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Why Is Your Generator Not Producing Power? DIY Troubleshoot

Why Is My Generator Not Producing Power
Written by Jamie Masterson

There’s nothing worse than wasting fuel on a generator that doesn’t work. If your generator is running, but not producing any power, there are several things that could be going wrong inside. In this article, we’ll be telling you different problems that occur that will stop your generator from producing power.

Why Is My Generator Not Producing Power?

Issue 1: Defective AVR

When an AVR device malfunctions or dies, the rotor loses its current. If that happens, then the magnetic field generated by the rotor disappears. The alternator needs that magnetic field to produce power from the current.

To check if your AVR is defective, take a 9-volt battery and inject a current directly on the AVR’s feed. Use a meter to test for an output voltage. If there’s a reading, then the AVR needs to be replaced.

Issue 2: Voltage issues

A problem you’ll definitely want to avoid is misdiagnosing. The most common way this happens is when the load shorts out. When the load shorts out, the voltage from the generator will drop to zero. This is not a sign that your generator isn’t producing power.

The generator’s voltage may still be normal. To check this, disconnect the generator from the load, then check the voltage. If the reading is normal, the problem is with your load. A voltage reading of zero, however, means that your generator has failed.

Issue 3: Rotating rectifier failure

Rotating rectifier failure leads to the excitation current failing to reach the rotor. The rotor will slowly lose its magnetic field, then the alternator will stop working.

Frayed or broken tails will be the first sign that the rotating rectifier has failed. If everything looks ok, check each diode with a meter to make sure they are producing electricity. A blown or malfunctioning diode is another common cause of rotating rectifier failure.

Issue 4: Poor connections

The connections to the different parts of your generator will get dirty and loose over time. Clean any debris or dirt that is on the connections with a rag and some water. Always make sure your generator is completely dry before using it again.

Issue 5: Loss of residual magnetism

The residual magnetism left over is vital to starting the generator. If you haven’t used a generator in a long time, that magnetism may fade away. You won’t be able to start the generator.

Another cause of residual magnetism loss is running your generator without a load. A load helps create a stronger magnetic field when the generator is running, leaving more residual magnetism over. More residual magnetism will guarantee that your generator will produce power and turn on.

The best way to correct this is to run your generator at least once a month. If you have an old, unused generator, use a 12-volt battery to feed power into the generator. The magnetic field produced will be enough to get the generator started.

Issue 6: Defective breaker

Most commercial generators aren’t built to handle high voltage appliances like refrigerators or microwaves. If you hook one up to your generator, you will blow out a fuse.

The breakers are built to prevent power from overloading.  When you blow out a fuse, there’s a possibility that the breaker is defective. To check, go to the breaker box and check your fuses. Flip the switches on and off. If a breaker doesn’t turn back on then you have a defective breaker. We recommend calling a trained electrician before trying to fix these, as one mistake will lead to huge problems.

Issue 7: Brushes worn

Brushes are responsible for conducting the electrical current to the rotor. If these are worn or broken, then the current produced can’t make the trip around the circuitry.

To check if your brushes are worn, remove the cover of your alternator. The brushes are located right above the ACR of your generator. If they are frayed, you will need to replace them.

Issue 8: Blocked excitation circuit

Loose or disconnected wires will block the excitation circuit. To check if there are any loose wires, you’ll need to open the alternator cover to see the wiring to the rotor.

The first thing to check is any loose wires. When your generator’s off, reconnect any wires using a set of pliers. If all your wires are secured but you still have no power coming from the generator, check the wire connections. Loose dirt can sometimes get on the connectors, blocking the current from reaching. Simply clean the connectors until all the dirt is gone

Issue 9: Defective capacitor

Brushless generators tend to have capacitors instead of AVR units in them. They are storage units for the AC power that’s generated. Usually, they are in the same place an AVR would be.

Use your meter to check the voltage of the connections on the capacitor. Be extremely careful when doing this. A capacitor has electricity in it, so if you touch the connectors, that electricity will hit you, causing serious injury. If the voltage is 5, your alternator is fine and your capacitor is defective.

Issue 10: Broken capacitor

A bad capacitor is pretty easy to spot. Find where your capacitor is and check if it is damaged or melted. This can happen if you overload the generator.

If damaged, you will need to replace the capacitor. Luckily, capacitors are often cheap and available at any local parts store. It’s important to replace this as soon as possible. The bad capacitor can “leak” an electrical current where it’s not supposed to go. This can spell doom for your generator and the electrical system.


Q. How do I check the output of a generator?

Take an electric meter and set the reading to volts. Place the tip of the red cable into the generator’s outlet. Check the meter’s screen to see the generator’s output.

Q. What happens if a generator is underloaded?

Your motor will overwork trying to compensate for the low cylinder pressure. Soot will begin to build up in your cylinders. The soot and low pressure will kill your generator.

About the author

Jamie Masterson

With decade-long experience as a generator technician, Jamie has worked with USA’s top generator manufacturers and suppliers as an independent contractor.

The long years of service to the industry has taught Jamie the ins and outs of troubleshooting, repairing, and maintaining all kinds of generators in home, industrial and outdoor settings.

Jamie thinks this platform is a great opportunity to share his tips and tricks with you so you can make the most of such power equipment for better living.

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