I'm planning to develop a control circuit for a 24V, 500 RPM (@no load), 2A, 4 kg-cm brushed DC motor. Motor has to run only in one direction. I plan to use IRF44ZN MOSFET with a proper driver to drive the motor and a PIC 16f873a to generate PWM. But the challenge is, the motor has to be continuously operated for at least one day (24 hours). What are the things that I should taken care of when designing a drive for such an application?
Electronic – Design Considerations for a dc motor drive circuit
dc motorgate-drivingmosfet
Best Answer
Here are some of the things I think about when I need to drive a motor:
Motor overheating:
Is the motor sufficiently rated to continuously handle the maximum load at the minimum required speed? (Although this technically requires less mechanical power, the "self-cooling" is less, so it may get hotter).
is it better to run at the requested speed for as long as possible, until the motor fails? Or is it better for the system to refuse to run at the requested speed when the motor appears to be overheating, slowing down or stopping to protect the motor?
Transistor overheating:
What happens if the wires running to the motor are shorted out? Is this so unlikely that it is OK if the transistor blows up? Or is this so likely that it's worth designing the system to measure the output current and turn off the transistor when it reaches the max current limit?
How much voltage is required to turn the power FET "all the way on"? Can my microprocessor turn it on adequately, or do I need connect the gate of the power FET to some higher voltage -- perhaps 10 V or 12 V?
Other considerations: