220 Volt Question

Unless you are running single wires in conduit Romex does not come with two black wires even in four wire it's bare, black, white, and red sometimes the bare is green. In three phase and in 220v single phase no current flows in the neutral or in the ground. Residential wiring is a lot different from industrial due to the fact they use multiple single wires and pull them though conduit and they have the proper colors needed to do the job. Oh and my son is a Journeyman Electrican.

Todd
 
After a career in electricity, I think the advice from master53yoda and MICK1959 is the best. If you are not 100% sure of yourself, hire it done. After all, being professionally done adds to property value and desirability. When you do it, we all wonder.
 
Aside from all the things discussed so far, I DO NOT think the transformer in question will do the job safely anyway. This opens up another can of worms but...

This transformer converts US 120 volt power (120 volts to neutral) to European 240 volt power (240 volts to neutral). That will not work for a US type 240 volt tool, as it expects US type 240 volt power which is: (120 volts-Neutral-120 volts). The two 120 volt lines are out of phase by 180 degrees.

So this transformer will place 240 volts on a circuit in the machine that expects 120 volts, and will ground the other circuit (via the neutral) that should have 120 volts on it.

Dennis
 
Dave Smith said:
I'm not an electrician but I have done a lot of factory maintenance work for about 24 years--I do know the reason that you want 4 wires going to a 220v machine is just not to run the 220 motor--but to also supply a neutral wire for a 110 plug receptical or a simple thing like a light bulb--the ground wire is not to be used for these.--Dave----*your neutral and ground only are connected and meet in your main entrance panel ---not anywhere else--an electrical inspector explained that to me, and I haven't forgotten
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yes, esp. a sub panel needs 4 wire, and the ground and neutral are kept separate, never tied together. neutral buss bar is isolated from the metal box too.
 
mixdenny said:
Aside from all the things discussed so far, I DO NOT think the transformer in question will do the job safely anyway. This opens up another can of worms but...

This transformer converts US 120 volt power (120 volts to neutral) to European 240 volt power (240 volts to neutral). That will not work for a US type 240 volt tool, as it expects US type 240 volt power which is: (120 volts-Neutral-120 volts). The two 120 volt lines are out of phase by 180 degrees.

So this transformer will place 240 volts on a circuit in the machine that expects 120 volts, and will ground the other circuit (via the neutral) that should have 120 volts on it.

Dennis
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If it comes with a European outlet he should, of course, remove it and wire the secondary directly to his motor (or via an appropriate connector). The transformer itself would work ok, but it isn't the optimum solution to the problem.
 
mixdenny said:
Aside from all the things discussed so far, I DO NOT think the transformer in question will do the job safely anyway. This opens up another can of worms but...

This transformer converts US 120 volt power (120 volts to neutral) to European 240 volt power (240 volts to neutral). That will not work for a US type 240 volt tool, as it expects US type 240 volt power which is: (120 volts-Neutral-120 volts). The two 120 volt lines are out of phase by 180 degrees.

So this transformer will place 240 volts on a circuit in the machine that expects 120 volts, and will ground the other circuit (via the neutral) that should have 120 volts on it.

Dennis
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This is very informative. Thanks.
So is the US 240 volt essentially a two-phase circuit?
 
k1pyp said:
This is very informative. Thanks.
So is the US 240 volt essentially a two-phase circuit?
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No. The 240 coming into your house is single-phase. The secondary of the transformer out by the street is center tapped. The tap is the neutral and is grounded. Each hot leg thus gives 120 referred to the neutral or 240 referred to the other leg. Thus the two legs are 180 degrees out of phase, which is simply opposite polarity. Electricians often refer to the legs as phases, but this is not correct.

Two phase consists of two phases at 90 degrees. It is not used for power distribution.
 
John Hasler said:
No. The 240 coming into your house is single-phase. The secondary of the transformer out by the street is center tapped. The tap is the neutral and is grounded. Each hot leg thus gives 120 referred to the neutral or 240 referred to the other leg. Thus the two legs are 180 degrees out of phase, which is simply opposite polarity. Electricians often refer to the legs as phases, but this is not correct.

Two phase consists of two phases at 90 degrees. It is not used for power distribution.
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If I understand you correctly, it seems like the motor is experiencing the same 240 v either way so why can't you use a 120-240 converter?
Obviously I am not grasping the concept.
 
k1pyp said:
If I understand you correctly, it seems like the motor is experiencing the same 240 v either way so why can't you use a 120-240 converter?
Obviously I am not grasping the concept.
Click to expand...

You can if what you need is 240 single phase. Such a transformer may have a European-style outlet on it, though, with one pin grounded and the other at 240. If so you will want to rewire it. There probably won't be a center tap so you will have to either leave the secondary floating or run it European-style.

You could also rig an autotransformer from a 1:1 120V transformer, but if you knew how to do that you'd find it easier to just put in a subpanel.

Much better to just put in a subpanel.
 
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