Large capacitor soft start circuit
I have a servo power supply that is simply 120vac rectified with a large capacitor (not sure of the value at the moment). I cannot switch this on directly without tripping breakers, burning contacts, etc.
I have a couple different circuits I have drawn out to soft start this, I am looking for advice on which route to go.
The first method would use a timer, switching a resistor out of the circuit after a preset time. Simple enough.
alternate method:
This seems like more of a direct approach to the problem, or maybe its just neater. There is 0v across capacitor at start and by the time a voltage has developed, the inrush problem is gone. So why not put a relay with a 120vdc coil across the capacitor? This would have the same resistor circuit as the first method.
Good or bad idea?
If you try to make everything idiot proof, someone will just breed a better idiot!