Single phase transformers

[Klimon]

This really belongs in the "to stupid to ask-forum" but as there is no such thing I'll try here: can a single phase transformer be used as a power trafo, on a regular power net (which I suppose is 2-phase)?

I suspect the anwer is no....

Simon

[XEAGLEKEEPER]

Single phase transformers are used all the time..What eactly did you have in mind?

[Klimon]

Well, I always thought the electricity net was dual phase.....

Good to know that I can finally use those trafo's explicitly rated as 'monophase'

Simon

[richie00boy]

The mains grid is 3-phase.

I think you better tell us exactly what you are trying to do before you possibly start a fire or injure others

[Klimon]

I think you better tell us exactly what you are trying to do before you possibly start a fire or injure others

Don't worry, I've built several tube-amps without succeeding in killing my wife....

Seriously, I've got a transformer that is labeled 'single phase trafo' and was wondering if it's usable as power transformer for an amp, given my false presumption that 'normal' trafo's are dual phase (to suit the mains grid which I thought was also dual phase). The guy at the electronics store told me yesterday that mains grid IS single phase, so my transformer is just your-average transformer.

However, you say the mains grid is three phase

Practically; can I use my single phase trafo on the mains grid or can it only be used in specific industrial environments where mains grid is single phase?

Thanks --- Simon

[richie00boy]

Because you were vague with your original post you received confusing-to-you answers. The mains power grid is 3-phase, the power that comes into your home is 1-phase. You need 1-phase transformer to connect to the mains.

[Klimon]

That's a very clear-to-me answer.

Simon

[Speedskater]

In the US household service is often referred to as split phase. 3 wires into the house. 2 hot 120 Volt wires and a Neutral wire. A total of 240 Volts from one hot wire to the other. Commercial and Industrial users have three phase service. 3 hot wires (and maybe or maybe not a neutral) the phase between each hot wire is 120 degrees.
So maybe the transformer in question has a 2 wire primary rather than a 3 wire center tapped primary.

[Klimon]

So maybe the transformer in question has a 2 wire primary rather than a 3 wire center tapped primary.

It has, but I don't know if that has something to do with the denomination. Trafo's without centre-tap, atleast HV ones built or usable for tube-amps, are as common as center-tapped trafo's.

Simon

[Symon]

A three phase transformer will have 3 cores each with it's own primary and secondary windings.
http://www.3phasepower.org/3phasetransformers.htm

So a 3 phase transformer would look very different to a conventional single phase transformer. The fact it has 2 primary windings is usually an indication it can be setup for 120 or 240 Volt operation.