10HP, 240 volt 1ph motor needs switch

Status
Not open for further replies.
S

sw_ross

Senior Member
Location
NoDak
I have a rancher that has his hydraulic squeeze chute being operated by a 10HP motor. He has a 50-amp crows foot receptacle that he plugs it into, using that as his on/off switch 🙄.
He is concerned about it sparking when he unplugs it... Thinks maybe something is wrong with it....

Obviously he needs a better setup.

Is there a HP rated disconnect switch that would work for this setup or do I need to go to a contactor?
I think FLA was 60a if that sounds right?
Thanks
 
Sounds like it does not have any OL protection anyway. Sounds like you need a proper motor starter. Then you could just put a Hand/Off switch in the control circuit.
 
FLA for 10 HP, 230 volts would be 50 amps per nec table. So you would need wire for 62.5 amps. #6 copper would be fine. But you definitely need overload protection. Either a motor starter or a fused disconnect would work.
 
Thanks. I’m thinking I will mount a fused disconnect on the motor unit itself as an on-off switch.

he wants it to be portable because he moves the chute periodically from one ranch to another to work on cows. I’ll probably keep the 50-amp crows foot for portability purposes and just have him use the fused disconnect as the on/off.

Is there any major reason against doing this?

It’s pretty much standard practice on grain bin fans, up to 10HP, to use a disconnect switch as an on-off switch in this Part of the country. So it’d be similar to that.
 
sw_ross said:
Thanks. I’m thinking I will mount a fused disconnect on the motor unit itself as an on-off switch.

he wants it to be portable because he moves the chute periodically from one ranch to another to work on cows. I’ll probably keep the 50-amp crows foot for portability purposes and just have him use the fused disconnect as the on/off.

Is there any major reason against doing this?

It’s pretty much standard practice on grain bin fans, up to 10HP, to use a disconnect switch as an on-off switch in this Part of the country. So it’d be similar to that.
Click to expand...

Grain bin fans run for days once started.
If this squeeze chute gets repeatedly started/stopped I’d be concerned about the longevity of a disconnect switch. As others have recommended, you really should be using a motor starter.
 
Starter and estops make it a lot safer, I had a service I built for a syrup mill grinder, real old, and no safety features at all! Imagine a commercial wood chipper, except not with cutters, wide flat rollers that squeeze the juice out of sorghum canes. I put an estop where if someone got their hand in there, they could hit it with their knee.
 
ptonsparky said:
A new receptacle could be subject to GFCI requirements.
Click to expand...
We start the 2020 code January 1, so not required until then.
This is one of those times where I could see gfci protection being justified. The setup is located in a barn but there is potential for moisture/wetness being present.
 
sw_ross said:
We start the 2020 code January 1, so not required until then.
This is one of those times where I could see gfci protection being justified. The setup is located in a barn but there is potential for moisture/wetness being present.
Click to expand...
50 amp receptacles 150 volt or less to ground require GFCI protection in 2017 NEC. (other than dwellings anyway)
 
hillbilly1 said:
Starter and estops make it a lot safer, I had a service I built for a syrup mill grinder, real old, and no safety features at all! Imagine a commercial wood chipper, except not with cutters, wide flat rollers that squeeze the juice out of sorghum canes. I put an estop where if someone got their hand in there, they could hit it with their knee.
Click to expand...
Good idea. That way someone may hear you screaming in agony, and come help. o_O
 
retirede said:
Grain bin fans run for days once started.
If this squeeze chute gets repeatedly started/stopped I’d be concerned about the longevity of a disconnect switch. As others have recommended, you really should be using a motor starter.
Click to expand...
Grain Bin Fans?? This a hazardous Location?
 
kwired said:
50 amp receptacles 150 volt or less to ground require GFCI protection in 2017 NEC. (other than dwellings anyway)
Click to expand...
Oops! You’re right! I didn’t think about that. I’ll have to talk to the owner about that even though I didn’t install the circuit and am not altering it either.
 
First, I would make sure that the motor has its own internal OL protection, Many single phase motors do, you just need to be sure by looking for the words equating to "Thermally Protected" or even the abbreviation "TP" on the motor nameplate. If you don't see that clearly listed, you must assume it is not there and you will need external OL protection, i.e. a motor starter.

Magnetic motor starters have the advantage that if power fails while it is running, then comes back on again, it can be set up to not restart on its own, which might be a safety issue. In addition disconnect switches, although required by the NEC to be HP rated for this use, are not really motor starters. They are designed for approx. 6,000 operation under load, whereas a motor starter is designed for 1 million. Still, it's MUCH better than what he is doing now and 6,000 operations where it is operated a couple times per week is a long time, I'm just pointing out that using a disconnect as a motor starter has its drawbacks.
 
xformer said:
Grain Bin Fans?? This a hazardous Location?
Click to expand...
Typical on the farm bin normally is not. Something inside a plant maybe can be, usually because of other situations not the bin itself.

Most these have the fan outside the bin, drawing air through the bin to cool and/or control moisture inside the bin. Does not generally create a dusty situation to cause hazardous location for the fan or it's motor.
 
The last hydraulic pump I did for a squeeze chute, I used an Allen Bradley Nema starter in an enclosure with an off/on switch through the door. It takes a pretty beefy starter to operate 10hp single phase motor.

A pump panel may work well for you. They are typically three phase, but you could use one for single phase if you size it correctly and understand the wiring requirments to utilize it for single phase.
 
Status
Not open for further replies.
Top