question Help with Seddon Atkinson Voltage Dropper please

[N.O.S.]

I've just bought a couple of ex army Seddon Atkinson 24 to 12V, 10 amp voltage droppers, but haven't a clue as to the wiring code. :blush:

 

The 4 wires must be 24V + / 24V - / 12V + / 12V -, but which is which?

Wires are Black/white, black, yellow/white, yellow. The yellow/white wire has a big 'thingy' in line - could be a diode or something?

 

There is continuity between the black and black/white, so they could be either the 24v or 12v circuit pair - or they may both be earth :laugh: ,and there is just a short 'bleep from the continuity meter between yellow and yellow/white (must be the thingy creating open circuit when the wires are connected). I can't read resistance at the moment - meter trouble.

 

If anyone has a Seddon Atkinson wiring diagram (I'd guess the 6x4 tractor unit?), could you help? Or if you know what the thing is in the yellow wire maybe? Or any other bright ideas, other than suggesting I should have spent my money on chocolate instead?

 

[johnhughes]

i don't know the wiring layout for your dropper but i do know you must fuse it and it must be switched on the 24v side as it consumes power at all times even if there is no 12v load.

 

 

j

[radiomike7]

The yellow 'thingy' is most likely to be a choke, a coil of wire wrapped on a ferrite core to block AC while passing DC. The only other device it may be is a wire wound resistor as a simple 24/12v dropper for maintaining the radio memory when the main dropper feed is switched off, a system used on T45 Roadtrain where the yellow radio feed was purely for memory.

 

Do you have an Iveco dealer locally, they should still have info on SA products?

[Lauren Child]

Are the silver things on the other side terminals?

[N.O.S.]

Erm, erm - no, they're nuts which hold the cover on. :blush: I just assumed it was a sealed unit :blush:

 

Looks like the two blacks are definitely earths - but difficult to say which yellow is which.

However I could try 12v on each in turn and see what comes out of the other one :idea:

 

Thanks for your technical input, Lauren! Very politely done! :blush:

 

Edited April 24, 2012 by N.O.S.

[poppypiesdad]

is the yellow blob not an waterproof inline fuse holder , try pulling it apart , carefully

 

jamie

[N.O.S.]

Oh for crying out loud - I could have sworn it was a sealed unit! :blush: I haven't seen one that shape before. Thanks. :blush:

[P Marriott]

Hi Tony

 

Yes the yellow blob is a fuse holder, most likely the 24 volt supply, smaller conductor. Other yellow would be 12v output. Lower the voltage higher the current, therefore larger conductor, for a given power as I am sure you know.

 

Good luck

 

Red to black and blue too bits as we used to say when we encountered problems!!