Toroid question

[amisdad]

I am using Brians V1 board. I just recieved the transformer for my first GC today. I have a few questions. The primaries are red, black, and yellow. I know that red and black go to the mains. What do I do with the yellow? Just terminate it closed so that it doesn't ever make contact with anything? Also, I have two blue secondaries and two green secondaries. How do I know which one will go to AC1N and AC1H as well as the AC2 side. I know that the two blue leads are a pair but do not know which one is hot. I know that my answer involves my multimeter. I did try to put a small voltage through the primaries and I got the same reading on each secondary lead. I have attached a picture for reference.

[BlackDog]

It really doesn't matter which way round the 2 wires of each secondary pair are connected. The output voltage is AC, and the rectifier dridge doesn't really care which way round things are connected on the input side.

Steve

Originally posted by amisdad
I am using Brians V1 board. I just recieved the transformer for my first GC today. I have a few questions. The primaries are red, black, and yellow. I know that red and black go to the mains. What do I do with the yellow? Just terminate it closed so that it doesn't ever make contact with anything? Also, I have two blue secondaries and two green secondaries. How do I know which one will go to AC1N and AC1H as well as the AC2 side. I know that the two blue leads are a pair but do not know which one is hot. I know that my answer involves my multimeter. I did try to put a small voltage through the primaries and I got the same reading on each secondary lead. I have attached a picture for reference.

[amisdad]

Boy do I feel smart!

[peranders]

Originally posted by BlackDog
It really doesn't matter which way round the 2 wires of each secondary pair are connected. The output voltage is AC, and the rectifier dridge doesn't really care which way round things are connected on the input side.

It does matter ONLY if you have _one_ rectifier bridge and want to create +- voltage.

This wasn't so unsmart question after all, but it's better to ask and feel studip than connect wrong and be

[Franz G]

You should check the yellow cable with an ohmmeter.

If it is connected to the primary side: then maybe 50% of the primary is for 117V and the full primary for 230V?

If it is not connected to any winding, then it is a shield, wich should be connected for safety reasons to the "earth" (the AC-ground eg. Box). I have never seen shields at torroids, up to now.

Franz

[amisdad]

The label states that the yellow lead is for 230V. I got this transformer on Ebay for a mere $25.00. It is 2x21V 400VA. Not a bad deal I think? It appears to be of great quality. I'll post the results of the transformer when I'm done with the amp. Thanks for all of your help!

[Franz G]

Then just isolate the yellow wire (and fix it).

You are on the happy side, with 117V: you can try the primaries without risking the tranny.

Here, with the 230V net, we must think before try, because trafos are not smokeable

Franz