Dirty Power to Furnace?

A week ago, the blower on our furnace quit working. It's a Rheem and is less than 5 years old.

Around the same time it failed, we smelled a hot electrical component and traced it back the furnace and its variable-speed, ECM-controlled blower motor.

I called a service tech in and he confirmed my worst fears. It was the ECM module that hangs off the rear of the motor. It cost $425 to repair, but is working fine again.

Perhaps coincidentally, the day before the failure, we had an abrupt power failure that lasted 4 hours. There was no bad weather that day and the power company blamed it on a "transformer failure." Power was out for 20 square miles.

I was a little skeptical because the power coop had a contractor working at replacing the entire service line for our canyon with super-heavy-duty lines around the same time.

Is it possible that a voltage spike triggered by this contractor could have fried my furnace's brain? Should I consider putting a surge protector on the power supply to the furnace?

All our home electronics are protected - but not the furnace.

Thanks for your help!