Selection of a motor

Check the following motor parameters to find out whether a motor is suitable for operation with an EP7402. A motor is only suitable if all motor parameters are within the permissible range.

The permissible ranges for the individual motor parameters can be found in the technical data:

Motor type

The motor must be a three-phase BLDC motor without an integrated motor controller.

Winding inductance

The winding inductance of the motor must be greater than the minimum permissible winding inductance.

Electrical time constant

The formula for calculating the electrical time constant of the motor is:

 

Selection of a motor 1:

τ : electrical time constant

L: winding inductance

R: winding resistance

The electrical time constant must be greater than the PWM period duration:

 

Selection of a motor 2:

τ : electrical time constant

fPWM: PWM clock frequency

Nominal speed

The nominal speed of the motor must be less than or equal to the maximum achievable speed.

 

Selection of a motor 3:

nmax : maximum achievable speed

frot : rotating field velocity

p : number of pole pairs

i: gearbox ratio.
    Example: i = 2 for a transmission ratio of 2:1.

Nominal current

The nominal current of the motor must be less than or equal to the maximum continuous current that the EP7402 can supply.