How To Flash the Field on A Generator? | A Step-By-Step Guide

If you leave your generator on the shelf for a long time, it might become unable to build up voltage during startup. It mainly happens due to the loss of residual magnetism. Fortunately, there is a way to fix this problem by flashing the field on the generator.

So, how to flash the field? You can easily do it using a battery. All you need to do is “short” the “A” terminal to the “Battery +” terminal. It will soak the iron core with the residual magnetism in the correct polarity and fix the issue with your generator.

In this article, we have provided a step-by-step guide on how to flash the field on a generator and fix the mentioned issue. So, without wasting any of our valuable time, let’s get started below!

Why & When Should You Flash the Field on a Generator?

You need to flash the field on your generator if your generator doesn’t produce power even if it is running. It mainly happens if the residual magnetism of the generator is lost.

The residual magnetism is basically the leftover magnetism from the last time the generator was running. When you run the generator again, the leftover magnetism will create a very strong electric magnet to produce power. That’s how it works.

Now, if you leave the generator on the shelf for a long time, then leftover magnetism is lost. It can also happen if you run the generator for too long without connecting it to a load.

There can be more reasons why the generator becomes unable to produce power and needs to flash the field. Here are they:

If the generator is new and has never been connected to a battery,
If the generator does not have any, or enough, magnetism in the iron core.
If it charges the wrong polarity.
If the generator is low on oil.

So, you should check the oil level of your generator before flashing the field in case it isn’t providing enough power.

How Do You Flash the Field on A Generator?

There are two ways you can flash the field on a generator –

Using a battery
Using a drill

However, the drill method may not prove effective for all. Thus, we only have explained the battery method here which can successfully flash the field 90% of the time. Here are the steps to follow:

Step 1: Find the voltage regulator of the generator. In most models, is located on the bottom-left corner of the generator head.

Step 2: Unplug the two wires connected to the generator brushes. The two wires will either be red and white/black, or “F+” and “F-“.

Step 3: Now connect the black or white wire, or the F+ wire to the generator ground battery terminal or the positive pole of the battery.

Step 4: Turn on the generator breaker, start the motor, and plug in a light.

Step 5: Now, hold the red wire or F-wire by the insulated portion and connect it to the negative terminal of the battery for a second. You’ll notice an arc this time. It confirms that the circuit is complete.

Caution: Remember, you’re holding a live wire of 120 volts on the bare copper end. Handle it carefully and follow safety measures like wearing safety gloves while performing this step.

Step 6: Remove the brush wires from the voltage regulator.

Step 7: Reconnect F+ and F- or red wire and black/white wire to the regulator.

After this, your generator will be able to build voltage and will provide you with the power you need. If the generator fails to build voltage, you may need to repeat this process several times.

NOTE: Some generators may require a higher DC voltage. In that case, you need to limit the resistor in series with the battery leads.

Conclusion

Generators lose magnetism over time, which might affect their ability to produce power. Field flashing can be an effective solution in this case. A step-by-step process to flash the field on a generator is explained above and we hope you can easily fix the issue with your generator by following this guide. If you need any further assistance regarding this topic, feel free to ask in our comment section below. Always remember safety precautions when handling live wires. Thanks for reading!