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Help with high voltage power supply

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New Member
Hello, I need some assistance on a circuit i have for a high voltage power supply, using a bridge rectifier. There are several things i need to know :eek:

What reverse voltage ratings would the diodes have for reliable operation? (I thought that as the voltage through the diodes will be 240V, it would be double that to ensure reliable operation?) Also, the current rating they should have?
I then need to know the working voltage of the smoothing capacitor and the ripple percentage when the motor is running and not running? I have completely forgotten the formula for this.

Any help would be greatly appreciated,im at my wits end!!

I have inlcuded a drawing of the circuit:

direct link http://img36.imageshack.us/img36/479/img001wre.jpg
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Well-Known Member
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PIV of the diodes in the bridge needs to be greater than 2.8 times the rms V of the transformer secondary. Google and Wiki is your friend. Current rating of the diodes at least 10X the motor running current (for motor starting).


Solve for C = I*t/ΔV. You get to pick ΔV (ripple). I is motor current. t is time between full-wave rectified pulses at 500Hz, ie 1ms.

Voltage rating of the capacitor greater than 1.4 times the Vrms of the transformer secondary.
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