Help with Equitech 1.5Q power conditioner

Oh, now I get it.

GFCI outlets do go bad, but it could also be equipment with a leaky capacitor to ground or a reactive load, which is most likely with bigger motors and amps.

If you find the problem is only your amp, I’d suspect swapping a GFCI won’t help.

Sometimes these trips happen intermittently, so hard to diagnose fully. Of course another alternative is to see if you can trigger any other outlet.  Maybe take the suspect piece of gear to your kitchen counter and see if you can trigger one of those outlets.

Maybe take the suspect piece of gear to your kitchen counter and see if you can trigger one of those outlets.

@erik_squires

FYI, the two 120V power systems are not configured the same. Though both, the OP’s, electrical service and the Equitech 1.5Q power conditioner are grounded split phase power systems.

The electrical service is a grounded power system.

120/240V. Two hot ungrounded conductors with a voltage of 240V nominal measured between the two Hot conductors.

The neutral, the grounded conductor. From either Hot, ungrounded conductor, to the neutral, grounded conductor, measures 120V nominal.

(Split Phase: Two 120V windings connected in series. The center point of the two windings connection is the neutral. The neutral is intentional connected to ground.)

When a 120V outlet is connected to the AC mains of the electrical service the Hot connects to the hot terminal on the outlet and the neutral connects to the neutral contact on the receptacle. EGC connects to the ground contact of the outlet.

(EGC is bonded to the neutral, grounded conductor, in the main electrical service equipment, electrical panel.)

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The Equitech 1.5Q power conditioner has an isolation transformer. Primary winding is 120V. Secondary winding is two 60V windings wired in series. The center point of the two windings connection is the neutral, the grounded conductor. The two outer ends of the two series windings are the HOT, ungrounded conductors. Difference of potential, voltage, measures 120Vac, Hot to Hot. From either Hot conductor to the neutral, grounded conductor, measures 60Vac.

The neutral is intentionally connected to the chassis of the Equitech 1.5Q, making it the Grounded Conductor... This connection to the chassis will also be where the EGCs conductors from the equipment ground contacts on all outlets will connect. (Note, the neutral from the Equitech 1.5Q is not used for power. It is used to configure the 120V output of the Equitech 1.5Q as grounded 60/120V power system.

As you can see the 120Vac power consists of two Hot ungrounded conductors. Not a Hot and neutral...

The two current carrying contacts on a 120V electrical outlet are fed with two Hot conductors. EGC contact on the outlet, from the neutral bonded to the chassis connection inside the Equitech 1.5Q .

From either Hot contact on the receptacle to the ground contact will measure 60Vac nominal.

The majority of audio equipment is designed to be fed from a grounded power system. A Hot ungrounded conductor an a neutral grounded conductor.

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A GFCI works by measuring the current that travels through the GFCI. Ideally it will measure the same on both sides, lines. If there is an imbalance of more than around 6ma the sensing device in the GFCI will cause the GFCI to trip. I believe that is what is happening with the OP’s Equitech 1.5Q.

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Hi @jea48  - Not my first time going through a balanced power system, though it is the first time I've known about GFCI on an example.  I read through your explanation, which is what I remember.  The part that I don't get is how a GFCI, connected to the secondary windings, tripping on a balanced power system would not also trip the kitchen outlet.

As you point out, the ground is not part of the GFCI sensing strategy in either case, but it's the imbalance between the current carrying conductors (which ground should not be except on a fault) which causes the trip.

@erik_squires

Say there is a small leakage ground fault in one of the OP’s equipment to chassis.

Say it is on the neutral wire inside of the equipment.

When the piece of faulted equipment is plugged into an outlet on the Equitech 1.5Q current will flow from the Hot ungrounded conductor to the chassis to the EGC. An imbalance of current will be detected between the two lines an cause the GFCI to trip. (Remember the equipment neutral is being fed with a HOT ungrounded conductor).

When the same piece of equipment is plugged into a GFCI, say in the kitchen, the small leakage ground fault will be connected to the neutral grounded conductor. There will not be a current imbalance in the hot and neutral conductors feeding the GFCI.

@jea48

When the same piece of equipment is plugged into a GFCI, say in the kitchen, the small leakage ground fault will be connected to the neutral grounded conductor.

I'm afraid I don't see this yet, but I also don't want to jack the OP's thread.  Let me go think on this for a while.