Converting a 4 wire extension cord to 3 wire

[Movin/on]

I'm going to be using a 10 gauge 4 wire RV cord to run a 10 amp 220 V motor and wonder what is the best way to eliminate the 4th wire (assuming it's the white neutral). I'm powering a 30 amp 220V switch for the motor.
Do I just eliminate/not use the slot in the extension cord and use only the ground thru to the motor?

Movin/on

 

[sberry]

One other question,,, is this motor rated to run on a 30 circuit? How heavy are the leafs on it, they would need to be 14 ahead of its own internal protection.

 

[wil]

You would need the neutral wire only if you plan on getting 120 volts out of the
working end of the cord. Else just the two hots and the ground wire to the frame.

 

[wyliesdiesels]

I'm going to be using a 10 gauge 4 wire RV cord to run a 10 amp 220 V motor and wonder what is the best way to eliminate the 4th wire (assuming it's the white neutral). I'm powering a 30 amp 220V switch for the motor.
Do I just eliminate/not use the slot in the extension cord and use only the ground thru to the motor?

Movin/on

What do you mean by eliminate?

If this is cordage there is no eliminating a conductor in the cord. Just don't hook it up.

BTW its 240v not 220v

You need to make sure the switch is rated for the same or greater HP as the motor. Since the motor is 10a this shouldnt be hard.

What is the HP rating on the motor?

 

[Movin/on]

The motor is 5.15 amps and 750 watts and the plate says 220V (Chinese manufacture) Yes I know 220 vs 240 volts. By eliminate I meant just not use or hook to the connection in the plug.

Movin/on

 

[sberry]

You may be limited to a 20A breaker.

 

[wyliesdiesels]

The motor is 5.15 amps and 750 watts and the plate says 220V (Chinese manufacture) Yes I know 220 vs 240 volts. By eliminate I meant just not use or hook to the connection in the plug.

Movin/on

Post a picture of the nameplate

Does this motor have integral overload protection?

BTW 10a 240v is NOT the same as 5a 240v. In your OP you said 10a and now youre saying 5.15a....

 

[bri_man57]

to answer the actual question, I use 4 wire on my machines that use VFDs to convert to 3 phase from single, and i simply just cut the 4th wire flush with the bundle and dont hook it up. easy peasy.

 

[wyliesdiesels]

to answer the actual question, I use 4 wire on my machines that use VFDs to convert to 3 phase from single, and i simply just cut the 4th wire flush with the bundle and dont hook it up. easy peasy.

So you dont ground your machines?

 

[bri_man57]

So you dont ground your machines?

Single phase has 3 wires off the outlet right? How go I hook 4 wires to a 3 prong 240v outlet? Lol. I'm basically using a 4 wire cord as a 3 wire cord

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[The Cobbler]

to answer the actual question, I use 4 wire on my machines that use VFDs to convert to 3 phase from single, and i simply just cut the 4th wire flush with the bundle and dont hook it up. easy peasy.

So you dont ground your machines?

Single phase has 3 wires off the outlet right? How go I hook 4 wires to a 3 prong 240v outlet? Lol. I'm basically using a 4 wire cord as a 3 wire cord

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Bri man, your post suggests you are using 3 phase power & cutting off one wire.

 

[Movin/on]

Well I posted before I checked the motor ID plate but took a guess that 10A would cover the wire capacity. I asked about this motor/pump back in Sept. 2019 and finally got the mounts made for the owner. He's not in a hurry and I've done quite a few projects for him in the meantime.
Just want to make sure the wiring is OK.
Wiley-- you posted to my prior question. Thanks.
Here is a picture of the plate

Richard >>> Movin/on.

 

[bri_man57]

Bri man, your post suggests you are using 3 phase power & cutting off one wire.

Ah, got ya. No, not doing that. What I was trying to say initially is i recently got a few 3 phase machines. I dont have 3 phase. So I use variable frequency drives to convert from single phase to 3 phase. Rather than get 3 wire cord, I just use the 4 wire cord that came with the machine, put a single phase 3 prong plug on it, and don't use the 4th wire. Which is similar to what the op is asking I believe. How to use a 4 wire in a 3 wire situation.

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[Bert_]

Why do you want to use #10 cord when #14 would do fine?

 

[wyliesdiesels]

Single phase has 3 wires off the outlet right? How go I hook 4 wires to a 3 prong 240v outlet? Lol. I'm basically using a 4 wire cord as a 3 wire cord

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yes single phase 240v is 3-wires: 2 ungrounded, 1 grounding conductor

Ah, got ya. No, not doing that. What I was trying to say initially is i recently got a few 3 phase machines. I dont have 3 phase. So I use variable frequency drives to convert from single phase to 3 phase. Rather than get 3 wire cord, I just use the 4 wire cord that came with the machine, put a single phase 3 prong plug on it, and don't use the 4th wire. Which is similar to what the op is asking I believe. How to use a 4 wire in a 3 wire situation.

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So lets clarify here. you're using 4-wire cord between the 3-phase machine and the VFD but are only hooking up 3-wires? If so, then thats incorrect because 3-phase has 3 ungrounded conductors and a grounding conductor. You need 4-wires NOT 3.

 

[wyliesdiesels]

Why do you want to use #10 cord when #14 would do fine?

yeah #10 is overkill

 

[bri_man57]

yes single phase 240v is 3-wires: 2 ungrounded, 1 grounding conductor







So lets clarify here. you're using 4-wire cord between the 3-phase machine and the VFD but are only hooking up 3-wires? If so, then thats incorrect because 3-phase has 3 ungrounded conductors and a grounding conductor. You need 4-wires NOT 3.

4 wire cord (but only using 3 of the wires) between the outlet and vfd, for the vfd input. I replaced a breaker box with the vfd and wired the 4 wire motors to the vfd. Sorry for the confusion.

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[sberry]

Yes, 14 and the ocpd could be 15,,, cord might even be 16?

 

[Movin/on]

The cord might be up to 100 ft. long and the proprietor was going to use 6 gauge so I talked him down to 10 gauge and the twist lock connectors are a good feature since the motor is on a cart and will be moved. Switch is there so the motor doesn't start when plugged in. 4 wire plugs for 6 Gauge here are around $16 and a 50 FT. cord (right now) is around $70.
Richard

 

[sberry]

This would run on 100 ft of 16. Nothing wrong with a little up size but it doesn't need 4 or 5 times. Why start with 4 conductor when it needs 3? Use a 20$ wire and 10$ or less recept. 5$ for a plug.

 

[Bert_]

Agree it would run fine on 100' of #16. The motor only draws 10a. Voltage drop is less of an issue on 240v than 120v

 

[sberry]

Yes, 14 for 100 ft of 120, at 240 16 unless it's plugged in to a circuit above 20A.