Weird Transformer Load Configuration

My best guess would be its part of a phase to phase buck or boost system for powering heating elements that use a different voltage than what the supply provides.

Or some goof thought he was an electrician when it was wired and some how has not managed to burn anything up or kill someone!

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GA

You are right. It is the same question for which he got no answers to satisfy him.

At least, if he really has this circuit at hand, he should reply to the questions asked about the voltages and currents and winding ratios.

I think the circuit has no real benefit as drawn. What ever the builder wanted to do could have been done better and easier if as drawn.

Probably, this is a Choke, using each winding (both equal...) in series with the attached load to cancel and filter the supply...? (i.e. L connected to both windings at the top, Load each in series with its winding, then to N. This will also balance the currents in each load (provided they are reasonably identical).

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What's the supply voltage (between L and N) and what's the voltage over the 2 loads?

One possibility may be "choke" coils. The impedance (though unbalanced) would reduce the current draw through the elements.

Strange enough, this configuration can mean a lot.

Telling us the nature and specifics of the loads and the transformer n1, n2 makes us aim better. Also be sure the transformer has 2 separate windings and is no auto- transformer.

is the transformer connected to a all electric heat elements inside the heater or to outer oil or gas jet burner as to reduce from higher ph~ to a lower secondary ph~

It's certainly unusual.

Does it work properly? What are the voltages at each node? Are the loads purely resistive? Do both load dissipate the same amount of heat?

I suspect it started out as an autotransformer used to adapt the loads to a different supply voltage.

Missing info:-

Phasing dots or other winding phasing information.

Working voltages, as measured.

Estimate of transformer kVA.

Thanks.

In this circuit the mid-point of the load is connected to the neutral. Neutral of the mains supply is usually connected to ground (earth) at the origin of the source and so the mid point of the load is automatically connected to the ground. This will result in loss of isolation of the load from the mains supply. If the mid point of the load was connected in series with a low value capacitor ( of the order of 500 picofarad) to the ground, it could have been interpreted as being a filter for high frquencies.

In case the circuit shown in your question is maintained, the phase and neutral wires should not be inverted.

This looks very close to the wiring i am using to boost low voltage for an inverter.

Having 98-99vac at home causes no or slow charging of batteries and fridge will not start. one of our engineers came up with something like that. It's 99vac + output of transformer 23vac giving me 122vac. This is un-regulated and dependent on line voltage but inverter switches at 132vac causing no damage to equipment.

BUT in the drawing submitted, One of the Loads will probably get a boost (depending on the direction of the windings), the other acting as a resistance in series...

This is important connection to allow current to flow, as power line connects to two terminals: L & N. This is interesting because both windings (primary and secondary) have the same current passing through.

The same Current passing in both Loads?

Not necessarily unless you can come with some explanation. The Top Load has 2 windings in series while the lower load(on drawing) has only one winding in series. We don't know the ratios nor the direction of the windings (Buck or Boost). Unless you do the test, there is nothing to say that there will be the same current in both loads.

Sorry for incomplete question. Each of the load is four heating element in series. This configuration is feed from a auto tap changer which change the taps as the resistance of load changes with time. The line voltage is changed from 2000 V to 300 V and current from 100 A to 3000 A. I have no details of the Transformer shown in the attached figure. We asked the vendor to design the system so it delivers EQUAL voltage and current to both the loads. And if one of the load becomes open it should not affect the Current and Voltage on the other load. I am sure there might be several different ways of doing it and I am not tying to redesign anything. Just trying to understand what is being provided. Here is an solution posted by jghrist on eng-tip.com BUT IF ONE OF THE LAODS R1 or R2 were to become open would it double the current trough the working load..

Now you are saying that there is an "auto tap changer" in your circuit(?) which makes your drawing wrong unless you are having this before the L point(!?).

My previous suggestion would balance the currents if the 2 loads are slightly not equal at any time by boosting or Bucking the voltages accross the windings...

If any of the loads goes OPEN, then the other will remain on its own and the current is limited by its resistance (normal current).

Yes the auto tap changer is feeding the circuit shown above (across L and N)

In the newly submitted diagram, the primary V1 winding and the secondary V2 winding are connected in series opposition through R2.

What does the transformer do. If for argument the ratio is 2:1 (with V1 at the input) will half of V1 always appear as V2 at the output ?

Therefore the currents must adjust to make this so.

What we need are some values to do some calculations.