house 220v circuit & RPC

[Mstrofcnfsn]

can I run a 7.5hp RPC off of a household 220v 30AMP circuit in my garage?

Thanks

[Al_The_Man]

Yes.
Al.

[Mstrofcnfsn]

Just "yes"?

[Al_The_Man]

Actually it will also depend on how much load you are going to put on as well as the RPC?
If you were thinking of driving a =>5hp load, 50amps would have been a better choice.
Al.

[wildwestpat]

Yes the supply is adequate but the surge during run up will possibly exceed 30 amp. A 7.5 HP is a beast of a motor to run from a 220 volt single phase supply. What protective fusing has your garage supply? Are you going to be mighty unpopular if the supply voltage sags due to the load on startup / heavy cutting loads? Some TV sets and computers object of low voltage drops (brown outs). I have had experience of domestic strife due to lamps diming when using a 2 HP motor for wood turnning (capacitor start motor) with the workshop supply having a separate 30 amp fuse in the main house supply box. Suggest you might consider a motor with soft start electronics.

Regards

Pat

[Mstrofcnfsn]

Recently acquired (free?) a 20 year old Stenhoj all electric car lift for my garage. It is powered by a ABB 3hp 3ph 2.2kw motor.

This is what I need a converter for. I have found a company that makes RPC's using cast iron motors....almost seems to good to be true for the price/quality/service he is charging delivered ($521 for an 1800 rpm RPC). [Elimia Industrial...Ken]

According to Ken a 220v cb will be adequate. From other forums I am getting conflicting info.

Currently there is no box in my garage...I just ran 10 g wire from my dryer plug recpt. to my garage.

Please advise...THX

[Al_The_Man]

I am running a 7.5 RPC with a 2 hp spindle load, a 30a load can handle it, but you need a RPC that gets up to speed fast and efficiently otherwise you trip the breaker, once it is up to speed then a 2.2kw load should be fine, as this one should run up at the normal rate.
Al.

[wildwestpat]

If triping of the breaker becomes a problem check the class of breaker fitted as there are slow acting ones that will give a bit more tolerance to gutsy inrush currents but still protect against sustained over loading. Do get the advice of a qualified electrician if you need to go this route. In the UK the breakers are known as type 'C' OR take Al's advice and run up with a reduced load and hope the surge is short enough duration not to trip the breaker. I am assuming the 7.5 HP motor is for a mill or lathe and the hoist motor is a separate issue.

When replacing the hoist motor take care as the motor and brake may be combined in the same shell as part of the motor. Powering up the motor releases the brake and hoist can be driven up or down remove the power and the motor stops driving and the brake is automatically re-applied. The use of a brake may or may not be necessary depending upon the design of the drive mechanism, how worn it is and the lubrication as well as the loading. Take a lot of care as hoists are not only dangerous but also subject to health and safety regulation due to the potential for fatal accidents.

Regards

Pat