Transformer primary

[mccannsp]

I have a 13.5 V 20 Amp transformer that I am trying to connect to a three prong plug and I am having trouble. The X-former has black, brown, and white wires for the primary and my plug has white, black, and green. I know for sure the green on the plug is the third prong (ground). Is there anyone out there that can help with connections by color code.


Thanks

 

[gerty]

An ohmmeter will tell you what you need to know..Is the transformer a single voltage primary? It may have a 110v and 120v primary, I have one like that , and you can wire it for either, the output will be slightly higher if you feed 120v in on the 110 winding. It probably a safe bet that one of the primary connections is the white, using an ohmmeter connect from white to brown. Then connect from white to black, the higher resistance should be the 120v, the lower resistance 110v. If one lead is ground you should read continuity from the case to this wire..If it's a
120/240 primary the high resistance connection will produce only about 7v
on the secondary..

 

[Klaus]

From the description of your three prong plug wire colours I gather you are in America.
As far as I know there is no fixed colour code for transformer wires, I've seen all sorts of colour combinations, on transformers from your country and from other countries.
Since you know what the secondary voltage is supposed to be you can find the correct wires by trial and error.

First, with an Ohmmeter find the two primary wires with the highest resistance between them. Connect them to your plug's white and black prongs (via a fuse preferably). Then measure the transformers secondary voltage - it should be slightly higher than spec since there's no load on it.
If this is the correct voltage you're done, if not, repeat above with the two wires having the second highest resistance between them.


Klaus

 

[ChrisP]

Do you have any manufacturer and model info on this transformer?