage (for 3-phase ONLY).
The resistance between U and N1 should be
between 200 kΩand 260 kΩ. Open circuit
indicates AVR failure. During a static test,
the lamp will not turn OFF or, when
connected to the generator, it will produce a
ceiling voltage (for 1-phase ONLY).
The resistance between N and F1 should be
very low or ZERO ohms. If the circuit is
open, the lamp will not glow when the static
test is performed.

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9 - STATIC TEST PROCEDURE
For 3-phase circuit
This test should only be attempted after
making sure that the AVR has passed all
multimeter checks. Connect the AVR to the
three-phase variable voltage source as
shown in diagram 3 in this manual.
1. Keep ‘V-TRIM’ in the minimum position.
2. Keep UF in the fully maximum position.
3. Increase the applied voltage. The lamp
should glow increasingly brightly. At a
voltage of around 360-380 V the lamp
should go out slowly. Increase the voltage
again up to 415 V. The lamp should stay
OFF.
Decrease the voltage to below 360 V. The
lamp should glow brightly again.
4. Turn the UF potentiometer anticlockwise;
the lamp should go out slowly. Now turn the
UF potentiometer clockwise. The lamp
should glow brightly again.
5. It is difcult to prescribe a static test for
checking the stability, as this is more easily
detected during closed loop tests. However,
a healthy AVR will behave as described
below.
First keep the ‘STAB’ potentiometer in the
fully anticlockwise position. Perform the
static test as described in steps 1, 2 and 3.
The lamp will go out fairly quickly at 360-
380 V and come on again quickly when the
voltage is reduced to below 360 V.
Now keep the ‘STAB’ potentiometer fully
clockwise, and perform the static test as in
1, 2, and 3. The lamp should go out much
more slowly and come on again much more
slowly. At the end of this test reset the
potentiometer in the middle position.
If the AVR behaves as described above
then it is in good working order.
AVR (3PH)
Model: R120
LAMP
100 W
230 V
VAC
0-500 V
STATIC TEST CONNECTION DIAGRAM OF 3PH AVR
415 V, 3PH, 50 Hz,
WITH NEUTRAL
VARIAC
8A, 415 V

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For 1-phase circuit
This test should only be attempted after
making sure that the AVR has passed all
multimeter checks. Connect the AVR to the
single-phase variable voltage source as
shown in diagram 1 in this manual.
1. Keep ‘V-TRIM’ in the minimum position.
2. Keep UF in the fully maximum position.
3. Increase the applied voltage. The lamp
should glow increasingly brightly. At a
voltage of around 200-220 V the lamp
should go out slowly. Increase the voltage
again up to 240 V. The lamp should stay
OFF.
Decrease the voltage to below 200 volts.
The lamp should glow brightly again.
4. Turn the UF potentiometer anticlockwise;
the lamp should go out slowly. Now turn the
UF potentiometer clockwise. The lamp
should glow brightly again.
5. It is difcult to prescribe a static test for
checking the stability, as this is more easily
detected during closed loop tests. However,
a healthy AVR will behave as described
below.
First keep the ‘STAB’ potentiometer in the
fully anticlockwise position. Perform the
static test as described in steps 1, 2 and 3.
The lamp will go out fairly quickly at 200-
220 V and come on again quickly when the
voltage is reduced to below 240 V.
Now keep the ‘STAB’ potentiometer fully
clockwise, and perform the static test as in
1, 2, and 3. The lamp should go out much
more slowly and come on again much more
slowly. At the end of this test reset the
potentiometer in the middle position.
If the AVR behaves as described above
then it is in good working order.
AVR (1PH)
Model: R120
LAMP
100 W
230 V
VAC
0-300 V
230 V, 1PH, 50 Hz,
WITH NEUTRAL
VARIAC
8 A, 230 V
STATIC TEST CONNECTION DIAGRAM OF 1PH AVR

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10 - DIMENSIONS
94 mm
104 mm
52 mm
82 mm
V
VN1 U N F1 F2
SUF OE UF SL
OPEN IN 60Hz
FUSE
R120
2 x holes Ø 5.5
x 83 mm

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11 - SPARE PARTS
11.1 - Designation
Description Type Code
AVR R120 4969966
11.2 - Technical support service
Our technical support service will be
pleased to provide any additional
information you may require.
For all spare parts orders or technical
support requests, send your request to
[e-mail] or your
nearest contact, whom you will nd at
www.lrsm.co/support indicating the type
and the code number of the AVR.
To ensure that our products operate correctly
and safely, we recommend the use of
original manufacturer spare parts.
In the event of failure to comply with this
advice, the manufacturer cannot be held
responsible for any damage.

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Disposal and recycling instructions
We are committed limiting the
environmental impact of our activity. We
continuously monitor our production
processes, material sourcing and products
design to improve recyclability and minimise
our environmental footprint.
These instructions are for information
purposes only. It is the user’s responsibility
to comply with local legislation regarding
product disposal and recycling.
Waste & hazardous materials
The following components and materials
require special treatment and must be
separated from the alternator before the
recycling process:
- electronic materials found in the terminal
box, including the automatic voltage
regulator (198), current transformers (176),
interference suppression module and other
semi-conductors.
- diode bridge (343) and surge suppressor
(347), found on the alternator rotor.
- major plastic components, such as the
terminal box structure on some products.
These components are usually marked with
information concerning the type of plastic.
All materials listed above need special
treatment to separate waste from
reclaimable materials and should be
entrusted to specialist recycling companies.

[e-mail] www.lrsm.co/support
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Our worldwide service network of over 80 facilities is at your service.
This local presence is our guarantee for fast and e󰀩cient repair, support and
maintenance services.
Trust your alternator maintenance and support to electric power generation experts.
Our eld personnel are 100% qualied and fully trained to operate in all environments
and on all machine types.
We have a deep understanding of alternator operation, providing the best value
service to optimise your cost of ownership.
Where we can help:
Contact us:
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