Motor Driver Selection

[dunkonu]

Hi,
I have chose the motor for self-balancing scooter. The spec of the motor can be seen in the attachment file.

Right now I have to choose which driver is suitable for my motor. I have narrowed down to three drivers and the specs are:

Type: LW24VFR
Weight: 540g
L*W*H: 120mm*98mm*41mm
Current Limit: 75A
Continuous Current: 20A
Direction: Forward/Reverse
Nominal Battery Voltage: 24Vdc
E．M Brake(24Vdc): None
Suitable Motor: 600W Below

Type: LW24VGB
Weight: 1KG
L*W*H: 162mm*115mm*56mm
Current Limit: 120A
Continuous Current: 40A
Direction: Forward/Reverse
Nominal Battery Voltage: 24Vdc
E．M Brake(24Vdc): Yes
Suitable Motor: 600W Below


Type: LW24VG
Weight: 880g
L*W*H: 142mm*115mm*56mm
Current Limit: 70A
Continuous Current: 20A
Direction: Forward/Reverse
Nominal Battery Voltage: 24Vdc
E．M Brake(24Vdc): Yes
Suitable　Motor: 450W Below


Can anyone give me some ideas or suggest which driver is the best match with the motor? Why?

Thanks

[Matt H.]

Although I am certainly not an expert here are my thoughts.
All drivers are the same in nominal voltage and forward/reverse so those variables do not need to be considered.

I would not consider LW24VG because it is heavier larger and less powerful than LW24VFR offer no advantages over it and narrowing the contest to the first two.

Since your motor is rated for a max of 23 Amps and at max power should only be drawing 17.5 Amps (420watts/24v) then there is no need for an operating current above 20Amps. Unless your scooters is very poorly designed the motor shouldn't run at much more than 15amps continuously.

Therefor I would use LW24VFR for its low weight and size.

(A note on electronic braking) Electronic braking can never bring the speed of a motor down to zero (look up the physics of a motor with leads connected). In any case a scooter will require some kind of frictional brake so I don't believe electronic braking to be an important feature.

[Jim E]

Because of the 23A rated current at 24V, I would tend to go with the 40A controller over a 20A.

Motors tend to have current spikes when starting and reversing direction. The added robustness of the 40A controller may save you from having to replace speed controllers if currents exceed 20A.

[Matt H.]

Jim E. I believe those current spikes are taken care of by the spike current allowance of 75Amps on the first controller. There should be no instance of a sustained current of above 20Amps (in my opinion).