Marine Motor & Generator Repair Tips

What It Means to “Flash” a Boat Generator

“Flashing” is a term that relates to restoring the magnetism to your boat’s generator.

But when would you need to do that? And what causes a generator to lose its magnetism?

Let’s start with the basics.

Generators use magnetism to function. They rotate coils of wires through magnetic fields (created by electric or permanent magnets), and this gets electrons in the wires moving, creating an electric current.

(It’s important to note, here, that residual magnetism can build up in the generator’s exciter field. This allows the generator to build up voltage during start-up.)

But generators can also lose magnetism. This can cause them to abruptly stop working or fail to generate power at start-up. They might lose magnetism over time, due to prolonged shelf life, or it can happen through improper operation of the generator.

(You can find some troubleshooting tips to help you identify and prevent the latter occurrence here.)

If you lose magnetism, don’t worry: You can restore it. This is done by “flashing,” or more thoroughly, “flashing the exciter field.” Sometimes, this is also referred to as “reflashing” or “exciting.” Another colloquial phrase is “blazing the field.”

(Remember how the residual magnetism was built up in the exciter field? This is what you’re going to be restoring.)

Generally, magnetism is restored via battery charge. But if the battery is connected improperly, or if you choose the wrong voltage for your generator type, you can do permanent damage—and potentially even hurt yourself. We recommend letting experts flash your generator for efficacy and safety, and we welcome you to reach out to us anytime for quick, friendly, professional assistance.

Now you know what “flashing” is and how magnetism is used to run a generator. If your generator doesn’t initiate at start-up, you’ll have an idea what’s going on—and who your first call should be.