The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!


2017 NEC and Related
2017 NEC
Now Available!

Recent Posts
Parking lot pole light swap....
by gfretwell
Yesterday at 08:46 PM
International Wire Colour Codes
by Tjia1981
10/23/16 12:08 PM
Son of Sparky
by HotLine1
10/20/16 07:43 PM
Speaking of Plugmold ...
by gfretwell
10/17/16 02:37 PM
Broken battery charger? Check for cobwebs!
by gfretwell
10/17/16 02:30 PM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 14
ghost307 7
HotLine1 7
renosteinke 6
Potseal 4
Who's Online
0 registered (), 301 Guests and 5 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#185862 - 04/01/09 09:15 PM RE: My power supply post
LoneGunman Offline

Registered: 10/02/05
Posts: 141
Loc: Florida
The webmaster of a small home plating website claims to use multiple variable voltage/amperage power supplies, he says he wires them up in a "master and slave configuration", because we need current more than voltage I'm assuming he's somehow wiring multiple supplies in parallel. Opinions on this?

So the power supply has 120 volts going in and two terminals supplying 12 - whatever volt DC. I obviously know how to wire batteries in parallel but how could power supplies be wired in parallel? I mean I cant take the 12 VDC + from the first PS and wire that to the 120v input, what am I missing?

He claims to be using 3 70A power supplies to provide him with 210A.

#185868 - 04/02/09 01:39 AM Re: RE: My power supply post [Re: LoneGunman]
JoeTestingEngr Offline

Registered: 11/04/05
Posts: 786
Loc: Chicago, Il.
You can usually parallel the outputs of DC supplies but might have issues with different types. Getting the current shared equally is one. A bummer with high current supplies like you mentioned, is that it takes a ridiculous amount of capacitance to filter the output. This is especially true of a linear supply with 120Hz ripple. The 3 supplies would do well for you if they were fed from three phases and each had full wave outputs. The ripple frequency would increase but the ripple amplitude would be greatly reduced.

#185875 - 04/02/09 09:40 AM Re: RE: My power supply post [Re: JoeTestingEngr]
gfretwell Offline


Registered: 07/20/04
Posts: 9026
Loc: Estero,Fl,usa
Way back in the olden days when we had massive power supplies in computers they ganged several supplies together with short pieces of nichrome wire that acted as a resistor to balance the outputs.
Greg Fretwell


ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals