Omega Enlarger problem

[ic-racer]

So both the Chromegatrol and the standard power supply trip the GFI but not the circuit breaker, right? Do the two power supplies trip the GFI when the enlarger head is unplugged from the power supply?

[Matt Brown]

So both the Chromegatrol and the standard power supply trip the GFI but not the circuit breaker, right? Do the two power supplies trip the GFI when the enlarger head is unplugged from the power supply?

Nope, they have to be plugged into the enlarger for the GFI trip to occur.

[ic-racer]

Nope, they have to be plugged into the enlarger for the GFI trip to occur.

Ok. There is not much in the head to go wrong. Perhaps the fan is bad.

[tkamiya]

Are you able to inspect the connector, inside the connector, and the wire itself? Insulation can go bad.

[John Weinland]

I have that Omega too, and there may be something intrinsic to the Omega timer that could trip a GFI. Looking at the schematic, you can see that there is a voltage-buck/boost winding on the power transformer with a series capacitor that will charge and discharge along with the inductive buck/boost winding. (It's the winding that does not appear to be connected to anything else). The initial power-on surge-backsurge through that buck/boost winding could appear to the GFI like a partial short between the neutral and hot line-input wires. Try the enlarger with all its accessories on an outlet that is not GFI-protected. If it works flawlessly, without any apparent electrical problems, the Omega may 1) either not be compatible with GFI outlets or 2) you have a very sensitive (low-current-trip) GFI. An electrician may be able to help with GFI outlets with reduced trip-sensitivity. Good luck - and you may want to obtain a schematic diagram for troubleshooting.

[ic-racer]

Looking at the schematic, you can see that there is a voltage-buck/boost winding on the power transformer with a series capacitor .

Good thought, but that ferroresonant transformer is only in the Chromegatrol. The 'standard' supply has a 'standard' transformer (OP indicated that the 'standard' supply also tripped the GFI).

[paul ron]

Here is a source for the schematic and other manuals...

http://www.jollinger.com/photo/cam-c...s/manuals.html

Sounds like the head is tripping the GFI, either throwing a spike or a dead short. Check the head for shorts in the plug, the fan, the lamp.

And yes try it in a regular non-GFI outlet.

I hope you'll let us know how this turns out?

[michaelbsc]

Sounds like the head is tripping the GFI, either throwing a spike or a dead short. Check the head for shorts in the plug, the fan, the lamp.

And yes try it in a regular non-GFI outlet.

I hope you'll let us know how this turns out?

What causes a GFI to trip is an imbalance between the hot and neutral. The assumption being that power is flowing out but not returning through the proper route, and possibly through you.

Check if your neutral and ground are shorted in the head. Or if neutral is open in the head. These would allow the device to "work" on a regular outlet, but trip a GFI.

[tkamiya]

If the GFI only trips when the head is connected to the power supply, then I'd concentrate on closely inspecting all the cables, connections, and what's in the head. All it takes is damaged insulation, dense cobweb that got wet, dead bug across terminals, etc to cause 5mA or less of leakage. A dead short will trip regular circuit breaker. Tripping GFI is already indicating there IS a leakage somewhere. If you do connect it to non GFI outlet, please be careful. You already know there IS a problem....

Michael has a great idea. Yup, open return (white wire) will cause this condition too....