Topic: Fitting a motor to a vehicle.

[piersdad]

Fitting a motor  to a vehicle.
A motor generally has a rated voltage and current. Horsepower or watts

The voltage  relative to its speed at that voltage depends on the number or wires in each slot of the armature this is a fixed thing that can only be changed by a rewind.

The current  rating represents the maximum magnetism the coils will deliver with out saturating the iron.
Further current  tends to cause heating instead of torque  so if the max current is exceeded the torque will increase but inefficiently.

So the first thing to find out is the speed you want the car to go and the gear ratios available.
This will enable the speed of the required motor.
If for instance the required speed is 2000 rpm and the motor is rated at 1500 rpm at 24 volts  so at 32 volts the motor will deliver this speed.

In another part of this site is finding out what the power requirement buy towing your car at required speed and measuring the tow bar  force and from this the required  wattage the motor has to deliver to power the vehicle.
rolling resistance of electric cars

So  if this wattage  is 4800 watts then at 32 volts the current will be 150 amps.

So a ex 24 volt motor at 150 amps will get you going.

However this is a high current and by using a higher gear from a gear box then with for instance at 2 to 1 will give 4000 rpm 64 volts and 75 amps  and this will be a more sensible current and voltage.
The 4000 rpm is near the limit to what was a 1500 rpm motor so   it would work but not too much  more however the current will be half the normal max and therefore accelerating will be more brisk and efficient.