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HOW do you select a pmdc MOTOR for an electric vehicle? Answered

Suppose we are up to making an electric vehicle and needs to set up the parts correctly.HOW  do you then select the dc motors of appropriate ratings.Like for a 48 v  PM DC what amount of load can it pull and stuff like that?



6 years ago

Often you don't get your ideal motor and have the choice of only two or three.

A performance sports car being manufactured in the west out performing
the BMW in acceleration and top speed is using a wound stator in order to
perform the low speed acceleration.
You and I would be happy to use a plain PM field with a single efficiency point
and adjust the gearing to put the vehicle traveling speed into that peak
efficiency for the best extended battery range.

I used an old VW placing my motor to drive the spline of the four speed
transmission giving me three peak efficiency traveling speeds.

The battery in the car I speak of is using a floor liquid cooed Li Ion C cells
( I could be wrong about the cell size ) giving the car the lowest center of gravity.

Most car designers don't have the wherewithal to use Li ion and end up using sealed lead acid Gates cells for batteries or even deep discharge 
car batteries.


but we need to convert an tandem recumbent tricycle in to an electric bike,with back to back positioning of two drivers and both must be either able to control simultaneously or one at a time.And we need to install some sort of mini KERS in order to boost the acceleration using the energy dissipated in braking.And have no idea about what kind of batteries are used for electric bikes!
i need some suggestions!

Here then is the first suggestion for you to consider.
Use a hub motor kit which has worked on many a
riding couch ( 2 or 3 people ) at burning man

The pic is a double of the $260 Amazon
Brushless Electric Bicycle Engine, 48v 500w Rear Wheel Hub Motor Kit



would you be able to power a geo metro off a starter motor from a v-8 engine if you get enough batteries and put ball bearings on the motor?

You need to start by knowing quite a lot about your vehicle. How much it weighs, What the drag factor is How fast you expect it to go, How far you expect it to go.

Once you have this data you may be able to make a comparison with other similar vehicles.

The electric car I was involved with had a 250 watt continuously rated motor. With this it would reach 30 MPH It weighed with driver and battery about 100 pounds. Drag was low. No actual figures available.

Many commercial vehicles have motors of 80 KW peak power but are a lot heavier


Hi rick

Thank you for your valuable suggestions.But we ain't making an electric car.We are making an electric trike(tricycle) and supposed to by driven by two people simultaneously or one at a time.Both conditions must be satisfied.we are making the trike with pmdc motor(400 w) at the rear end!and need to install charging facilities for the bike.Do you any trikes there that have KERS installed on it?we do have such an option on our mind