transformer

[lgalla]

I have some old transformers with many taps.How do you determine which are the primary windings?
The wires are ....2 green 2yello 2red 1 white 1 black 1 brown
Larry

[Al_The_Man]

Usually the secondary's are wound last, so these may be identified that way, most likely the green and the yellow for sure.
Primary white black red could be 0-120-240.
The first thing to do is to take a resistance reading of all winding and find out which are common to each other.
For example, if I am right on the W.B.R. then they would all show continuity between each.
If for example there were 2 ohms between white and Black and 2 ohms between black and red, and 4 ohms between white and red, then the 240v would be across these two and 120 across either of the other pair.
The brown, not sure, again a resistance value may enlighten.
Al.

[lgalla]

Thanks Al.Whats brewin?
If anyone in Canada wants to check out one of these transformers I will ship one free to check the specs.These must be very old as the buyer was Electrohome and the shipper Leigh Marsland.If they are useful as a small stepper supply,I will give them away to Zone members for S&H +postage from M4L1S6.All the wires appear to be solid 18 or 20 Ga.
The weight is 9Kg.Hope they are of some use to someone rather than be scrapped.I have 28 units.
Merry Christmas
Larry

[Al_The_Man]

I can check one out for spec's if you wish.
Al.