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A multimeter is a hand-held diagnostic tool that’s superior in taking various readings. It can be used to measure voltage, ohms, and amperes. Advanced multimeters can even take more readings like frequency, capacitance, etc. but those come at a price. That’s why multimeters are much better than voltmeters for performing tests on generators.
We recommend a digital multimeter, as it’s much more capable and more accurate than an analog multimeter. In this guide, we will be diving deeper into how to test a generator with a multimeter. Testing a generator is an easy procedure, even for a layperson. All you need is to understand how your generator works and take some safety precautions.
In addition to having a digital multimeter, make sure you have the following tools when carrying out generator tests
Safety Tip: Ensure that you don’t touch the voltage regulator or any other wires while performing your test. You could get an electric shock if not careful. Use gloves.
Portable generators are very useful because they are flexible and can be used for different situations such as camping, powering different tools in a remote location, or acting as an emergency backup power sources. Car generators are fitted into a car to charge the battery and provide power. You must carry your multimeter to test your portable and car generators anywhere you go with it. Follow this process to do it safely and accurately.
Safety Tip: Always put on sandals and stand on a rubber mat when using a multimeter to test your generator. Alternatively, you can wear shoes with a non-conductive sole.
The generator’s output readings are higher because generators produce slightly more electricity than labeled to allow for resistance in the cables. For a 12V car fitted generator. The reading should be about 12.6 volts with the engine off and that this value should be half for a 6-volt generator
If your 12-volt generator produces a voltage below 11 volts, there is a procedure for troubleshooting and understanding the problem. If the generator has an automatic voltage regulator or AVR, you need to test it, as it could be the culprit. Here are the steps on how to go about it
Locate the automatic voltage regulator on the generator and disconnect it
Do this by removing its two leads. Also, disconnect the red &black leads going from the AVR to the brush set.
Using electrical tape covers both the red and black leads to prevent them from touching or getting into contact with the housing.
Get a 12-Volt DC power source such as your car’s battery and some alligator clips.
Connect the clips to the generator’s brush set. Note: you are hooking them to where you removed the leads.
Connect the positive line you just attached to the brush set to your battery. Do not connect the negative line yet.
Turn on the generator, and after it has run for 10 seconds, connect the negative line you that you attached to the brush set to your car’s battery.
Place your multimeter leads on the generator leads that you disconnected the automatic voltage regulator from to test it.
The reading on your multimeter should be at least 60V. If this method didn’t work, the chances are that your automatic voltage regulator is the problem. Alternatively, the generator may be unable to produce electricity because of other failing parts. Take it for repairs and servicing.
Just a random guy who likes to build things. Providing tool knowledge, appliance/device testing tips, and DIY project info in an easy-to read & non-intimidating style.