Hey Guys
I'm in the process of building a 9" disc grinder with a 1 1/2 hp motor. I want the motor to be reversable and need to find out what type switch I need to reverse the motor and where to find one. I have wired several motors with switches and cords but have never tried a reversable setup. Any advice is appreciated.

Scott

Scott, I'm not 100% sure but pretty sure you just can't reverse a motor with just a switch. Think the motor has to be made to reverse. If you can do it with a switch let us know how. Did order the steel from Enco, really pleased with them. Just charge me a flat rate on shipping also. Ray

Thanks Ray
I've been browsing thru the Surplus Center catalog and located an item called a motor reversing swtch. It's a 2" by 4" black box with a lever on it that is supposed to work with up to a 1 1/2 hp motor. If thats all I need to wire in, the price is not bad but I don't want to turn a relatively inexpensive project into a monster (like most of my projects turn into).

Speaking of Enco, you just can't beat their prices or sevice. I've got a catalog in the shop, bedroom and library (toilet).

Scott

Hi Scott,
Maybe these schematics will help you figure out the wiring:

shop.emotorstore.com/esto...agrams.asp (http://shop.emotorstore.com/estore/TD_Schematic_Diagrams.asp)

They are linked to charts describing what has to be connected to what for cw/ccw rotation.
Regards,
Greg

If the motor is a reversable motor, you should be able to use a single pole/double throw switch to reverse it. Just wire one side of the switch to make it go one way and the other side of the switch to go the other. You will most likly have difficulty finding a switch like this at the local home depot. There are "Toggle" switches at Radio Shack that can handle up to 250V and quite a few amps so you will have to be sure the switch can handle it.

Most reversable motors will tell you in the schematic that to go one way wire to terminal "X" and to go the other way wire to terminal "Y". So you would wire terminal "X" to one side of the switch and terminal "Y" to the other side with your common in the middle. With some experimentation you will determine which terminal will go which way and you just mount your switch so that switching left goes counter clockwise and right goes clockwise with the center being off. Be sure to put the switch out of the way so you can't brush against it accidently.

Scott,
I've done it on a few machines. I use the rotary drum switches from Grainger. Call them on their 800 number and ask for tech support. These swithes work for single phase and 3 phase motors. Simply tell them what you want to do and they can fax you the hook-up schematic for the switch. They may ask for the motor maker, frame, model No...etc.

Good luck,
Rob

Does anyone have the phone number or website for the Surplus Center?
I am looking for a dc motor.

Larry Reese
Kenney, TX

Larry, Surplus Center, 1-800-488-3407, hope this helps.

I have done it in the past. If you want the switch to also be an on/off switch you need a double throw 8 pole switch. If it doesn't need the on/off capacity then a 6 pole/double throw will work (cross wire the outside four poles).

Gary

The rotory drum switch is the best way. That is what you find on most lathes and such to reverse them. The wiring diagram should be provided in the box. The motor should identify the wires inside.

Look on the Spec plate or in/under the connector cover box/plate. If it is reversible, it will show you which terminals to switch for reverse. That reversing switch box will ONLY work with a reversible motor.

3 phase is easy to reverse, just swap any 2 of the 3 hot wires (needs a BIG switch tho’)

PaulD

The shopmade 9" disk grinder I got from Johnny Stout is reversible (see the shop tour on my web site for pictures). In the power line to the motor, there is a box with two toggle switches; one for direction, and the other for the "ON/OFF" function. Works like a charm- just be careful that you don't hit the direction switch while the motor is running!

Thanks for all the help guys.

Scott