My Generator Alternator Brushes Keep Melting or Wear Very Quickly

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Turn off the Generator immediately and do not use as this might cause damage to your equipment!

This will most likely be caused by one of the following reasons:

1)  Overloading the generator – Breakers do not protect you from overloading, only from surges.

Be sure to take surges into account when calculating what can be run on your generator. Please be aware anything with a motor could have as high as 100% of the surge value of their running watts (i.e. Fridges/Freezers, Compressors, non-soft-start AC). Any electrical items that produce heat are most likely over 1500w (i.e. coffee maker, hair dryer, kettle). Also, welding often requires higher currents than portable generators will produce, it is better to use a welder generator than to power a welder with an ordinary portable generator where overload is very likely.

2)  Starting the generator with equipment plugged in and breakers on – Turn off all Breakers and unplug all equipment when starting. (This is a very common reason for overloads!)

3) The generator is not grounded – All generators should be grounded during operation as per instructed in the manual. If there is a surge it needs to be sent to ground to prevent damage to the alternator and prevent electrocution!

4)   Equipment that is powered by the generator has an electrical fault and is surging beyond the capacity of the alternator – All equipment should be tested on a regular basis. If you can smell the electrical burning scent around equipment, or issues only happen when certain equipment is plugged in, this is a good indication of an electrical fault within that equipment.

5)  The generator was manufactured or fitted with an inferior quality alternator and this has degraded – This is not uncommon on budget generators.

6) Your generator is unbranded, rebranded, and is not actually the Wattage it has been marketed to be – This is common with cheap generators bought on eBay, Amazon, random small websites or from “on the side of the road” independent vendor types. If you think the generator is small in size or very cheap compared to other similar wattage generators, there is a good chance it has been incorrectly labeled as a larger generator. Please contact us for more info and we may be able to identify it for you.

7) You have a single-phase generator that has been rebranded as a 3-phase generator – Again, common with cheap generators bought on eBay, Amazon, random small websites or from “on the side of the road” independent vendor types. A common feature for some of these incorrectly marked generators is a red socket on the control panel. Please contact us for more info and we may be able to correctly identify it for you.



Brushes are only found on alternators with an AVR. Unlike other Alternators, these connect to the Armature directly via the Brushes.

If your brushes have “melted” this is an indication of one of the following:

– Alternator overheating due to poor or low airflow

– Alternator overheating due to Overloading

– Alternator failure (the most likely cause)

You will need to either replace the Alternator or take your Generator to a nearby Motor Rewind Company to be repaired.

If you would like to confirm this diagnosis, please run the test in the following section.


Alternator Testing on a Portable Generator

If you think you may have further problems with your alternator, you can view this more in-depth article on testing and diagnosing alternator issues here.

Spanner Driver QUESTION

Did this fix the problem?

Spanner Driver Answer

Yes. I’d like to buy new parts to fix my generator now.

Spanner Driver Answer

No. I need more help please.