RE: [CAD_CAM_EDM_DRO] Re: current rating of transformers

I still think those 1.8 figures are telling you how to figure out what size
capacitor to use...

Andy Wander
Verrex Corporation


-----Original Message-----
From: turbulatordude [mailto:davemucha@...]
Sent: Monday, October 25, 2004 2:31 AM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] Re: current rating of transformers

> >This is where I'm confused.
> >
> >If I use the full winding, 24 volts, do I really get 5.8 amps ?
> >and with center tap, 12 volts, 8 amps
> >but using a choke at 24 volts, I can get the full 10 amps ?
> >
> Yes, probably. But, inductor input filters usually have poor

regulation,

> meaning the voltage droops substantially under load. But, the peak

currents

> in the transformer will be greatly smoothed out, so the RMS rating

of the

> transformer is fully available. Capacitor input filters draw

strong pulses

> of current right around the voltage peak, and this is a worst-case

situation

> for copper losses. So, all capacitor input filters will deliver

less

> current
> from the transformer for the same heating.
>
> Jon

It sounds like a trade-off. Higher rating with an inductor and
better regulation with a CAP.

What really bothered me was that the printed catalogue is the only
place I found any notes about this and it sounds like if I need 10
amps output, I need to multiple my required amps by 1.8 and then
order the transformer for that much higher rating. The way is is
written, it sounds like I get 1.8x the listed amps. Darn confusing.


Thanks for the information.

Dave