At 07:17 AM 3/10/97 +0000, you wrote:
>I took care of that, and continued my investigation, I >determined that under
>no load and a HV DC of about 4300->4400 volts being produce by a line voltage
>of 238 volts. >At full load I measured the line voltage and it dropped >to
>229 volts, thats not bad since the line current is >about 45 amps. So the
>problem is NOT primary line sag.
Remember you are checking a capacitor input supply, which relys on peak
line voltage. The supply presents virtually no load at all to the power
line except at the crest of sine waves. You can have considerable loss
or clipping of sine wave peaks and it will barely change the voltage you
measure with a RMS meter.
In order to measure line regulation properly when a capacitor input
supply is used, you need to use a peak detecting voltmeter. It is the
regulation on peaks you are interested in!
>Bill Orr claims in his book, that the regulation of the >DC from the
>rectifier is much tighter when the increase in filter capacitance.
I don't have his book, but if that is a direct quote it is incomplete.
There is a plateau reached where additional capacitance will not improve
regulation. Adding capacitance far beyond this point causes problems,
and can not improve regulation.
That point is determined by the ESR (equiv series resistance) of the
power lines, transformer, and wiring.
The ESR includes leakage and parasitic reactances.
With a good supply and power line you should be able to hold voltage
within 10%, 5% is unrealistic at the power levels you are dealing with,
but you could do as well as five percent with low power (less than 1000
watts input).
73 Tom
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