The scenario
A conveyor belt system uses a 60V SMPS to drive a brushed DC motor. When the run switch opens, inductive back EMF can damage the supply and switch, so a Schottky diode and varistor clamp the transient.
What is in this drawing
Read the decisions behind it.
01
Schottky diode placed anti-parallel across motor terminals to clamp negative inductive flyback
02
Varistor across motor terminals to absorb high-energy transients and protect against overvoltage
03
Fuse and bulk capacitor on SMPS output for overcurrent and input ripple
Use for single-quadrant brushed DC motor drives powered by SMPS where back EMF protection is required, e.g. conveyors, pumps, fans.
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