power supply

[boostdummy]

hi there all, i have been watching this group for a long time, and i now have a question that i hope some one can help..

I have a piece of equipment that needs a negative 48 volt power supply, dos any one have any idea how i would go about this.

Parts that i have is a transformer 50v 40A not center tap, the secondary only has 2 wires, i have a large asortmant of caps and high voltage diods and high curent diods..

But i am un shore of how to do this, the input to the telco equipment has group, common and -48v.

Thanks in advance..
Jason

[roddyama]

What is the wall voltage in Barbados?
What is the input voltage of the transformer?
What kind of equipment are you powering?

[boostdummy]

the wall voltage is 220, this input vlotage of the transformer is 210,220,230 or 240, the secondary is a 2 wire secondary no center tap, and the voltage is 50volts..

It is an ascend max modem bank.

[jackinnj]

to use a Texas Instruments TL783 high voltage adjustable regulator -- the transformer you are using will result in an output from the filters which will blow through an LM317HV. If you just require a "negative" voltage the "ground" becomes the positive output of the regulator.

You have to be very careful of grounds etc. when pulling a negative voltage from a positive regulator -- as all isn't as it appears!

See the TI website for details -- www.ti.com

[boostdummy]

the supply dos not need to be regulated.
and i do not know if you would do that easaly ether
as the equipment will draw about 20amps comstaly.

i know you are only going to use 2 diods insted of 4,
but i am not shore where to get the common signal from.

with a full wave bridge there is a + and a -
but with this there is a - where is the common (the other side)

that is where i am having my confusion.

[JOE DIRT®]

if its telco equipment maybe your looking at AC 48volts which is a standard???

[boostdummy]

no it is not ac, that would be a simple one then..
and man you really mad me hope, but no dice.
it is DC