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### Author Topic: Another Power Supply  (Read 3591 times)

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• 4,895
##### Another Power Supply
« on: February 11, 2011, 01:39:07 PM »
There is a red, a black and 2 white wires on the primary side of these.
How would i connect them to 110V ? Is 220v also possible ?

The board these are on has multiple outputs.
5v, 12v, 28v and 56v.

Can these two transformers be wired together somehow to get 56v ? (110v or 220v primary) What would the available current be ?

Thanks

#### RICH

• 7,380
##### Re: Another Power Supply
« Reply #1 on: February 12, 2011, 09:04:53 AM »
Russ,
You have a primary and a secondary on the transformer, so the primary is rated at 120V 1.7A, then the voltage is reduced by the turns ratio of the secondary which gives a decrease in the voltage to 20V but the amps go up.
A  transformer transforms voltage and current to higher or lower levels but the power doesn't change because it can't create energy.....if that makes sense .....
power out cannot exceed power  in.
Don't remember / not sure on this , but you can wire  transformers in parallel and get 20 volt 10A.

Look up the transfomer and see if you can find any info on the wiring.

I am sure the electrical folks in here can be of more help.

RICH
PS: My electronics and electrical knowledge is leaving me due to non- use so now i am only getting more dangerous
« Last Edit: February 12, 2011, 09:25:52 AM by RICH »

• 4,895
##### Re: Another Power Supply
« Reply #2 on: February 12, 2011, 02:51:18 PM »
Hey RICH, hope you're feelin better.
I pretty much figured the  primary to be two windings that I'd wire in parallel. That works with 110v OK

Googled around a bit and found that I can connect the dc output of multiple power supplies in series to output the total of all used. This works here too.

So, now I have a 56VDC PS and assuming it is 5A.

PS: My electronics and electrical knowledge is leaving me due to non- use so now i am only getting more dangerous
The lack thereof is my problem, my insurance premium is high due to the multiple fire hazards that I've created.

Thanks for the inpurt RICH,
Russ

• 4,895
##### Re: Another Power Supply
« Reply #3 on: February 12, 2011, 03:01:27 PM »
« Last Edit: February 12, 2011, 03:16:59 PM by Overloaded »

#### RICH

• 7,380
##### Re: Another Power Supply
« Reply #4 on: February 12, 2011, 03:23:38 PM »
Good post Russ. Most of the power supplies i have ever built were based on what is in the Amateur Radio Handbook. Has numerous excellant examples.

Yep, feeling 100% now. Darn, never thought the flu could kick one so hard, i couldn't even touch the hair on my head as it was painfull to my scalp.
And the worst part is you can't do a whole heck of a lot about it.

Right before i got the flu i took the mill apart to replace the axis bearings , now i got more crap all over the place and stilll getting nothing done!
I guess that's why it's called a hobby on this end.
RICH

#### Tweakie.CNC

• 8,022
• Super Kitty
##### Re: Another Power Supply
« Reply #5 on: February 14, 2011, 09:11:55 AM »
Hi Guys,

Just a word of caution for others following this thread - some power supplies, such as those used in PC's, may have the output negative connected to the outer casing so if wiring two units in series the casings have to be electrically isolated from each other and the high end unit isolated from Ground or a short will occur. This doesn't apply to all power supplies but it pays to check first

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.