Are you facing the issue with AVR? Don’t worry I will show you the best possible way to test an AVR with Multimeter. Before we proceed further first of all we will discuss AVR.
What is AVR (Automatic Voltage Regulator)?
An Automatic Voltage Regulator or AVR is used to protect the electronic equipment from surges. The best thing is it automatically regulates the voltage provided to equipment.
AVR is Protected by absorbing the fluctuating voltage. These fluctuations mostly occur because of changes in load. The change in voltage with load can be compensated by installing the voltage control equipment near feeders, generators, and transformers. The voltage controller can be used at any point near the control components.
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For AC and DC methods of voltage regulation are different.
In DC voltage is compensated using compound generators and feeder booster, while in the case of AC the voltage is regulated using a shunt condenser, induction regulators, and booster transformer.
What Are the Functions of an Automatic Voltage Regulator?
The functions of AVR are given below
- Under fault it will increase excitation so that maximum power should be provided after clearing the fault.
- Automatic voltage controller controls the overvoltage when the load is suddenly cut from the system.
- When the alternators are working in parallel, it will separate the reactive load.
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What causes AVR failure?
The generator AVR failure symptoms are
- Sudden power changes
When the load on the generator suddenly changes there is a high possibility that AVR will experience shock. The AVR will not stabilize the voltage when the power drawn increases suddenly.
- Overload
Also, when the generator will be overloaded its frequency will decrease, so there would be a voltage drop. To compensate for this drop voltage regulator will try to provide a constant voltage. So it can be damaged.
- Short circuit
When the short circuit will happen in case of fault. If the relays do not operate the breaker it will damage both the generator and voltage regulator.
- Uneven generator engine speed
when the generator speed will suddenly increase voltage produced will also increase. The suddenly increased voltage will damage AVR.
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How to test an AVR with multimeter?
To test the generator AVR with a multimeter follow these steps.
- Rotate the Multimeter Knob to AC voltage.
- Connect the red probe to the L pin and the
- black probe to the N pin.
- To check the output. Rotate the Multimeter knob to DC.
- Connect the Black probe to the negative pin and Red Probe to the positive pin.
- For 220V AC input, the output voltage must be around 90-100v DC.
- If you don’t have a multimeter you can connect the test lamp at the output to check if AVR working or not.
We have tried to cover every aspect of How to Test an AVR with a Multimeter? and will look for more and try to add those in the next update. If you still have any confusion while checking the Automatic voltage regulator. Let us know in the comment below.
Frequently Asked Questions (FAQs)
How do you check the AVR on a generator?
To check the AVR on the generator
- Rotate the Multimeter knob to AC and connect the meter probe to input pins.
- Now, to check the output Rotate the Multimeter Knob to DC and connect the knob to output pins.
What causes AVR failure?
The causes of AVR failure are
- Sudden Power change
- Overload
- Short Circuit
- Uneven generator speed
How do I know if my AVR is good?
To check the AVR
- Connect it to input supply and check reading with Multimeter.
- At out connect the load and rotate the multimeter knob to DC and check voltage.
- If the load is working properly and the meter is giving a reading it means AVR is good.
Thank you very much for your explanation.
You make it seems simple. But please you we reed the input ac voltage and the output dc voltage while the generator in running?
Can we connect a 220 ac voltage to the input and read the output while we have disconnected the avr from the generator?
For testing you need to disconnect it from generator
Hi I have a question for you I have a genarator Black Max 7000 run 8750 surge the genarator runs good but don’t give power I tested with my digital multimeter and I found this the fréquence is good but I have around 1.50 Volts DC When I tested the power on the (new) brush I founded around 12 volts DC the AVR was replaced with another one builded in 2022 ( more recently than the genarator) and the model number on it is 310227076 first I would like to know if this part is compatible with this genarator (8750 Watts surge) and I would like to know before to buy a new one how to test it have I to run the genarator let it connected or have I to disconnect all of wire before testing thank you
It’s difficult to determine if the AVR part you mentioned is compatible with your Black Max 7000 generator without more specific information about the make and model of the generator. However, if the part was specifically purchased as a replacement for the AVR in your generator, it is likely compatible. Also, To test the AVR, you should disconnect all wires from the generator and remove the AVR from the generator unit.
AVR , brush problems
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