RE: [CAD_CAM_EDM_DRO] Re: QUESTION ABOUT SERIES OR PARALLEL ON STEPPER MOTORS - ref post 52721

I thought I was understanding this and all of a sudden I'm confused again.
I thought that the ratio of DC voltage across the bridge rectifier (across
the cap) was 1.414 times the secondary AC voltage of the transformer. For
example,

My two tap combinations assuming my line voltage is 115 volts:

Primary Tap Secondary tap Measured secondary voltage X 1.414

115 volt AC 44 volt AC 44 volts AC X 1.414 = 62 volts DC

or

105 volt AC 44 volt AC 48 volts AC X 1.414 = 68 volts DC


Am I wrong in the above?

Thanks for checking my figures.

Regards,
Jeff

-----Original Message-----
From: turbulatordude <davemucha@...> [mailto:davemucha@...]
Sent: Thursday, February 13, 2003 8:36 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] Re: QUESTION ABOUT SERIES OR PARALLEL ON STEPPER
MOTORS - ref post 52721

I can't recomend anything about the capacitors, but you are correct
in that voltage it the key. if they worked at higher, you did verify
they did work actually at those high voltage right ?

regarding power, if you plan on the geckos, 80 volts is the max.
divide by 1.414 to determine DC voltage bofore the caps. the caps
will increase the DC to near peak values and not RMS so you pick up
the 1.414 times raw DC.

If you can cut the DC to 56 volts, you will be good. if you want a
little more, you can put a terminal connection on 56 volts, then wrap
a few turns and add another termianl. it would let you get closer to
the 79.999 people shoot for. and it would allow you to correct for
losses from the diodes/rectifier.

Dave






--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Jeff Goldberg" <jeff@w...>
wrote:

> OK. Sounds like a reasonable thing to do.
>
> Back to one of my original questions:
>
> Since I can modify the power supply somewhat, and since the max

drive

> voltage is 80 volts, should I supply 62 volts, 68 volts (or some

other

> voltage which would mean I'd have to scrap the power supply and use
> something else). Also, I've seen calculations on how to properly

size a

> capacitor for a DC power supply. There is a capacitor (unmarked of

course)

> about the size of a beer can with a 1K ohm resistor across it on

the DC side

> of the power supply. Can I assume that if it worked OK at 130

volts DC, it

> will be OK at about 1/2 the voltage?
>

<snip>