control transformer wiring

I want to connect a control transformer to my Ac unit. I need to connect it to 220 Volts AC. The one I have has 4 wires to connect to. White as common, black 115vac, blue 208vac, red 240 vac. how do I connect my wires to 220 volts?

YOU dont...hire someone

Ignac,

If it were me, I would connect the white and red wires to the 220 volts AC power, assuming that you have two other wires that you did not mention for the secondary 24 volts control power.

If it is the voltage levels that are confusing you, welcome to the club. Electric utility supply voltage is usually listed as the actual voltage, but many people mistakenly confuse this with the nameplate voltage on their household appliances. Equipment nameplates usually list the SMALLEST voltage at which the unit can be safely operated. Hence, the 240 volt lead on your transformer is talking about the same voltage as the "220 volts" that you assumed is your residential supply. Actually it is closer to 240 at most electric utilities around the country. I have measured some as high as 250 volts. I have not seen one running at 220 volts in about 40 years. If you don't believe this I challenge you to take a voltmeter and measure your voltage.

Control Transformer

Thanks Lancie1,

Your right. The voltage will be higher than 220V. I was confused with connecting the white (common) or the black (120v).

Thanks.

Is your insurance policy paid up?

You don't say where you are located. In Europe and most of the world outside the US the nominal voltage is 220 line to neutral and ground. In the US the nominal voltage is 220 single phase is line to line, and 110 line to neutral and ground.

I agree that if you aren't sure how this should be hooked up you should get assistance from someone with experience.

Tom Jenkins said:

In Europe and most of the world outside the US the nominal voltage is 220 line to neutral and ground.

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We won't 'split hairs' over this Tom, but Europe is 230v not 220v.

We, that is us Europeans, are all harmonised now!!

Apart from that I echo Ron's reply

Paul

Minor rant

This supply voltage/frequency thing is killing me. I wish we had a world standard but I reckon that would mean the US would have to convert and I dont see that happening any time soon.

What really kills me is the 220/230/240 thing...I get too confused on what should be what and where at times...especially since power companies may provide as high as 250 or as low as 210 for the above.

Same thing applies to 440/460/480...what is it really suppose to be? Depending on location etc you may get a meter reading of 495vac or as low as 420.
End rant

Technically I make sure I am aware of what supply power is "suppose" to be. In most cases there is a +/- 10% leeway for devices so the supply can vary.

ron we have the same problem up here to..

old school is 575 new school 600 utility provides anywhere from 570-620,

is it 110 or 120 likewise with 210,220 and 240.. The only constant we have is 208..nobody calls it anything else (asside from customers who call is 240v 3 phase) and the supply is pretty damn close to that..

is it 110 or 120 likewise with 210,220 and 240.. The only constant we have is 208..nobody calls it anything else (asside from customers who call is 240v 3 phase) and the supply is pretty damn close to that..

Click to expand...

You left out 115..lol you got it, thats what I was refering too.

Guys,

The voltage level question continues to confuse many people. Let me give you the benefit of 40 years of dealing with this question. Like I said earlier on the voltage level question, the confusion comes from the fact that for every voltage, there are TWO parameters. These are:

(1) The lowest voltage at which a power-USER device will operate safely;
(2) The voltage that the electric utility, transformer, or generator, will SUPPLY.

If you keep these two different voltage concepts in mind when you view any listing or nameplate, you will NOT ever be confused by this again.

For example, suppose you are looking at the nameplate on your air conditioner motor. It is a power user, so the voltage given will be the LOWEST level that it can operate at. Notice here that this motor nameplate voltage says NOTHING about what the LINE voltage will actually be. Because most peoples experience is only with user appliances, they mistakenly ASSSUME that this power-user nameplate is telling them the actual line voltage. Not true!

Now suppose you are looking at the nameplate on a transformer. This is a power SUPPLIER, and the voltages listed will be the real voltages, if you measure them with a voltmeter.

With the above in mind, you can see that all those different levels (220, 230, and 240) are really talking about the same thing, just looking at it from a different viewpoint.

Lancie1 said:

Guys,

Let me give you the benefit of 40 years of dealing with this question.....

Click to expand...

I hope I never get the chance to have 40 years expierance...

Mike, 40 years experience may be tough to get, but I still think it is better than the alternative... A bunch of my old buddies have dropped out of the race already.

To quote the immortal Freddy Mercury,

"who wants to live forever?"

I do!

Or at least until it is no fun anymore.

So let me clairify that...

I hope I never get the chance to have 40 years WORKING expierance...However I'm looking for at least 80 years expierance in the art of life.