Basic DC motor question

AC, DC, amps, volts and kilowatt. It's all discussed in here
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Joined: Tue, 24 Mar 2009, 16:05

Basic DC motor question

Post by Benjamin »

Hi EV people.

I'm mad keen on having an electric car and am looking to do my own conversion of something small using a DC motor.

I've been doing some research, mostly the electricity4gas manual (from website of same name), and understand the general idea.

I'm left unclear on the precise specifications of the kind of DC motor that is appropriate.

Basically, what's important here? kiloWatts? Amps? Voltage? RPM? How many of each is about right to drive a small car around town?

... so I know what I'm looking for when I trawl 2nd-hand DC motor sites.

Thanks for any help folks.


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Joined: Mon, 23 Jun 2008, 15:12
Real Name: Taffy Flynn
Location: Melbourne

Basic DC motor question

Post by Taffy »

Using the spreadsheet on the bottom of this page: ... Drive.html
Direct link:

Calculate how much power you need to achieve your desired target speed, range and acceleration.
You can also get your rpm at the same time but updating the details to suit. Ingore the other tabs as they are for AC stuff.

Take a look here:
To get a good idea of how big of a motor you are looking at, find the weight of your vehicle and then look at the motor specs.
For ~1200kg car with moderate acceleration i guess your looking for around 9kw continuos.

Some basic ideas:
Volts = top speed
Amps available at once = acceleration
Amphours = range

Another option but in mph,ft, inches and pounds... all very annoying to work with :(, but very useful none the less:

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