Why Is My Generator Not Producing Power? Reasons And How To Fix Them

Generators have complex control circuits, and any fault can interfere with the power supply. Nonetheless, the loss of residual magnetism is the major issue that causes a portable generator not to produce power. Blocked or wiring errors in the excitation circuit can also interfere with the power supply. Besides, interrupted DC circuit, failure in AC exciter, and broken excitation winder prevents power output. 

A generator produces electric energy by converting mechanical energy. The power produced is used in the external circuit for agricultural, industrial, science and technology, and national defence purposes. Electrical conductors are moved through a magnetic field to produce electricity. If the magnetic field is not created, then there will be no power produced. Therefore, you will have to find a solution to get your device back and working. Here you will learn why a generator is not producing power and how to fix the same. Keep reading!

Reasons Why A Generator Is Not Producing Power

Too Weak Or Lost Residual Magnetism

Residual magnetism is the amount of magnetism left-over after shutting down the generator. This can be lost, resulting in challenges of the generator not producing power. The lost residual magnetism can occur naturally when the device is not used for too long or if you connect the load when the generator is shut off.  Note that long distance vibration can also make a new generator not produce power. 

It would help if you always connected the load when the generator is running to create a strong magnetic field. Remember to disconnect the load by turning off the breaker or the switch before shutting down the computer. Shutting off the generator before disconnecting the load can demagnetize or drain the electromagnet. 

Blocked Excitation Circuit

A generator cannot produce power when there is no excitation current in the excitation winding. This can be due to bad electrical contact in the circuit, or there could be a loose wiring head on each electrical component. A broken lead wire can also interrupt the circuit, causing the device not to produce power. 

Wiring Error In The Excitation Circuit

If there is a wiring error in the circuit, the excitation winding polarity is reversed.  When such happens, the generator will not produce power.  This is because remanence will disappear as residual magnetism counteracts the magnetic field produced by the field winding current.  Besides, the core remanence will disappear if you test the automatic voltage regulator (AVR) or measure the DC resistance without being attentive to polarity. 

Interrupted DC Circuit On Rotary Rectifier Side

When the DC circuit on the rotary rectifier side is interrupted, the electricity will not be generated. This is because the excitation current cannot be channelled to the excitation winding after the rotary rectifier rectifies the AC exciter. 

Faulty AC Exciter 

When the AC exciter is faulty, the synchronous generator excitation winding will not have an excitation current. Therefore, the device will not produce power when powered on. Similarly, if excitation winding is grounded or broken, there will be minimal or no excitation current. The generator will, therefore, not produce power.

How To Fix A Generator That Is Not Powering On

To fix the generator, you have to understand what is causing it not to power on. Here are some of the methods that can help you get your device up and running:

Magnetizing Method

Here you use dry or extra batteries on self-excited generators to supply power to the leading-out terminal of the excitation winding. Connect the positive pole to the positive pole and the negative to the excitation winding’s negative pole for magnetization. If your device has a magnetizing circuit in the control panel, turn the toggle switch to the magnetizing position, and the AC exciter will be magnetized. Once the generator has been magnetized, it will continue to produce power unless the issue was not due to weak residual magnetism. 

Connect The Broken Line On Excitation Winding

A broken line on the excitation winding can cause the generator not to produce power. Connecting it, therefore, will rectify the situation. But, first, use the multi-meter ohm block to help locate the broken line. However, if the issue is due to poor contact, use the fine sand cloth to polish the surface oxide surface, and a loose bolt-nut connection will be firm.

Restore Ground Fault Of The Excitation Winding

Check the ground insulation using a 500V ohmmeter. If there is a ground point, restore it, and the generator should produce power as usual. 

Correct Wiring Error In The Excitation Circuit

If there is a wiring error in your generator’s circuit, the device will not produce power. Search to check if proper wiring was done, and if not, wire properly for the generator to work well. 

Is It Okay To Run A Generator Without A Load On It? 

A generator should not be run without a load unless you are doing the initial diagnostic check. Nonetheless, running the device without a load should be done at most for 15 minutes. If you run it for a longer time, your generator can get seriously damaged and might have issues of not producing power. 

Consequences Of Running The Generator At No Or Low Load 

Increased Exhaust Emission

When you run a generator at a low load, the engine will be cooler than when it is higher. Efficient combustion will, therefore,  not be created due to low temperature. As a result, the diesel fuel used to power the generator will not be completely burned, increasing exhaust emission. You will notice white smoke coming, which is bad for the environment and can cause health issues when inhaled. 

Increased Soot And Clog Of Remaining Fuel In The Engine

Low engine temperature, which results when the generator runs in low or no load, increases the soot and cause the clog of the remaining fuel in the engine. The clogs could concentrate on critical areas such as rings and seals, decreasing the generator’s efficiency. The clogs will remain there until the situation is corrected. When you notice the issue, you need to run the device at near or at maximum load.  When the generator is running at maximum efficiency, the engine temperature increases burning the extra soot. 

Low Lubrication Which Causes Engine Wear

When contaminants such as soot accumulate in the generator’s system, they can end up mixing with the engine’s oil. As a result, the oil will be burnt off, causing low lubrication of the engine. This causes engine wear that, in turn, leads to poor operation of your device. If you notice a bluish smoke apart from the white one, it indicates that the oil is getting burnt, and the issue should be addressed. If the issue is not solved, the fuel injectors can damage, and black smoke will start coming out. This means there is no lubrication. 

What Happens If You Overload A Generator?

Overloading a generator is a serious issue that decreases the device efficiency and is not safe for your home. The generator can fail as overloading causes wear and tear. Therefore, it is important to know the signs of generator overloading to maintain your device’s integrity. Mostly, overload can be due to so many devices connected to the generator that makes the machine exceed its ideal wattage. Some devices have circuit breakers that help protect the generator against overload. 

Signs Of Generator Overload


This is a sure sign that your generator is overloaded. You will notice that the device runs its fans excessively to reduce the heat while making loud noises. Also, it will be giving out excess heat as it tries to cool itself off. Blockages and insulation issues can cause your generator to overheat, but it is good to check if overloaded before ruling that out. 

Note that overheating can cause the device to explode, especially if it is running on gasoline. Gasoline is highly flammable, and if the device overheats near the tank, the generator can catch fire. 

Exhaust Soot 

The appearance of soot in the generator’s exhaust is also a sure sign that your device is overloaded. Note that carbon particles can make exhaust dark, which is normal, but soot left-over is abnormal. Soot in the exhaust can also be a sign of bad filtering and clogging, but overloading is mostly the defect. 

Reduced Power

If the power output reduces, then your generator might be overloaded. In such a case, your generator will be straining yet generating minimum electricity. Its efficiency may reduce by half, affecting the performance of your device. 

Final Word

Your generator might not produce power due to too weak or lost residual magnetism, blocked excitation circuit, wiring error in excitation circuit, interrupted DC circuit on rotary rectifier side, or faulty AC exciter. The magnetizing method, connecting the broken lines, correcting the wiring error in the excitation circuit, or restoring grounded excitation winding can help fix the issues. Note that the generator should not be run on low or no low as it affects its power output. Besides, it can cause overheating that poses safety risks. 

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