MGunnerM203

Just bought an old Rockwell 8 inch jointer that is powered by a 3 Phase motor. I need to repower this for home use- 1 Ph 220 volt.
I am looking at new/used 1.5 and 2 HP electric motors to replace the 3 Ph monster. Since there is no 3 PH power source available, I cant tell if the present motor is a 3450 RPM model or not - No motor tags/info. Should I buy a 1750 RPM motor or a 3450 RPM motor since I am replacing the motor anyway ? Can I use the old 3 PH on/off motor control on the new 220 V motor ? What else should I look out for as far a potential problems ? Thanks, MG.

TomD

I can't help with the RPM, but lets talk about the control. Is the control a simple on off switch or does it have a relay and are there any heaters for overload protection? There are different types of switches and some have motor protection. The heaters would have to be changed to match the amperage of the new motor. This would also be true of a relay with motor protection. If there is a relay, coil voltage is a definite consideration. 208v 3 phase is pretty common. The relay will probably work at 230 but, there is a possibility of burning out the coil. You'll end up with a spare contact and this is not a problem. If you buy a 3450 motor and it spins like crazy, can you reduce the sheave size? Or is there just a tiny one on there now?

Tom

joasis

See if you can locate the machine specifications online....or if all else fails, call Delta. The switch can be used since it will have 2 lines in the switch, and you must "open" both sides of 220 single phase to stop the motor. This is all assuming you don't have a magnetic starter. You could also look for an electric motor repair shop.....they might have a used motor of the same frame (mounting and shaft dia./height), and can very likely check out the motor control and set you up.

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Keithprice

I also have found a used reconditioned Rockwell 8 inch. It also has a three phase motor. I am interested in your final solution and am also curious about how much yours cost you and was it in good shape or did it require a lot of work.
Thanks in advance
Keith

Handyman

For information on older power shop tool try www.owwm.com All they do are old shop tools. Tuns of information there.

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woodnthings

Generally speaking a 1750 rpm motor will have a pully around 3" or 4"in dia and a 3450 rpm will have a smaller one. Maybe someone will have the specs either on line off this site or a helpful person from here will have them. You need to determine the desired rpm speed of the cutter head. For example 3" pulleys on both the cutter head and the motor will result in what ever speed the motor is. A 3" pully on the cutter head and a 1 1/2" pulley on the moter will result in the cutterhead turning 1/2 the rpm of the motor and so on. I don't think the rpm of the motor is as critical as the pulley sizes you end up using. A quick check of my Grizzly cat. shows a cutter head rpm of 5350 for an 8' jointer with 4 knives resulting in 21,400 cuts per min. model G0490 As they say...go figure! Good Luck, Bill

mwhafner

Why not buy a small phase converter? It would be probably be about the same price as a new motor.

MGunnerM203

Keith, I repowered my Jointer by buying a 1.5 HP motor on ebay which was selling locally(picked it up -no freight) for 50 bucks. I was able to use the 3PH switch as described by one of the posters here. Installed new pully to fit motor shaft. Works fine on 220 v . almost like new.

MGunnerM203 (Terry )

johnv51

I would spring for a magnetic switch for the 220vac motor. They are fail-safe designed. That is if they fail there is no power to the motor.

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BobbyfromHouston

Have you considered a new Grizzly motor? You can get any size you want especially from 1 1/2 hp to 3 hp , 220volts single phase. I purchased a 3hp Grizzly motor for my Delta saw and it works wonderfully.