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AssuredElectrical
AssuredElectrical, Master Electrician
Category: Electrical
Satisfied Customers: 4241
Experience:  Contractor-42+ Years in the ElectricalTrade
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What size beaker do I need for a Rockwell #83-651 230v mot

This answer was rated:

What size beaker do I need for a Rockwell #83-651 230v motor?

AssuredElectrical :

Welcome. My name is XXXXX XXXXX would be glad to assist.

AssuredElectrical :

I show that motor as :




  • Model 83-651

  • 3HP

  • 3450 RPM

  • 230V

  • 15.5A


Customer:

That is correct

AssuredElectrical :

So, you need to have a 20 amp breaker for feeding with #12 wire at a maximum distance of around 75 feet

AssuredElectrical :

That is a double pole 20 amp. 2 phases and ground wire to the motor. No neutral needed.

Customer:

Thank you. I'm glad I checked. I was told by someone that it needed a 30 amp with #10 wire.

AssuredElectrical :

Only 15 amps. It should start fine with a standard short distance.

Customer:

The distance is less than 25 feet.

AssuredElectrical :

You should be fine then

Customer:

May I ask about another motor?

AssuredElectrical :

ok

Customer:

I have an air compressor. Campbell Hausfeild Model VT619503AJ with a Doerr Emerson motor #LR22132. Does this need a 30 amp breaker?

AssuredElectrical :

do you have the nameplate information?

AssuredElectrical :

I will try to find it also

Customer:

yes

AssuredElectrical :

what is listed for the voltage and amperage?

Customer:

15 amps , 240 volts. The L.R. Amps = 93.

AssuredElectrical :

That is the same as the other unit

AssuredElectrical :

The LR is the Locked Rotor amps if the motor were to be locked down

AssuredElectrical :

Motors ten to pull around 6 times running for a brief second when starting

AssuredElectrical :

If the application is standard, a regular breaker will take care of the inrush. If it will be a very Hard Start case, then need to look at up sizing the breaker, which requires upsizing the wire also.

Customer:

what is a very Hard Start?

AssuredElectrical :

A motor that is under a a high load when starting.

AssuredElectrical :

Small compressors overcome quickly and normally not a problem unless you are trying to control a high pressure point in the tank. Then the motor has to overcome the pressure in the tank to start pumping.

AssuredElectrical :

If you set the switch at say, 80 psi and turn it off at 115 psi, then that is not too hard of a start.

AssuredElectrical :

If you are going to start it at 100 and control to 115, then that may require an upsize.

Customer:

I see... thank you.

AssuredElectrical :

I always do a test. Short cord to the breaker and run a test to verify the difficulty starting

AssuredElectrical :

As a compressor or pump gets old and wears, it too will cause a higher current

Customer:

I think I'll run #10 wire with a 30 amp breaker. The cost difference small. Much cheaper then if I need to upsize later.

AssuredElectrical :

That will provide a good overage safety point.

AssuredElectrical :

Most applications are not too severe on the start load. What happens, if there is a load at starting, it escalates the current drastically. Under normal on off type situations at low load, it isnt an issue.

Customer:

The fist motor is on a table saw. When cutting thick stock and the motor is under a heavier load, does that increase the current draw?

AssuredElectrical :

The starting is what you need to be aware of, so on a saw, it will come up to speed easily. The load is not higher when cutting, only if you jam the blade.

AssuredElectrical :

Table saws are easy starters

Customer:

Ok... then a 20 amp is fine.

AssuredElectrical :

should be great, circuit by itself though.

Customer:

Absolutly. Thanks again for your help

AssuredElectrical :

you are welcome, glad to assist

AssuredElectrical and other Electrical Specialists are ready to help you

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