Mystery Transformer

[dbishopbliss]

I have a power transformer that I don't really know anything about other than it came from a Conn organ. I don't know the model it came out of or anything. Its a pretty decent size and I'm sure it could be used for a guitar amp. I figure I will let the voltages dictate what amp I build next.


What is the safe way for me to determine the voltages and ratings of this transformer?

[Soulfetish]

If you've got a signal generator and true RMS Multimeter, use your multimeter to adjust the output generator's output to 1V RMS 100Hz-500Hz (or something).
Then clip two leads from the signal generator to the two black transformer leads, running a 1V RMS sine wave into that winding. Then use your multimeter to measure the voltages across each of the other windings. The 1V is an easy way of finding out what the turns ratio is for each secondary, and quickly calculate what the voltages will be at each of the other windings when connected to a live voltage of 120V(or 220V).

[sluckey]

First use your ohm meter to separate the windings into groups. I like to twist the wires in each group together, ie, two greens, two yellows, two blacks, red, red, and red/yellow. There are two mystery wires that are twisted together. Be sure they have continuity to each other but not to any other wires.

The two blacks are most likely the 120v primary winding. I would use a lamp limiter and apply 120v to the two blacks and just measure the voltages on all the other windings.

[dbishopbliss]

Here are the voltages:


Black - Black: 120.7V
Green - Green: 6.89V
Yellow - Yellow: 7.25V
Yellow - Yellow/Red: 3.55V
Red - Red: 672V
Red - Red/Yellow: 328V
Blue - White: 0.725V


Obviously the Black wires are the primaries. The Red wires are the High Voltage Secondaries with a center tap. Are both the Green and the Yellow wires for filaments? Is the Yellow voltage higher so it could be used for DC? Any idea what the Blue - White wires are for?


Finally, what would you build with this? I'm hoping for a Supro 1690T.

[thetragichero]

yellow is likely higher because it has more current capability. what is stamped into the bell covers? besides possibly shedding light if it's a specific production model, it'll be good for the next person looking up information on this transformer

[HotBluePlates]

Here are the voltages:

Blue - White: 0.725V

A millivolt-reading between these wires is probably a red herring.

Does the Blue wire have continuity to any other wire on the transformer?  Does the White wire have continuity to any other wire?

[dbishopbliss]

Does the Blue wire have continuity to any other wire on the transformer?  Does the White wire have continuity to any other wire?

The White and Blue wires only have continuity to each other and no other wires.


Aside from those wires which will probably get insulated and not used... any thoughts on what voltages I would expect to get under load and what I could use this for?