Help with Equitech 1.5Q power conditioner

@erik_squires I believe this is what @oddiofyl is referring to. The drawing is showing one cycle in time.

https://www.electronics-tutorials.ws/wp-content/uploads/2018/05/transformer-trans63.gif

The drawing shows a single phase, split phase, power transformer’s primary and split phase secondary winding.

For this discussion use 120V for the primary winding.

Secondary winding:

Center tap of the two windings is the neutral which will be intentionally earth grounded, bonded to the frame/chassis of the transformer enclosure, making it the Grounded Conductor. This Makes the secondary of the isolation transformer a Grounded Power System... (The neutral conductor will not be used for output power. All EGC conductors will connect to the grounded conductor.)

The two outer leads of the secondary are ungrounded, HOT, legs. From one HOT leg to the other HOT leg the voltage is 120Vac nominal. From either HOT leg to ground the voltage is 60Vac.

Neither of the two Hot legs are a neutral. They are both HOT ungrounded legs.

Again, the neutral is the center point of the two 60 volt windings that are connected in series. The neutral is connected to ground which makes the output a grounded power system.

Just because the NEMA 5-15R or 5-20R 120V receptacle has an Identified contact and connection terminal screw does not make the HOT ungrounded 60V to ground conductor a neutral conductor. It is not...

.

So, essentially the outlets on the back of the Equitech are wired the same way as old 240V appliances, the kind that had 3-wire cords. Correct? How does it handle floating-ground loads? I’m a bit confused

So, essentially the outlets on the back of the Equitech are wired the same way as old 240V appliances, the kind that had 3-wire cords. Correct?

That seems close, but the house N is not grounded through the Equitech. Or at least should not be. Ye olde (pre 1990s?) dryer DID bond N and ground internally to the dryer. There’s no reason to do that with a balanced conditioner... but I don’t speak for the manufacturers. Who knows what crazy things they do.

The secondary winding on these isolated devices is split. The center of the two coils is bonded to ground, so the outside ends of the 2 coils are each equal and opposite 60VAC.

And herein is a problem which the founder of Jensen transformers wrote about ages ago, that there’s still the possibility for a ground loop. Ooops.

Anyway, what floating ground load?

@devinplombier said:

o, essentially the outlets on the back of the Equitech are wired the same way as old 240V appliances,

No not all all.

Click on the Link below. Look at the secondary winding on the right hand side of the transformer.

https://www.electronics-tutorials.ws/wp-content/uploads/2018/05/transformer-trans63.gif

At the top of the drawing there is a lead that has IA + ___>______60V___

The bottom of the drawing there is a lead that has IB - ___>______60V___

(*Note: I added 60V to each lead.)

The 2 Hot leads, (60V + 60V = 120V between them), connect to the Hot and neutral terminals on a 120V GFCI duplex receptacle LINE. . (A GFCI duplex receptacle has LINE and LOAD connections).

It doesn’t matter which lead you connect on the neutral and Hot terminals on the GFCI duplex receptacle. (* Though ALL DUPLEX RECEPTACLES INSTALLED ON THE LOAD SIDE OF THE GFCI OUTLET SHOULD FOLLOW THROUGH THE SAME AS YOU WIRED THE GFCI OUTLET. That’s why two different colors of conductors should be used. Any two different colors other than WHITE or GRAY.

/ / /

Safety Equipment Ground that is created, wired, on the secondary side of the transformer.

Per NEC code the secondary winding of an isolation transformer shall be earth grounded. NEC code says the ground shall connect to the main grounding system (Grounding Electrode System) of the main electrical service entrance neutral conductor. (NEC allows the connection to be made at any point on the system ground.)

(Here Equitech may have violated the NEC. It depends on when the unit was made. For many years the NEC allowed the EGC at the wall outlet to be used for a grounding electrode conductor, ground. That was changed many years ago. The Equitech 1.5Q power conditioner uses the in-wall branch circuit wiring EGC, (Equipment Grounding Conductor), for the earth ground for the secondary of the transformer. The EGC ground pin on the IEC inlet connector connects, bonds, to the Equitech 1.5Q metal enclosure.

I’m getting there...

Back to the drawing of the transformer’s secondary winding.

https://www.electronics-tutorials.ws/wp-content/uploads/2018/05/transformer-trans63.gif

See the Blue line that connects to the center of the secondary winding? It has a - on top of it and a + on the bottom. This lead is the neutral Center Tap of two 60V windings.

For electrical safety the Secondary winding of an isolation transformer must be wired as a Grounded AC Power System. That is accomplished by connecting the winding center tapped neutral lead to earth ground and bonding the neutral to the metal enclosure housing the transformer. (The neutral lead from the center tap of secondary winding connects to the same point the EGC ground wire from the IEC inlet connector is bonded to the transformer metal enclosure. This is the same point that all EGCs for outlets will connect.

There is the safety equipment ground for all the power oulets.

How does it handle floating-ground loads?

There is not any floating ground loads.

One down side of a plug and play isolation transformer power system? IF the wall outlet, the unit plugs into, is not grounded...

.

So maybe I am conceptualizing this all wrong.

I guess in my mind I view electricity like water. It flows in through the hot pipe and out the neutral pipe, if you will, and the ground catches spills :)

Here we have 2 hots at 60V each flowing in through both the hot wire and what normally is the neutral wire. How does it flow out then? Can’t be through the ground wire. Is it then that the two hots are also neutrals? They just swap duties 60 times a second?