[bennelson]

Since Paul's motor controller project has me all excited about the possibility to upgrading to a higher system voltage for not too much more money, it's time to investigate what other things I need to do to go up to either 120 or 144 volts.

In my area, there is an "electrical rebuilder" who has been running his shop a long time. In fact, one of my brothers worked there for a few years way back when, and this guy is the uncle of a friend of mine.

The shop rebuilds automotive starters, various motors, and actually does a lot of work on higher voltage bus motors, including electric and hybrid busses - who knew!

I called over there, but he was busy, and I left a message. I was surprised to get a phone call back last evening.

I explained what I was doing, having built an electric car last summer, running it with a forklift motor at double its designed voltage, and wanting to take that even further.

Interestingly, the first thing he asked was how much money I had put into the motor. "Not much". I only spent $50 for the motor and another $50 for a brand new set of brushes.

His premise was this - If I had spent lots of money on a fancy EV motor - DON'T screw with it!

If I have only little money in the motor, go ahead and experiment. He told me that the forklift motors are beefy and can take more than you think they can. By severely over-volting the motor, I am getting into the realm of "experimental" and am designing what he called a "rat-motor", which has the potential of being very powerful.

He said the main concerns are that I would suddenly have the urge to go fast, peel away from stops, and drive fast and hard for long distances. As long as I could resist those urges, the motor should be fine.

A while back, when I got a message from Jim Husted about forklift motors, he said that mine should handle 120v no problem.

The local rebuilder said that I should just shoot straight for 144V.

I did notice on the EVDL mention of drilling a small hole into the back of one of the brushes to insert a temperature probe. Brushes are the first thing to heat up when you are trying to burn out your motor.

I have NEVER had any issues with heat in my car. NONE. The Curtis controller (without a heat sink on it even) has only ever been slightly warm to the touch after a long ride. The motor has NEVER been even slightly warm. I was told that most of the noise from my motor is from the big aluminum fan blade on the drive end of it. When we built the new motor end mount, I made sure to cut the center hole extra big to allow for air circulation through the end vents.

I believe I have an excellent motor to "rat-up"

[begin evil laughter...]


PS - The electrical rebuilder is also converting a Prius to plug-in, from scratch, using a 20KWh lithium pack. That thing should do 60 miles without gas! I will try to find out more on that project as it progresses!