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Imagine you are on a road trip with your family, enjoying the scenery and the freedom of your RV. You have everything you need: a comfortable bed, a fridge full of food, a TV to watch your favorite shows, and a generator to power them all. Life is good.
But then, something goes wrong. You notice that your TV is flickering, your fridge is making strange noises, and your lights are dimming. You check your generator and see that it is running, but the voltage meter shows a low reading. What is happening? How can you fix it?
This is a common problem that many RV owners face: low voltage output from their onan generator. Low voltage output can damage your appliances and devices, and reduce the performance and lifespan of your generator.
In this blog post, we will explain what causes low voltage output from an Onan generator, and how to fix it. Let’s get started!
What Causes Low Voltage Output from an Onan Generator?
Low voltage output from an onan generator is a common problem that can affect the performance and safety of your appliances and devices. There are several possible causes and solutions for this issue, which I will explain in detail below:
1. Load is More Than The Generator Capacity
One of the main causes of low voltage output from an onan generator is overloading the generator with more power demand than it can handle.
This can cause the generator to slow down or lose voltage, resulting in flickering or dimming lights, appliances not working properly or shutting off, low battery charge, error codes on the generator display, and unusual noises from the generator.
How to Fix This
To fix this, you need to reduce the load on the generator by unplugging some of the appliances or devices or using a larger generator that can meet your power needs. You can also use a load meter to monitor the power consumption of your generator and avoid overloading it.
2. The Circuit Breaker is Faulty
Another common cause of low voltage output from an onan generator is a faulty circuit breaker.
A circuit breaker is a device that protects the generator and the appliances from damage due to high voltage or current.
If the circuit breaker is tripped or broken, it may lower the power supply unnecessarily, causing low voltage output.
How to Fix This
To fix this, you need to check the location of the circuit breaker and make sure it is in the ON position.
You also need to measure the resistance of the lead wire connections and the electrical panel using a multimeter.
If the resistance is normal, the circuit breaker is working fine. If the resistance is overloaded or infinity, the circuit breaker is faulty and needs to be replaced.
3. Loose Or Corroded Connections
A third common cause of low voltage output from an onan generator is loose or corroded connections.
The connections between the generator and the appliances, as well as the internal connections of the generator, need to be tight and clean to ensure a smooth and stable power flow.
If the connections are loose or corroded, they can create resistance and voltage drop in the circuit, resulting in low voltage output.
How to Fix This
To fix this, you need to inspect the wires and connections of the generator and the appliances, and tighten or replace them if they are loose or corroded. You can also use a wire brush or a contact cleaner to remove any dirt or rust from the connections.
4. A Faulty Automatic Voltage Regulator (AVR)
A fourth common cause of low voltage output from an onan generator is a faulty automatic voltage regulator (AVR).
The AVR is a component that regulates the voltage output of the generator by adjusting the current flow to the rotor.
If the AVR is damaged or malfunctioning, it can cause the voltage output to be too high or too low, resulting in low voltage output.
How to Fix This
To fix this, you need to test the AVR using a voltmeter and following these steps:
- Disconnect the negative battery cable from the battery.
- Locate the AVR on the generator. It is usually a small metal box with wires attached to it.
- Disconnect the wires from the AVR and label them for reconnection.
- Set the voltmeter to DC voltage mode and connect the red probe to the positive terminal of the AVR and the black probe to the negative terminal.
- Start the generator and observe the voltmeter reading. It should be between 13.5 and 14.5 volts. If it is lower or higher, the AVR is faulty and needs to be replaced.
- Stop the generator and reconnect the wires and the battery cable.
5. Faulty Capacitor
A fifth common cause of low voltage output from an onan generator is a faulty capacitor. However, not all Onan generators have capacity. Some do while others have AVR. If yours is not with capacity, then it’s an AVR Generator.
The capacitor is a component that stores and releases electric charge and helps to induce voltage into the rotor and regulate voltage output.
If the capacitor is damaged or worn out, it can cause the voltage output to be low or unstable, resulting in low voltage output.
How to Fix This
To fix this, you need to test the capacitor using a multimeter and following these steps:
- Disconnect the negative battery cable from the battery.
- Locate the capacitor on the generator. It is usually a cylindrical or rectangular device with two terminals.
- Disconnect the wires from the capacitor and label them for reconnection.
- Set the multimeter to capacitance mode and connect the probes to the terminals of the capacitor.
- Observe the multimeter reading. It should match the capacitance value printed on the capacitor. If it is lower or higher, the capacitor is faulty and needs to be replaced.
- Reconnect the wires and the battery cable.
6. Ground Fault in Field Winding
A sixth common cause of low voltage output from an onan generator is a ground fault in the field winding.
The field winding is a coil of wire that creates a magnetic field when current flows through it and helps to generate voltage in the stator.
If the field winding is short-circuited or grounded, it can cause the voltage output to be low or zero, resulting in low voltage output.
How to Fix This
To fix this, you need to test the field winding using a multimeter and following these steps:
- Disconnect the negative battery cable from the battery.
- Locate the field winding on the generator. It is usually a set of wires wrapped around the rotor.
- Disconnect the wires from the field winding and label them for reconnection.
- Set the multimeter to resistance mode and connect the probes to the wires of the field winding.
- Observe the multimeter reading. It should be within the range specified by the generator manufacturer. If it is lower or higher, the field winding is faulty and needs to be replaced.
- Reconnect the wires and the battery cable.
7. Mechanical Malfunction
A seventh common cause of low voltage output from an onan generator is a mechanical malfunction.
The generator may have some mechanical problems that prevent it from running at full speed and power, such as dirty or clogged filters, turbo, or fuel tank, low fuel or oil level, worn out or damaged parts, etc.
These problems can cause the generator to produce low voltage output, resulting in low voltage output.
How to Fix This
To fix this, you need to check and clean the filters, turbo, and fuel tank, refill the fuel or oil, and replace any worn-out or damaged parts. You may also need to seek professional help if the problem is beyond your ability to fix.
8. Alternator Malfunction
An eighth common cause of low voltage output from an onan generator is an alternator malfunction.
The alternator is a device that converts mechanical energy into electrical energy and helps to generate voltage in the stator.
If the alternator is damaged or malfunctioning, it can cause the voltage output to be low or unstable, resulting in low voltage output.
How to Fix This
To fix this, you need to test the alternator using a multimeter and following these steps:
- Disconnect the negative battery cable from the battery.
- Locate the alternator on the generator. It is usually a large metal device with wires attached to it.
- Disconnect the wires from the alternator and label them for reconnection.
- Set the multimeter to AC voltage mode and connect the probes to the output terminals of the alternator.
- Start the generator and observe the multimeter reading. It should be within the range specified by the generator manufacturer. If it is lower or higher, the alternator is faulty and needs to be replaced.
- Stop the generator and reconnect the wires and the battery cable.
9. Stator Problem
A ninth common cause of low voltage output from an onan generator is a problem with the stator.
The stator is a set of coils of wire that surrounds the rotor and helps to generate voltage when the rotor spins.
If the stator is damaged or short-circuited, it can cause the voltage output to be low or zero, resulting in low voltage output.
How to Fix This
To fix this, you need to test the stator using a multimeter and following these steps:
- Disconnect the negative battery cable from the battery.
- Locate the stator on the generator. It is usually a ring of wires inside the generator casing.
- Disconnect the wires from the stator and label them for reconnection.
- Set the multimeter to resistance mode and connect the probes to the wires of the stator.
- Observe the multimeter reading. It should be within the range specified by the generator manufacturer. If it is lower or higher, the stator is faulty and needs to be replaced.
- Reconnect the wires and the battery cable.
10. Generator Speed
Lastly, the speed of an onan generator affects the voltage output and the frequency of the power.
The speed is controlled by the governor, which adjusts the throttle according to the load demand.
The speed should be within the range specified by the generator manufacturer and can be measured by a tachometer or a frequency meter.
If the speed is too high or too low, it can affect voltage output, as well as damage the generator or the appliances.
How to Fix This
To fix this, you need to locate the voltage adjustment screw on the generator and turn it clockwise or counterclockwise until the desired voltage output is achieved.
You can also use a voltmeter to measure the voltage output at the output terminals of the generator.
General Guide on How to Fix Onan Generator Low Voltage Output
Depending on the cause of the low voltage output, here is the general guide to fix it. Here are some general steps you can follow:
Step 1: Turn off your generator and disconnect all the appliances and devices from it. This will prevent any further damage or injury from the low voltage output.
Step 2: Check the voltage output from your generator using a voltmeter. You can do this by connecting the voltmeter to the output terminals of your generator and turning it on.
If the voltage reading is lower than the normal range, you have a low voltage output problem.
Step 3: Identify the cause of the low voltage output using the methods described above. Once you find the cause, you can proceed to fix it using the appropriate solution.
Step 4: After fixing the problem, check the voltage output again using the voltmeter. If the voltage reading is within the normal range, you have successfully fixed the low voltage output problem.
You can reconnect your appliances and devices to your generator, and enjoy the power supply. If the voltage reading is still low, you may have another problem, or you may need to adjust the voltage regulator on your generator.
If you are not confident or experienced in doing this, you should contact an authorized service center or a qualified technician for assistance.
RECOMMENDED READ:- How to Jumpstart an Onan RV Generator: Expert Guide
Final Words
Low voltage output from an onan generator can be a frustrating and potentially dangerous problem. However, with some basic knowledge and tools, you can fix it yourself, or at least identify the cause and seek professional help. We hope this blog post has helped you understand what causes low-voltage output from an Onan generator, and how to fix it. If you have any questions or comments, please feel free to leave them below.
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