# Motor Stronger than Powersupply?

Discussion in 'Sensors and Actuators' started by S4ndwichGurk3, Jul 8, 2018.

1. ### S4ndwichGurk3

3
0
Jul 8, 2018
Hi,

I am currently making my own Racing Wheel for SIM-Racing games.
I have bought an H-Bridge that can handle up to 43A and I am looking forward to buy a 12V power supply (200-400W). Howevery, the motor I would buy has a stall current of 75.8A (12V). That would be like 910W. It's rated maximum Power is 463W (that's 38.6A then).

My questions: can the H-Bridge limit the current that is powering the motor or will the motor still draw more current from the power supply? In other words: will this system work if I have a lower maximum PWM-Signal?

I would run the motor at a lower power.
I hope you can somehow understand my problem and I appreciate any form of help.

2. ### Minder

2,948
623
Apr 24, 2015
That is most likely the stall at maximum load or when powered at full voltage.
If you have any kind of PWM or similar control, the current can be limited.
Do not turn on the power with the PWM set to max. IOW ensure o rpm at switch on.
Also a suitable fuse should be used in case of accidental over currents.
M.

S4ndwichGurk3 likes this.
3. ### S4ndwichGurk3

3
0
Jul 8, 2018
So I am totally fine with a lower PWM when the motor is spinning.
One more question:
When the steering wheel is turned 450° in one direction, the motor will block (stall) in order to stop the rotation (like a mechanical stop). Is it correct that I would have to set the maximum current to 43A through PWM when stalling, even if it is rated at ~76A?

4. ### Minder

2,948
623
Apr 24, 2015
If you are going to stall the motor, the PWM allowable current limit is to have to be either the rated continuous stall torque current of the motor rather than the peak allowable current, or the limit of the P.S.
M.

5. ### Bluejets

4,004
828
Oct 5, 2014
Might be obvious to some but what is the motor driving....?

6. ### S4ndwichGurk3

3
0
Jul 8, 2018
The motor is driving the steering wheel to act like a force feedback when racing on the PC. It will be connected with a belt.