On 20 Jul 2005 18:29:20 GMT, (Chuck
Sherwood) wrote:

So I can parallel either diodes alone, or rectifier blocks to get
increased current capability? I understand about the cascade failure

You cannot parallel diodes directly because they will have a small
voltage mismatch and one diode will hog all the current. You
can only parallel diodes if you force them to share current
by putting a small resister in series with each diode.


if one should go. Since the charger has about 6 taps on the primary,
for increasing rate of charge (simply higher voltages) can't one just
select a lower setting and ignore the voltage drop the old selenium
rectifier had?

Seems very reasonable and worth a try.


Chuck,
I built a three phase rectifier that used 4 1/2 bridges. Actually, I
had 9 winding to contend with. This rectifier assembly is being used
to power the servos in a CNC conversion. If one diode hogged all the
current it would have blown already. Am I just lucky? The rectifier
bridge assembly recieves 90 VAC from the xmfr. The servos draw 15 amps
max. The output from the rectifiers goes into an electrolitic cap for
filtering before going to the servo amps. Should I put resistors in
between the diodes and the xmfr? If so, what values do I need?
Thanks,
Eric R Snow