electrical gurus; 220 V motor on 2 wires????

[atch]

I have a 5.0 hp 220 V motor that has only two wires in the cord.

To make a 220 V supply do I connect to the 2 lugs on a 220 V breaker?

I can use the breaker for switching; how bad is that? (note: this will be only 'til I can get to town to buy a switch)

Here is a typical 220 V switch pic. Do the 2 wires from the motor go on one side (i.e. left) and the wires from the breaker go on the other side?

 

[mike93lx]

This isn't electrical guru territory. This is electrical basics.

240v in north America is two hots, on from each buss in the panel. A 5 hp motor should not have a cord

It may be prudent to hire an electrician and see what is done. There is more to this than figuring out where to plug a couple wires in

 

[u2slow]

You need a hp-rated switch, similar to this

https://www.amazon.ca/dp/B002MPPT3Y/?tag=atomicindus04-20

 

[atch]

hp-rated switch

When I clicked on the link it took me only to the Amazon home page (I tried it twice). When I searched for "hp-rated switch" on Amazon all sorts of stuff came up that I couldn't relate to. What should I put in the Amazon search box?

Thanx so far; how 'bout the breaker box question?

 

[dfiler2]

You don't want to use the breaker for a switch. Here is a magnetic switch made for a 5 hp electric motor, it depends some on what you are using the motor for.

https://www.amazon.com/dp/B006LASJPQ/?tag=atomicindus08-20

 

[atch]

So googling "220V hp rated switch" it came up with switches all the way from 14 bux at HD to a Hubbel at $155.

I am still unsuccessful searching Amazon.

What am I really looking for? i.e., specs on or description of the switch.

 

[atch]

Oops; dfiler2 and I were typing at the same time.

Still; what about the breaker box connection?

 

[u2slow]

When I clicked on the link it took me only to the Amazon home page (I tried it twice). When I searched for "hp-rated switch" on Amazon all sorts of stuff came up that I couldn't relate to. What should I put in the Amazon search box?

Thanx so far; how 'bout the breaker box question?

Weird. The product in the link is a Leviton MS303-DS

As for the breaker, use a 2-pole breaker. Typically the black wire on one terminal, and red wire on the other.

 

[atch]

b-t-w; fwiw; this thing will never have much of a load on it. It's the only "extra" motor I had laying around. I'm building a rotating tumbler to clean rusty bolts and such. I doubt it will ever have as much of a load as a drill press or lathe.

 

[atch]

Weird. The product in the link is a Leviton MS303-DS

As for the breaker, use a 2-pole breaker. Typically the black wire on one terminal, and red wire on the other.

Thanx. Searching Amazon for Leviton MS303-DS gave me results.

The breaker answer is what I expected but wanted confirmation from someone more experienced/smarter than me.

 

[beemerphile]

b-t-w; fwiw; this thing will never have much of a load on it. It's the only "extra" motor I had laying around. I'm building a rotating tumbler to clean rusty bolts and such. I doubt it will ever have as much of a load as a drill press or lathe.

It will be the inrush and not the running load that welds the switch contacts. You don't just need a HP rated switch, you need a 5 HP rated switch.

 

[Bondo]

Here is a typical 220 V switch pic.

Ayuh,.... That switch says 120v, right on it,.......

Regardless the load, that motor wire a 2 conductor cord is not properly wired for 220v operation,....

 

[atch]

Ayuh,.... That switch says 120v, right on it,.......

Regardless the load, that motor wire a 2 conductor cord is not properly wired for 220v operation,....

Well; sorry about the pic. It's just one that came up when I googled 220 V switch. Your (probably much younger) eyes caught the writing. I can't even read it.

As for the properly wired message it's apparently the original wiring on the motor. I can't guarantee that though. I'll get into the connection box on the motor and see what it looks like. There usually is a diagram on the inside of the cover.

 

[Bondo]

Ayuh,..... just left of the toggle, 20a 120v,....

 

[atch]

Two pix that lead me to believe that it is wired correctly and that this is the original cord. That being said I'm not here to participate in an argument about this. All I want to do is hook it up and make it run.

 

[manwithtools]

It needs a 3rd wire for the equipment ground. That's required to make it safe. Read the red print on the bottom of the motor label - "INSTALL AND GROUND PER APPLICABLE ELECTRICAL CODES" somewhere in the electrical connection box is a stud or screw that connects the motor frame to the ground wire.

 

[PoorUB]

Yes, you need a double breaker, one wire to each side, plus a ground wire, so a 2 wire plus ground cord.
Also, that is one of those wannabe 5 HP motors. It really isn't 5 HP, more like 3 HP. It is rated like the 7 HP shop vacs that will run on a 12o V, 15 amp outlet. Magical HP.

 

[u2slow]

Two pix that lead me to believe that it is wired correctly and that this is the original cord. That being said I'm not here to participate in an argument about this. All I want to do is hook it up and make it run.

My compressor is rated SPL and 15A @ 240v also. It uses a factory 6-20P cord. It is about 3hp.

Does your pressure switch not have a manual on/off toggle?

 

[manwithtools]

It's not on a compressor any more, he's using to run a fancy rock tumbler, err bolt tumbler...

 

[theoldwizard1]

Yes, you need a double breaker, one wire to each side, plus a ground wire, so a 2 wire plus ground cord.
Also, that is one of those wannabe 5 HP motors. It really isn't 5 HP, more like 3 HP. It is rated like the 7 HP shop vacs that will run on a 12o V, 15 amp outlet. Magical HP.

No disagreement, but what would an inspector say ?

Some bad part numbers above ! You want a motor rated, 2 pole, single phase switch, like a Leviton MS302-DS. It is rated for 5hp on a 240V circuit.

 

[AA7483]

You could also install a 2 pole contactor in a box rated for the amperage of the motor and use a standard switch to provide coil voltage. Thats what I did with my air compressor.

 

[KenC]

Ayuh,.... That switch says 120v, right on it,.......

Regardless the load, that motor wire a 2 conductor cord is not properly wired for 220v operation,....

Actually it says 120-277v on my monitor. Never have I seen a 2 pole single throw 120v only switch.

Agreed on a 2 conductor cord being improper for a lot of reasons. Plug connected 5hp, no ground etc.

 

[kbs2244]

Ratings aside

Doesn’t he want to switch the 2 hots and have a third wire in the cord that is wired from the nutral in the supply box to the frame of the motor?

Or, if the motor has a nutral lug in it's connection box, the third wire goes nutral to nutral and a forth goes from the supply ground to the motor frame?

 

[u2slow]

Some bad part numbers above ! You want a motor rated, 2 pole, single phase switch, like a Leviton MS302-DS. It is rated for 5hp on a 240V circuit.

Often at supply houses the 2pole isn't stocked, and the 3-pole can be substituted with one set of terminal positions going unused. That's been acceptable to my AHJ in the past.

 

[larry_g]

I think that a few here are failing to realise that this motor is most likely from a dimestore compressor where the ground was provided at the power input to the pressure switch and the whole frame of the compressor and the motor was considered grounded at that one point. Not the best grounding situation but legal. Now that the motor is removed from the grounded frame of the machine you have a new problem of how to ground the motor frame.

lg
no neat sig line

 

[KenC]

Ratings aside

Doesn’t he want to switch the 2 hots and have a third wire in the cord that is wired from the nutral in the supply box to the frame of the motor?

Or, if the motor has a nutral lug in it's connection box, the third wire goes nutral to nutral and a forth goes from the supply ground to the motor frame?

Safety ground, bare or green, not white neutral. Should be motor to branch circuit connection.

 

[Innovate1]

This isn't electrical guru territory. This is electrical basics.

240v in north America is two hots, on from each buss in the panel. A 5 hp motor should not have a cord

It may be prudent to hire an electrician and see what is done. There is more to this than figuring out where to plug a couple wires in

Small detail but it's bus not buss.

 

[PCustoms]

Often at supply houses the 2pole isn't stocked, and the 3-pole can be substituted with one set of terminal positions going unused. That's been acceptable to my AHJ in the past.

Got an example of a 3 pole switch that you are referencing?

 

[Norcal]

As long as it's not a disconnect, a single pole switch can be used for a 240V application, I never do it but it is code compliant, but the OP is failing reading comprehension 101, the motor is a 230V motor not 220V.

 

[beemerphile]

As long as it's not a disconnect, a single pole switch can be used for a 240V application, I never do it but it is code compliant, but the OP is failing reading comprehension 101, the motor is a 230V motor not 220V.

The only place I do it is for a thermostat on a 240V heater (which is fed from a 2-pole breaker).

 

[wyliesdiesels]

You could also install a 2 pole contactor in a box rated for the amperage of the motor and use a standard switch to provide coil voltage. Thats what I did with my air compressor.

The contactor needs to be rated for the HP rating of the motor not the amperage.

You only use the amperage rating when sizing a contactor for resistive loads like a heater

 

[u2slow]

Got an example of a 3 pole switch that you are referencing?

It is linked in my earlier post. Screenshot of it....

 

[u2slow]

The contactor needs to be rated for the HP rating of the motor not the amperage.

His motor is marked "5 . SPL"... not sure what is intended by that. Amperage would be higher than 15A for actual 5hp.

 

[beemerphile]

His motor is marked "5 . SPL"... not sure what is intended by that. Amperage would be higher than 15A for actual 5hp.

It is intended to deceive. SPL is the instantaneous peak horsepower, which is essentially the starting surge.

 

[rlitman]

It's not on a compressor any more, he's using to run a fancy rock tumbler, err bolt tumbler...

Sure, but the SPL rating is the giveaway that the motor was originally mated to some piece of equipment, rather than a general purpose motor, and this one was clearly part of a compressor, because you don't tend to find SPL ratings on much other than compressors or pool pumps. Larry_g got the grounding answer correct. But a 2-pole motor for a tumbler? 3450 RPM is going to need a lot of reduction.

 

[manwithtools]

Sure, but the SPL rating is the giveaway that the motor was originally mated to some piece of equipment, rather than a general purpose motor, and this one was clearly part of a compressor, because you don't tend to find SPL ratings on much other than compressors or pool pumps. Larry_g got the grounding answer correct. But a 2-pole motor for a tumbler? 3450 RPM is going to need a lot of reduction.

Obviously it's originally from a compressor, that does not change the requirement for properly grounding the motor. The motor manufacture clearly points that out on the rating tag. It does not mater how it was originally grounded, it needs an equipment grounding conductor now in the OP's use case. Plenty of places to attach one on that motor.

 

[theoldwizard1]

Often at supply houses the 2pole isn't stocked, and the 3-pole can be substituted with one set of terminal positions going unused. That's been acceptable to my AHJ in the past.

About $19 vs $35 on Amazon.

 

[theoldwizard1]

The contactor needs to be rated for the HP rating of the motor not the amperage.

Leviton MS302 and MS303 are 5 HP motor rated when used at 240V.

 

[atch]

Thank you one and all. I've learned some things through this thread.

So after reading all of this I went to my "old motor stash", found a 1725 rpm 1 hp 120V (115V???) motor that's still more horsepower than I need, and am using it. With all of the reduction I'm incorporating it's going to work just fine. It's (temporarily) mocked up and running now but will get more work to complete it.

If anyone wants the motor I posted just drop by Columbia, MO, and you can have it. I'll never jump through all of the hoops mentioned herein in order to be able to use it.

I thought of making an apology for wasting all of your time. However, perhaps someone out there can/will use the information herein and stay alive or not burn his/her building down. For that I thank you for posting the information.

 

[AA7483]

The contactor needs to be rated for the HP rating of the motor not the amperage.

You only use the amperage rating when sizing a contactor for resistive loads like a heater

Good point. I think I'm well covered with the 40 amp contactor I had on the truck, haha.