Re: [CAD_CAM_EDM_DRO] Where to buy transformers?

DeLesley, when you know the required DC output voltage, say your 48 VDC
listed below, multiply
the 48 VDC by 0.707 to get the AC RMS voltage required. In this case 48
times 0.707 equals 33.936,
so some where arround 35 volts AC would work. The RMS voltage of 35 VAC
multiplied by 1.414
(to get the peak voltage), equals 49.49 VAC peak, and the peak equals the
output DC voltage less any
rectifier voltage drop and the voltage drop across the resistance of the
transformer wires etc,.and with the
proper sized rectifiers, transformer and filter capacitors,.

Multiply the RMS voltage by 1.414 to get the PEAK voltage and
Multiply the PEAK voltage by 0.707 to get the RMS voltage.
The DC output voltage equals the PEAK voltage less any drops accross any
resistance in the circuit.
Dave

----- Original Message -----
From: "ds_hutchins" <hutchins@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Monday, August 05, 2002 16:10
Subject: [CAD_CAM_EDM_DRO] Where to buy transformers?


>
> I'm thinking of building my own power supply, and I need to find a
> transformer for a reasonable price. While there's been a lot of posts
> on the list that discuss transformer types and/or sizes, I couldn't
> find any links to places that actually -sell- them at reasonable
> prices. The standard online electronics houses (e.g. mouser &
> digi-key) don't seem to carry large power transformers. I'm looking
> for something in the 500VA - 1000VA range. Toroidal would be nice, but
> I may go with the "normal" kind for price reasons.
>
> As to size... I just purchased 3 DC motors that run at 40V nominal,
> 60V max, with a peak current draw of 14A/each. The guy I bought them
> from recommended that I run them at 48V for CNC use. I know that I
> won't ever run all three at peak current, but would a 10A (500VA)
> transformer actually be sufficient, or should I shell out the $$$ for
> a 20A unit?
>
> Also, I've seen several posts that say I should multiply the AC
> voltage by 1.41 to get the DC rectified voltage. In my electronics
> books, however, it says that most AC voltages (such as the 110V
> household voltage) are already specified in rms form. When I'm buying
> a transformer, do I get a 48V secondary, or a 34V secondary?
>
> Thanks!
>
> - DeLesley Hutchins
>
>
>
>
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