V S UF OE UF
R121
R1 R2 U N F1 F2
R121
AVRs
Installation and maintenance
Electric Power Generation Installation and maintenance 5657 en - 2018.01 / a
R121
AVRs
This manual concerns the alternator AVR which you have just purchased.
We wish to draw your attention to the contents of this maintenance manual.
SAFETY MEASURES
Before using your machine for the first time,
it is important to read the whole of this
installation and maintenance manual. All servicing or repair operations
performed on the AVR should be
All necessary operations and interventions undertaken by personnel trained in the
on this machine must be performed by a commissioning, servicing and main-
qualified technician. tenance of electrical and mechanical
components.
Our technical support service will be pleased
to provide any additional information you
may require.
The various operations described in this When the generator is driven at a
manual are accompanied by recom- frequency below 28 Hz for more than 30
mendations or symbols to alert the user to seconds with an analogue AVR, its AC
potential risks of accidents. It is vital that power supply must be disconnected.
you understand and take notice of the
following warning symbols.
WARNING
WARNING This AVR can be incorporated in a EC-
marked machine.
Warning symbol for an operation capable This manual is to be given to the end
of damaging or destroying the machine user.
or surrounding equipment.
© - 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
Warning symbol for general danger to this document may therefore be changed
personnel. without notice.
This document may not be reproduced in
any form without prior authorisation.
All brands and models have been registered
Warning symbol for electrical danger to and patents applied for.
personnel.
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R121
AVRs
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....................................................................................................................................7
5.2 - UF ................................................................................................................................7
5.3 - S ...................................................................................................................................7
6 - AVR CONTROLS................................................................................................................. 7
7 - TROUBLESHOOTING CHART...........................................................................................8
8 - MULTIMETER CHECKS.....................................................................................................9
9 - STATIC TEST PROCEDURE............................................................................................10
10 - DIMENSIONS.................................................................................................................. 11
11 - SPARE PARTS................................................................................................................ 12
11.1 - Designation............................................................................................................... 12
11.2 - Technical support service..........................................................................................12
Disposal and recycling instructions
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R121
AVRs
1 - GENERAL DESCRIPTION 2 - OPERATION OF THE AVR
The R121 automatic voltage regulator The AVR is powered by the terminals of the
(AVR) is a compact, high-performance AC generator, with 110 V-220 VAC rms at
encapsulated unit. It incorporates the latest 50 Hz or 60 Hz. The sensing voltage, which
technology and efficient components to is the regulated voltage, is also based on the
achieve a high degree of miniaturisation input power. The AVR forms an important
when used with 3-phase and 1-phase AC part of the closed loop system comprising
brushless generators within its input and the generator field, generator armature and
output limits. The unit offers excellent the AVR.
reliability.
The AVR first builds up the generator voltage
The AVR provides DC excitation to the from its residual levels to the rated voltage
exciter field of a brushless generator to keep value. When the generator is loaded, the
the voltage within the approximate operating sensed voltage decreases and generates
limits from NO-LOAD to FULL LOAD. an error voltage, which is required in order
for the closed loop system to work.
The typical recovery time in the event of
sudden loading is around 0.5 sec. to recover The AVR contains a high gain amplifier.
97.5% of the rated voltage. Transient Depending upon the value of the amplifier
performance such as voltage dip and voltage (either high or low) the ramp
recovery time is mainly determined by the intersects the amplified voltage at a point,
generator and exciter design parameters. which is either early or late in the half-cycle.
Optimum AVR performance can be obtained At this intersection point a starting pulse is
by keeping full-load excitation to around produced to trigger the power device.
60 VDC.
When the power device is triggered early in
The generator uses a true average sensing the half-cycle, more voltage is fed to the field
circuit, dV/dt snubber and special filter and when triggered late in the half-cycle,
circuits to manage NON-LINEAR loads less voltage is transmitted to the field.
such as battery chargers, DC motors, etc.
In order to reduce the generator voltage at
Voltage regulation is only guaranteed for low speed, a signal inversely proportional to
linear loads. Severely distorting NON- the speed is generated as an extra input.
LINEAR loads can cause regulation
problems.
Each AVR is tested prior to dispatch as part
of a quality plan, for standard voltage and
frequency.
A soft-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.
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Electric Power Generation Installation and maintenance 5657 en - 2018.01 / a
R121
AVRs
3 - TECHNICAL SPECIFICATION 17) Potentiometer sealing: except for the
1) Sensing input and Input power V-trim potentiometer, all potentiometers are
- Voltage: 90 V to 277 VAC ±10%, 50/60 Hz sealed.
2) Output power 18) Frequency roll-off indicator: LED
- Voltage: provided (UF).
• 95 VDC at 220 VAC Input 19) Overexcitation indicator: LED provided
• 50 VDC at 90 VAC (OE).
- Current:
• 6 A DC 20) Protection on the devices: suitable R-C
• 8 A for 30 sec. (when allowed by the field snubber to be provided for the device used
resistance) to protect against voltage surges.
3) Operating temperature: -20ºC to +70ºC. 21) Dimensions:
- Overall: 105 x 96 x 38 (in mm)
4) Storage temperature: -40ºC to +80ºC. - Mounting: 83 (in mm)
5) Voltage setting: min ± 10% of rated - Mounting hole dia: 6 (in mm)
voltage. 22) Weight: 185 g.
6) External potentiometer voltage setting:
min ± 15% of rated voltage with 2 K
potentiometer.
7) Stability setting: can be adjusted to obtain
a correct transient response in steady state.
8) Under frequency roll-off setting: available
below 48.5 Hz for 50 Hz and below 58.5 Hz
for 60 Hz.
9) Voltage build-up: 2 Volts (U-N).
10) Voltage regulation: ± 1% at the AVR
terminals.
11) Thermal drift: ± 1% for 30º C change in
temperature.
12) Response time: less than 50 ms.
13) Closed loop response: typically 0.5 sec
to recover 97.5% of the defined voltage for a
field forcing ratio of 1:2.
14) Sensing loss protection: the voltage
should disappear when the sensing circuit is
open.
15) Overexcitation protection: 95 VDC.
16) Protection fuse: 6.3 A, 240 VAC.
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Electric Power Generation Installation and maintenance 5657 en - 2018.01 / a
R121
AVRs
4 - MAIN FUNCTION OF THE AVR
The AVR is powered by the terminals of the AC generator with 110 VAC-220 VAC at 50/60 Hz.
The regulated sensing voltage is based on the AVR input power.
MAIN FIELD STATOR: 12 wires (T1 to T12 identification)
T1 T7 T2 T8 T3 T9
Armature
Varistor
black red
- + T4 T10 T5 T11 T6 T12
Exciter field
Voltage reference
Fuse
Slow blow
250 V 6.3 Amps
Under speed
F2
Over excitation
limit
UF OE
F1
50 Hz/60 Hz
N
section
U
Under speed
UF
R2
R121
S
Stability
R1
V
2K POTENTIOMETER
Voltage setting OR WIRE LINK
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R121
AVRs
The AVR builds up the generator voltage External voltage setting up to ±15% of rated
from its residual voltage to rated voltage. voltage with 2K potentiometer on terminals
When the generator is loaded, the sensed R1 and R2.
voltage decreases and generates an error
signal, which is required in order for the 5.2 - UF - Under frequency knee
closed loop system to work. point setting
Depending upon the value of the amplified This function is provided to protect the AC
voltage, the ramp intersects the amplified generator from sustained low speed
voltage at a point which is early or late in the operation through a potentiometer. The
half-cycle. AVR will reduce the voltage in proportion
At this intersection point, a starting pulse is with the speed below the defined value.
produced to trigger the power device. The procedure for setting the UF
potentiometer is as follows:
First select 50 Hz/60 Hz mode on the AVR.
Run the generator at 48.5 Hz for a 50 Hz
system (or 58.5 Hz for a 60 Hz system). Turn
the UF potentiometer until the UF LED
Only qualified personnel should replace/ blinks. The potentiometer position at which
work on the AVR. the UF LED blinks is the correct UF
Do not increase the voltage beyond the potentiometer setting.
rated voltage. The factory default setting is 48.5 Hz.
5 - AVR SETTINGS 5.3 - S
5.1 - V - Voltage This function is provided to stop voltage
This function is provided for setting the hunting by means of a potentiometer. Turn
voltage up to ±10% of rated voltage by clockwise to increase stability (to stop
means of a single-turn potentiometer. Turn oscillation). Turning too far clockwise will
the potentiometer clockwise to increase the result in a sluggish response and possibly
voltage and vice versa, once the rated also oscillations.
speed has been reached. The factory default setting is slightly
higher than critical damping.
6 - AVR CONTROLS
No. Control Function Direction
Sets the generator output
1 V Turn clockwise to increase output voltage
voltage
2 S Stops voltage hunting Turn clockwise to increase stability
Sets the Under frequency
3 UF Turn anticlockwise to reduce the knee point
knee point
50 Hz/60 Hz Selects 50 Hz mode or 60 Hz
4 60 Hz operation is selected when kept open
selection mode of operation
Caution: Whenever the R121 AVR is used with low voltage 110 VAC generator (parallel
connection) for the first time, the AVR should be started with Voltage pot V in the minimum
position (fully anticlockwise). The R121 AVR can generate high voltage because the
voltage range is from 110 VAC to 270 VAC.
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Electric Power Generation Installation and maintenance 5657 en - 2018.01 / a
R121
AVRs
7 - TROUBLESHOOTING CHART
Symptom Cause Action
No voltage Fuse blown Check and replace
build-up Low residual voltage across U If the generator’s residual voltage at rated speed
and N terminals 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 or
equivalent) across the field with the diode cathode
to F1 and the anode to F2 during field flashing will
help restore the residual voltage.
WARNING:
Remove the diode (BY-127) after field flashing.
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 Check and replace
failed
Voltmeter on the front Check and correct
defective
AVR defective Replace after performing a static test
(repeated fuse blowing)
Earthed exciter field Check and correct
High voltage Incorrect setting Check and correct
build-up AVR defective Perform a static test and replace if necessary
Low voltage Low prime mover speed Check and correct
build-up Incorrect setting Check and correct
AVR defective Replace the AVR
Voltage oscillation Incorrect stability Turn clockwise until hunting stops
potentiometer sealing
Prime mover speed hunting Check and adjust the controller
Load hunting, fluctuates Check and correct
rapidly
High percentage of non-linear Check and reduce the non-linear load
loads
High reactance in generator Consult the generator manufacturer
(during non-linear loading)
Incorrect The exciter field’s requirement Wrong selection or very low P.F. load.
regulation is too high Check and correct.
Prime mover speed drops too Adjust the controller and reduce the active load
much when on load (kW load)
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Electric Power Generation Installation and maintenance 5657 en - 2018.01 / a
R121
AVRs
8 - MULTIMETER CHECKS
Equipment: Digital multimeter
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 V, 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 greater than 200 Kohms.
ZERO indicates a power device failure in
both cases, No further tests (static test or
dynamic tests) are allowed, and it will lead to
the fuse blowing.
The resistance between U and N (both
sides) should be greater than 200 Kohms.
ZERO indicates a power device failure in
both cases, No further tests (static test or
dynamic tests) are allowed, and it will lead to
the fuse blowing.
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Electric Power Generation Installation and maintenance 5657 en - 2018.01 / a
R121
AVRs
9 - STATIC TEST PROCEDURE
230 V 60 W
Lamp
V
F2
DC
UF OE
F1
N
250 VAC
U
50 Hz
UF
R121 R2
V
S
DC
AC
Variac
R1
V
3A
2K Potentiometer OR
WIRE LINK
This test should only be attempted after First keep the “S” potentiometer in the fully
making sure that the AVR has passed all anticlockwise position. Perform the static test
multimeter checks. Connect the AVR to the as described in steps 1, 2 and 3. The lamp will
single-phase variable voltage source as go out fairly quickly at 90 V-95 V and come on
shown in diagram 1 in this manual. again quickly when the voltage is reduced to
1. Keep “V-TRIM” in the minimum position. below 90 V.
Now keep the “S” potentiometer fully
2. Keep “UF” in the fully anticlockwise position.
clockwise, and perform the static test as
3. Increase the applied voltage. The lamp described in steps 1, 2, and 3. The lamp
should glow increasingly brightly. At a voltage should go out much more slowly and come on
of around 90 V-95 V the lamp should go out again much more slowly. At the end of this test
slowly. Increase the voltage again up to reset the potentiometer in the middle position.
240 V. The lamp should stay OFF.
6. Turn the “V” potentiometer fully clockwise.
Decrease the voltage to below 90 V. The lamp
Increase the voltage to 250 V. The “OE” LED
should glow again.
should glow and the voltmeter at F1 and F2
4. Turn the “UF” potentiometer clockwise. The should read 95 V. Increasing the voltage to
UF LED will glow. The lamp should go out 305 V will turn off the lamp.
slowly. Now turn “UF” potentiometer
7. Connect the 2K potentiometer at terminals
anticlockwise. The UF LED will go out. The
R1 and R2. Turn the external potentiometer
lamp should glow brightly again.
both fully clockwise and anticlockwise. The
5. It is difficult to prescribe a static test for lamp should turn off and on alternately.
checking the stability, as this is more easily
detected during closed loop tests. However, a If the AVR behaves as described above
healthy AVR will behave as described below. then it is in good working order.
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Electric Power Generation Installation and maintenance 5657 en - 2018.01 / a
R121
AVRs
10 - DIMENSIONS
2 x HOLES Ø 6 mm
COUNTER BORE 9 mm x
5 DEEP
1 mm
F2
OE UF
82.5 mm
83 mm
96 mm
F1
N
U
S UF
R2
R1
V
52.5 mm 52.5 mm
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Electric Power Generation Installation and maintenance 5657 en - 2018.01 / a
R121
AVRs
11 - SPARE PARTS
11.1 - Designation
Description Type Code
AVR R121 5107292
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
service.epg@leroy-somer.com or your
closest contact, whom you will find 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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Electric Power Generation Installation and maintenance 5657 en - 2018.01 / a
R121
AVRs
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 (199) 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.
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R121
AVRs
14
Service & Support
Our worldwide service network of over 80 facilities is at your service.
This local presence is our guarantee for fast and efficient repair, support and
maintenance services.
Trust your alternator maintenance and support to electric power generation experts.
Our field personnel are 100% qualified 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:
Design
•Consulting & specification
•Maintenance
contracts
Life Extension
•Reconditioning Start-up
•System upgrade
•Commissioning
•Training
Optimisation
•Monitoring Operation
•System audit •Genuine spare parts
•Repair services
Contact us:
Americas: +1 (507) 625 4011
Europe & Rest of the world: +33 238 609 908
Asia Pacific: +65 6250 8488
China: +86 591 88373036
India: +91 806 726 4867
Middle East: +971 4 811 8483 Scan the code or go to:
service.epg@leroy-somer.com www.lrsm.co/support
www.leroy-somer.com/epg
Linkedin.com/company/Leroy-Somer
Twitter.com/Leroy_Somer_en
Facebook.com/LeroySomer.Nidec.en
YouTube.com/LeroySomerOfficiel
5657 en - 2018.01 / a
