Coil Wiring

[beermaker]

I have an 8" coil from my old Excal 800 that I want to wire to one of my other Excals. I use the 4 pin Souriau connectors to swap between coils. The problem is the 8" coil is 5 wires (extra common) and the newer machines are 4 wires. Is there a way to wire the 5 wire coil to a 4 wire machine? I have connected the two commons together with no luck and I have tried using only one common with no luck. It seems I need the 5th wire from the board to make this work. Before I scrap the 8" coil I wanted to see if anyone had any ideas? Attached are the current pin connections.

Thanks for your help!

 

[JohninNC]

The fifth wire is probably unused. Take an ohm meter and measure the resistance between the pins on a coil that has a 4 pin plug. What you will find is that 2 pins go to the 'send' coil and 2 pins go to the 'receive' coil. The send coil will be low, maybe 4 to 20 ohms. The receive coil will be higher, maybe 40 to 100 ohms..... Now measure the wires for the old coil. You should find 2 pairs that match fairly close. The other wire is likely unused. White's machines didi something similar. They have a 5 pin plug, but some coil cables have 5 wires and some 4 wires. The fifth wire is unused. Hope this helps.

 

[beermaker]

Thanks John, your Ohms test did the trick. It turns out that I had crossed up the wires. I had labeled the orange wire as common and the green wire as receive when they are actually reversed. Without the ohms test I wouldn't have picked up the error. I should have tested the wires in the first place instead of taking the web diagram at face value. Your also correct that the extra common wire blue or green wasn't needed.

Thanks gain for your help!

 

[JimGilmore]

Ok, I am confused here.....what is common in the pin call out reffering to ?

 

[beermaker]

Jim, What I refer to as a common wire I believe is a ground wire. There are 2 transmit wires(black and red), a common or ground and a receive wire. Depending on which generation of Excal you have the common and receive wires may be different colors.

Here are the wire colors of my coil wires: The common wires on my five wire 8" standard excal coil are green and blue and the receive wire is orange. On my four wire 10" standard excal coil the common wire is yellow and the receive wire is white. On my WOT coil the white is common and the orange is receive. It took me a while to get these sorted out for my connector pins. I use quick connectors to swap out coils on my machines (I use the Souriau connectors which I like better than the Bulgins) so it took a while to get all the wire colors sorted out..