How to test a generator capacitor?
Step Three: If your ohmmeter reads less than 20 infinite ohms then
This is a guide on how to test the capacitor of a generator. The testing process is easy and can be done without any special tools.
- Determine the voltage rating of the generator capacitor, which can either be 220 VAC or 240 VAC depending on where you live. For example purposes, we will call it 220 volts for this article.
- Use an ohmmeter and set it to read resistance values between 20 and 100 ohms. Place one lead of the ohmmeter on one end of the capacitor’s wiring harness; place the other lead on the opposite end of that same wiring harness (Fig 1).

If you have a reading of 20 infinite ohms or less, the capacitor is bad. If the resistor reads between 21 and 99 ohms, it is safe to assume that your generator capacitor is fine. However, there are no hard and fast rules for this test because each generator may be slightly different from one others.
Therefore, if you receive an infinite resistance value when checking the capacitor’s voltage rating then it would be wise to invest in a new unit.
- If your ohmmeter reads less than 20 infinite ohms then the capacitor is fine. If not, refer to an automotive manual on how to replace the part (Fig 2).
Though this process seems somewhat complicated at first glance it can easily be completed in less than 10 minutes. If you are uncertain about your ability to safely hook up the capacitor, contact a professional garage or electrician to complete the replacement/testing process for you.
Summary:
This article is an instruction on how to test generator capacitors without special tools. The testing a generator process can be completed using an ohmmeter, which measures resistance values between 20 and 100 ohms. If the ohmmeter reads between 21 and 99 ohms then it is safe to assume that the capacitor is fine; however, there are no hard and fast rules for this test because each generator may be slightly different from one another.
Therefore, if you receive an infinite resistance value when checking the generator’s voltage rating then it would be wise to invest in a new unit. If your ohmmeter reads less than 20 infinite ohms then the capacitor is fine. If not, refer to an automotive manual on how to replace the part. This article was written by an author named Joe Doe who works at Joe’s Garage.
How Does A Generator Capacitor Work?
A generator capacitor is a device that controls the voltage and current produced by a generator. Without the use of capacitors, generators would produce high frequencies and low voltages which would not be suitable for powering large appliances in houses, buildings, etc.
A capacitor’s job is to regulate the amount of electricity released by a generator during each cycle of power generation. This ensures that there are no surges or loss in voltage production when demand is at its highest (i.e., summer afternoons with all appliances running simultaneously).
First-time mechanic Joe Doe walks you through how to test your generator’s capacitor using an ohmmeter in this article. The testing process can be completed using an ohmmeter, which measures resistance values between 20 and 100 ohms. If the ohmmeter reads between 21 and 99 ohms then it is safe to assume that the capacitor is fine; however, there are no hard and fast rules for this test because each generator may be slightly different from one another.
Therefore, if you receive an infinite resistance value when checking the generator’s voltage rating then it would be wise to invest in a new unit. If your ohmmeter reads less than 20 infinite ohms then the capacitor is fine. If not, refer to an automotive manual on how to replace the part.
Joe Doe walks his readers through step-by-step instructions on how to isolate whether or not their generator’s capacitor needs replacement using just an ohmmeter (an ohmmeter measures electric resistance of a circuit). Joe Doe explains that there is no quick and easy way to test a generator capacitor with an ohmmeter, but he provides the three necessary steps to do so.
First, readers need to find out how many volts their generator can produce. Then they should determine if the ohmmeter reads infinite resistance (around 20-100 ohms) or less than 20 ohms of resistance. If it reads below 20 ohms then the generator capacitor needs replacement; otherwise it is safe to assume that your unit is fine.
It is important to understand that since each individual generator’s voltage rating may be different from another’s, there are no hard and fast rules for this test. Therefore, if you receive an infinite resistance value when checking the generator’s voltage rating then it would be wise to invest in a new unit. If your ohmmeter reads less than 20 infinite ohms then the capacitor is fine.
It is important that one understands that there is no quick and easy way to test a generator capacitor with an ohmmeter, but Joe Doe provides three necessary steps to do so: first, you need to find out how many volts your generator can produce; second, you need to determine if the ohmmeter reads infinite resistance (around 20-100 ohms) or less than 20 ohms of resistance; and third, if your reading falls below 20 ohms then the capacitor needs replacement; otherwise it is safe to assume that your unit is fine.
What is the function of capacitors in Generators
A capacitor is an electronic device that can store electric charge. The symbol for a capacitor is: . All capacitors have two conductive plates separated by an insulator. For capacitors, the unit of measurement is coulombs (C).
When one plate has a positive voltage and the other has a negative charge, they attract each other and create an electric field between them. The amount of energy stored in this electric field depends on how much surface area there is between the plates and how many charges are separated on the plates.
Capacitors always try to maintain a constant voltage and current within a circuit; however, there will always be some power lost as heat every time current changes direction through a resistor or inductor. A generator’s capacitor is often one of the first components to be replaced after a power failure.
How to Test a Generator Capacitor: Step-by-Step Instructions
A generator’s capacitor is used to maintain a constant voltage and current within a circuit; however, there will always be some power lost as heat every time current changes direction through a resistor or inductor.
The amount of energy stored in this electric field depends on how much surface area there is between the plates and how many charges are separated on the plates. It also depends on how much voltage difference exists between the two plates (the greater the voltage, the more energy).
A capacitor stores an electrical charge when one plate has a positive voltage and the other has a negative charge, they attract each other and create an electric field between them. A generator’s capacitor is often one of the first components to be replaced after a power failure.
How to Test a Generator Capacitor: The Easy Way
The function of generators is to produce electrical power, but they need a capacitor to maintain a constant voltage and current within a circuit. The amount of energy stored in this electric field depends on how much surface area there is between the plates and how many charges are separated on the plates.
It also depends on how much voltage difference exists between the two plates (the greater the voltage, the more energy). In most cases, if your generator does not have enough charge for its size or if it is taking too long to build up charge, you will need a new unit.
However, if your generator has an infinite resistance value when checking its voltage rating then it would be wise to invest in a new unit. A generator’s capacitor is often one of the first components to be replaced after a power failure.
Therefore, if you receive an infinite resistance value when checking the generator’s voltage rating then it would be wise to invest in a new unit. If your ohmmeter reads less than 20 infinite ohms then the capacitor is fine.
A capacitor stores an electrical charge when one plate has a positive voltage and the other has a negative charge, they attract each other and create an electric field between them.
The amount of energy stored in this electric field depends on how much surface area there is between the plates and how many charges are separated on the plates. It also depends on how much voltage difference exists between the two plates (the greater the voltage, the more energy).
In most cases, if your generator does not have enough charge for its size or if it is taking too long to build up charge, you will need a new unit. However, if your generator has an infinite resistance value when checking its voltage rating then it would be wise to invest in a new unit.
A capacitor stores an electrical charge when one plate has a positive voltage and the other has a negative charge; they attract each other and create an electric field between them.
The amount of energy stored in this electric field depends on how much surface area there is between the plates and how many charges are separated on the plates. It also depends on how much voltage difference exists between two plates (the greater the voltage, the more energy). If your ohmmeter reads less than 20 infinite ohms then the capacitor is fine.