What kinds of electric car motors are the most popular for conversions?
There are a lot of electric motors out there, but just a few make up the majority of the motors being used in electric cars: the series wound DC motor, the permanent magnet motor, and the 3-phase AC motor. We'll talk about the pros and cons of each of these three types here.
When people choose a motor for their car, they're balancing factors like:
Note: A lot of people are using LEAF and Tesla salvage for motors in their conversions now. I'm not covering those types here, but a motor specifically designed to move an electric car is the best option (when you can find them).
This motor is the king of electric car motors. It's also the king of torque! The electric drag racers burn a lot of tire rubber with this motor, and if laying down long black tracks and clouds of smoke is your thing, this is the motor you want.
You've no doubt heard about this famous characteristic of electric cars. It's really a characteristic of these series wound DC electric car motors, though, rather than electric cars in general. These motors happen to be popular for electric drills, too, and that's why.
The Electrical Engineering training series says, quote: "Series motors cannot be used where a relatively constant speed is required under conditions of varying load." Unfortunately, that pretty much sums up what an electric car would be doing in hilly terrain, like my neighborhood. The DC series motor in your NEV might not climb those hills too briskly. Oh, you noticed this already? So did Zenn and Miles, actually...after 2008, all their new cars have AC drive systems installed.
Meaning, when you're installing your shiny new Netgain motor in that Chevy S-10 you've so carefully de-ICEd, you don't wanna hook the motor up to 120 volts and just whizzz it out attached to nothing (you know, to hear what it sounds like running); it'll take your head off. Apparently it turns with enough force to even damage itself if you run it without a load. You might never do this. Okay. But it also means that you can't use it with a belt drive, or a drive system that could fail like a belt could and leave your motor flying with no load - because it would destroy your motor if it failed.
The Advanced DC Series wound motor is by far the most popular of the electric car motors, according to the EV Photo Album, followed by General Electric motors and NetGain motors. If you're buying them new, you find these through local EV parts suppliers - there's a list of US NetGain dealers here.
Per-mag DC: These are the second most popular electric car motors in the EV Photo Album, but that's not necessarily because they're the best thing going.
The biggest drawback with permanent magnet DC motors? They're noisier. Like all brushed DC motors, the brushes generate electrical radio interference. But unlike other types of brushed electric motors used in electric cars, like the series wound DC motors above, which have windings which provide natural filtering of electrical noise, the PM motors have no natural filtering effect in their design...so they're noisy.
Most of the EVs with Permanent Magnet DC motors you find in the EV Photo Album belong to "small-ticket" EVs: bikes, motorcycles, scooters, and the like.
Per-mag AC: A lot of the drawbacks of Per-mag DC motors have been eliminated with design and control improvements of Per-mag AC motors. These are gaining popularity in the commercial electric car market, and with good reason!
Third most popular electric car motors for conversions, but if all motors cost the same, I think these would be the hands-down winner. Why? Because they're better. (There, yes, I said it. I took a stand: )
This motor uses the same batteries the DC motor does; a DC power source. The difference is that an inverter takes the place of the controller you see in DC drive systems. The system overall is a bit more expensive, primarily because of these sophisticated inverters...but you get your money's worth.
I'm very enthusiastic about these, it's no secret (check out my Best EV Motor Yet pick)! Why?
All these things add up to an electric car that's considerably more like the familiar gas-gobbler's performance.
Metric Mind's FAQ has a lot more to say about the advantages of AC drive systems over the typical series wound DC electric car motors and controllers you often see in electric car conversions.