Internal wiring of MHO relay

[Mbrooke]

I have a GE CEB MHO relay. Can anyone tell me why the transformer wiring for the zone 3 is different relative to the two others on the left? Or is just a print mistake?

https://files.engineering.com/getfi...5a7-4ed6-9b17-e93cd6e6ead9&file=MHO_relay.jpg

 

[davidbeach]

Drawing error? I’d expect both sides of the Z3 element to be symmetrical and the aren’t. There should be differences between Z3 and the others for the offset, but the two halves of Z3 should be the same.

 

[Mbrooke]

Thats what I'm thinking, but at the same wonder if there is an legitimate reason... how does Z3 achieve its offset anyways? That was my suspicion when I saw the different wring but it doesn't add up.

 

[marks1080]

*Sorry for the delay on this reply. I wanted to check some old manuals first.

Mbrooke,

Is your diagram from the manual or is it on a drawing you have? It is the exact same diagram in the CEB52A manual. I'm not sure I would assume it's wrong... Is it related to the zone 3 offset?

 

[marks1080]

GEC52A manual

 

[marks1080]

another GEC52A manual...

 

[Mbrooke]

Its ok- the schematic is directly out of the CEB52A manual. I am thinking it should match page 22 in your second link. The way its wired doesn't even seem possible to operate correctly- but for the life of me can't figure it out if it is indeed legit.

 

[marks1080]

Ya i tried to quickly analyse the circuit.. but realized I was mostly just guessing. My guess is the wiring is correct and it's what is pulling the zone 3 circle into quadrants 3 and 4. If you're able to bench test the relay you could probably play around with the wiring and see what the effects are.