Planning a budget EV build

[bennelson]

On my motor, I pulled off the ends, removed the rotor (gently, don't let it bang around as you pull it out!) then removed the bolts that hold in the field coil.

I hung the field coil from a tree and used a can of spray-on electrical insulator to recoat the insulation. It looks like green spray paint, but is actually a good quality insulator. I got it from a friend, but I think a can of it only costs like ten bucks.

I also inspected the bearings in the motor, which were fine and did not need replacement.

I visited a local forklift motor repair shop, where I got new brushes for the motor. Half the total cost of my motor was new brushes! ($50 for the motor, $50 for the new brushes!)

While I was there, I told them what I was doing and asked for advice. The guys showed me the machine they have for re-cutting the grooves on the commutators, but that you could more or less do the same thing by hand with a pick or hacksaw blade.

They also gave me a "Commutator Stick" which looks like a cross between a nail file and a lipstick. It's an abrasive material which you simply press against the commutator as it spins to smooth it out.

The commutator was cleaned up by a friend while he had my motor for helping design the adapter plate. He had a lathe, so he just zinged off the tinniest bit of the commutator to reveal fresh, clean copper.

I cleaned out the commutor grooves with a pick.

I ran the motor on my shop floor at 12V. With the new brushes, the clean commutator, and the grooves cleaned out, there was still a tiny bit of visible arcing and a little high pitched whine. (The whine was the motor, not me complaining!)

With the motor spinning, I gently pressed the commutator stick in there, rubbing it across the commutator. Instantly, the arcing and high pitch noise went away! I don't know what's in a commutator stick, but it sure worked great!

That commutator guide that Ryland posted looks like some good information.

Another place you might want to look is at a thread on DIY Electric car, started by EV Motor Rock Star, Jim Husted (username: Hi-Torque Electric.) He tells you how to pick a good forklift motor to convert to EV use.
Using a forklift motor, and choosing a good one - DIY Electric Car Forums

[Ryland]

The commutator stick that I've seen was a type of pumice designed for motors, I bought some from the motor shop in town for $10 per pencil size stick.
Tom at Helwig Carbon said that using pumice is not an ideal way to go but it does help with wearing the brushes in faster as well as removing burs, he also said that the clean copper of the commutator is higher friction and will run hotter then a commutator that has a film of graphite from the brushes and that letting the motor run at a low voltage with no load for a few days if possible is the best way to seat them in if you want to be assured that the motor will run cool and have long life.

SPRAYON Red Insulating Varnish, 20 oz. - Rubber Coatings and Insulating Varnish - 1D276|S00601000 - Grainger Industrial Supply

[puddleglum]

Thanks guys, that's the good advice I was looking for.

[MetroMPG]

Originally Posted by bennelson

PS - On small front-wheel drive cars, your motor limiting factor is the diameter of the motor (distance from center of transmission to half shaft on the motor side) and the length of the back of the motor to the wheel/tire.

Can confirm: we had planned to use the monster drive motor from the forklift for the ForkenSwift's motor, but its diameter was too large. Did not clear the half shaft.

Fortunately for us, (1) the smaller hydraulic pump motor was ideal for "plan B", and, (2) we found someone who wanted to buy the monster for a RWD project vehicle.

EDIT: puddleglum, have you picked a host vehicle yet?

[puddleglum]

I don't have a car yet. I've been dreaming of this project for a long time and probably will be for a long time to come. I just finally found a decent motor and I decided I couldn't pass it up. Hopefully it will be free once I sell off the rest of the forklift, and it is in really good shape. The brushes are good and the comm is smooth. It spins free and was quiet when in the forklift. I don't think it will need much.
I figure this way I can look for a car to fit the motor. Used cars are much more plentiful than used motors. I need a 4 door anyway. I'm thinking like VW Jetta size, so I think I should have room for the motor. I want it to be our main family transportation in town.

[puddleglum]

So, there is a low mileage PT cruiser for sale, but it has an auto. Could it work or should I pass? How much worse is an auto to do than a standard?

[mechman600]

It's been done. You lose efficiency/power/range, but it's doable.
Ecomodder member theSGC did a 1996 Civic auto. Here is his blog:
Civic Electric Car Conversion: How I Used an Automatic Transmission in an EV

And a good one from diyelectriccar.com:
The Reasons why Automatic Gearboxes WILL Work with EV's & how to do it.. - DIY Electric Car Forums

[puddleglum]

Thanks mechman

[puddleglum]

So, I'm just wondering what you guy's think. I've read through most of the threads on auto's and I think that I could make one work if I wanted to. Some guys are very happy with their's. The PT Cruiser is still up for sale, it is a roomy, stylish car with only 100,000 miles, but transmission aside, it's heavy and not very aerodynamic. There is also a 2007 Aveo sedan with a standard and 120,000 miles. A third choice may be a 1999 Protege standard with 140,000 miles. I'm hoping to look at them this weekend. Just curious, which do you think would be the better choice? Keep in mind it will need to house and take the torque of an 11" motor, and also fit three adults.

[bennelson]

I'd avoid the Aveo. A friend of mine had one briefly, and he felt it was a very low quality car.

Another friend of mine converted a Dodge Neon to electric, with no issues at all. The Neon and PT Cruiser are basically the same platform. I think a an EV-PT would be pretty cool, although the automatic isn't ideal, and like you said, it's heavier than a Neon.

I don't have any personal experience with Mazda's, but anyone I've known who has one likes it.