G76 AC supply: Relay, power cable?

[N1AEP]

Looking for a relay for Gonset G76 AC supply, or suggestions for a substitute relay.

Also need a source for multi conductor PS cable to connect to tcvr. Antique Radio Supply has a cable but it does not have enough conductors.

Thanks for any info.

[WQ9E]

Hi,

My G-76 is operated from a Drake AC-3 supply.  I used a standard power relay with an R/C network across the contacts to reduce arcing from switching the HV.  My power supply is fairly inconvenient to get to at the moment but try a .1 uf capacitor (high voltage rated, should be at least twice your DC voltage for safety) in series with a 47 ohm resistor across the set of contacts that switches HV and check for arcing.  I have had this in operation for over 5 years with no problems.

Rodger WQ9E

[WQ9E]

To correct a typo, that should be a 470 ohm instead of 47 ohm resistor.  This resistor limits the surge current during arc suppression and I think most formulas suggest a value in ohms equal to between 1/2 and the full DC volts appearing.  I was trying to type quickly this morning due to internet outages due to our lovely IL snow/ice/rain/gale force winds...

Rodger WQ9E

[N1AEP]

What would be a "standard power relay" that I could use for this?  The image in the manual shows some sort of enclosed relay which looks pretty substantial. I'm not sure just what type of replacement relay would be suitable.

Also, could someone suggest a source for multi conductor shielded cable to run from the pwr supply to the tcvr? 

tnx 73

[WQ9E]

Hi Joel,

I sent you an email response but it apparently did not make it.  The following is a copy of that text:

I ordered an Omron general purpose relay from Mouser (www.mouser.com).  I would suggest Mouser stock #653-LY2-AC12 which I believe is the same model I installed and has the correct 12 volt AC coil.  This is a DPDT relay and all you need is an SPST relay but there are not many relays with 12 volt AC coils. In any case, at $7.50 it is not very expensive.  Most relays are designed to safely switch 250 volts AC with a large safety margin and 250 volts AC is equal to over 400 volts at the peak of the sine wave. Omron claims a 2000 volt AC dielectric strength and I have had no problems with my relay.  You should use an arc suppressor across the relay contacts and the values I gave you earlier were off due to a typo, the resistor should be about 470 ohms and a .1 capacitor should be about right.  Mouser has 2000 volt rated capacitors available and a .1 @ 2000 volts DC rating is part # 5984-940C20P1K-F for $2.86  Mouser has no minimum and shipping is quick with reasonable shipping charges.

As for the multi-conductor cable, maybe something you will find at a hamfest.  Otherwise, you can get heatshrink tubing in long lengths and use this for the outer cover.  Just be sure that you use sufficiently heavy wire for the filament wires and wire with HV insulation for the higher voltage lines.

73, Rodger WQ9E