Motor Reverse

[Mel Reed]

Hi, Can an electric 1hp motor be rewired to a switch of some kind so it will turn in either direction?How it this done?The motor is on a jet lathe.
Thanks for any help Mel:)

[Rod Sheridan]

Hi Mel, check the nameplate, manual or wiring diagram inside the motor terminal box for instructions on reversing the motor.

To reverse a single phase induction motor with a starting winding, the start winding connections are electrically reversed, usually by using a double pole, double throw switch.

Many motors cannot be reversed, because the starting winding connections are not accesible. These motors were meant for a definite purpose where reverse wouldn't be used. ( a saw or planer for example).

If the start winding leads are accesible, you will be able to add a switch to reverse the direction.

If you're using this on a lathe however, you may not be able to use all accesories such as a threaded faceplate or chuck adapter in reverse.

My lathe is reversible, and I find it very handy for turning the inside of bowls........Regards, Rod.

[James Jaragosky]

This can only be done with a D.C. motor. To achieve this with a A.C. motor you would need some type of transmission, as the motor will only turn in one direction.

[Bob Hamilton]

Hi, James:
Sorry, but that is flat out false. An AC motor will turn in whichever direction the initial "kick", which normally comes from the start windings, tells it to turn. A motor which has had the start windings burnt out will just sit and hum when you turn it on, but if you give the shaft a spin it will take off and run in whichever direction you spun it. I used that for years as a low tech reversible motor on my sharpening station with a grind stone on one end of the belt driven arbor and a buffing wheel on the other.

Take care
Bob

[James Jaragosky]

Well I stand corrected, but you need the proper type of motor. A standard 3 wire is not intended to run in reverse. That said, it would appear there is a work around, see the attached link. Good luck and be safe.
http://www.homemetalshopclub.org/news/sep01/sep01.html

[robert hainstock]

If the motor has a removable plate over the connection box, Look inside and if there are six wires, two power cord, plus four others; it can be reversed. I don"t remember the sequence any more, but I know it can be done. I am a retired USN vet and was a Navy electrician. Best of luck! :)
the green wire is ground and there for safety only.

[Steve Schlumpf]

Mel - I wired a light switch on my old craftsman lathe that allowed the motor to turn in reverse. As Bob stated - there should be a plate over the connection box on the motor. On the inside of the cover (on my motor) there was a small wiring diagram that pointed out which wires were for what. The switch I installed simply reversed the positions of the primary wires. If you have a schematic for the motor - post it and we should be able to figure out what your next step should be.

[Bill Fleming]

Attached (not - too big to upload - it is 2 meg - send me a private e-mail if you are interested and I will send on to you) is some info. that I found when thinking about the same thing. I decided not to move forward because my spindle didn't have have a groove for a safety set screw to keep attachments on the spindle.

Good Luck - Bill