Reversing KMG motor

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pike3e

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Sep 28, 2008
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I have the kmg with the 2hp leeson (red) motor sold by Rob. I know it will run in both directions because when the electrician wired it up it was going the wrong way the first time. Is it possible to wire in a switch to have the motor reverse and if so does anyone have a link??


Thanks

John
 
I have a 2hp motor on my KMG driven by a KBAC-27D vfd. I installed a reversing switch on the vfd, so I can run it backwards... BUT the KMG was not designed to track well when running backwards.

Erin
 
I have the 3 hp: motor and drive. (cat no. VS-VFD-3.0):
(220V only)
with this vfd and i also was wondering about using it in reverse with some knide of disc attacment ( 9" disc ). but i was worried i may srew up the vfd somehow. I would love to rig up an attacment. I cant be 100% sure but i think Rob said that it wouldnt be a good idea or something to that nature,. so i dont want to take any chances.--marekz
 

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I bought a Delta 220V vfd for my near future disc grinder. It has 3 phase output, on its manual it says "if you plug all the 3 output lines (from VFD to 3phase motor + there is a ground line of course) correctly the motor will run counterclockwise, and if 3 lines (coded U, V, W) plugged at different order (ground will stay the same) the motor will run clockwise by default. Of course it has online reverse command on the panel. But this will do the trick...

My electrician came up with a very cheap solution. There are 2 phase switches like this.
oc_65x656aqSaz.jpg

He says you he can wire 2 lines on that, and at "1" position it will run clockwise for example and at position "2" it will run counterclockwise...

Emre
 
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The VFD on my KMG reverses and the motor has no problem with that. The problem is that the KMG doesn't track correctly in reverse.
 
If you are going to go the inexpensive route and just wire in one of the reversing switches, I recommend that you leave the main power switch in place. Here's the logic:

The reversing switches usually have the [OFF] position in the middle, so a 'emergency stop' (aka OH CRAP!!!) may easily throw it into reverse. Also, the motion for stop is differnet depending on if you are running forward or reverse. There's nothing like fumbling for a switch when the brown stinky waste product hits the rotary ventilator.


Use the same on-off system you already do, and when the unit is off (and spun down) use the reversing switch to change direction, and that way you always have the same motions to turn the unit on and off.
 
I installed a reversing switch and you cannot go from forward to reverse without stoping the motor first. so if you are already going forward and turn it to reverse, the motor will continue to go forward....based off this grizzly industrial switch i picked up from them. Don't know about the other switches made by other companies.
 
marekz said:
I have the 3 hp: motor and drive. (cat no. VS-VFD-3.0):
(220V only)
with this vfd and i also was wondering about using it in reverse with some knide of disc attacment ( 9" disc ). but i was worried i may srew up the vfd somehow. I would love to rig up an attacment. I cant be 100% sure but i think Rob said that it wouldnt be a good idea or something to that nature,. so i dont want to take any chances.--marekz
Click to expand...



I'll be damned if i can find that thread, but there is a thread here somewhere where Rob? goes through wiring the VFD with a reversal switch.

You need a simple double pole double throw switch rated for the application ie 3 HP or larger
DPDT

09TOGGLE%20SWITCH%203A250V%205A125V%20%202T%206PIN%20NT$25-.jpg


What you are trying to do is simply reverse to of the output leads to the motor. Like pulling them off and swapping them.

13516d1114915520-forgot-how-wire-reverse-polarity-switch-reverse.gif


The inside of the motor cover plate should have some wiring info etched in it too.

CDH
(haven' figured out multiple quotes)
The reversing switches usually have the [OFF] position in the middle, so a 'emergency stop' (aka OH CRAP!!!) may easily throw it into reverse. .


There is a style of switch available that won't go directly from forward through off and to reverse. You are right , not commonly available in retail stores.
Possibly called "DPDT, three position, centre off"
 
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as far as tracking goes- i really wont need to worry about it if im rigging a disc. I figure if i had the correct size table i could have my kmg on one side and rigg up a disc set up on the other side and just switch the belt to the disc pulley and disengage the kmg pulley. Or i could have a double pulley and just take the 2x72 belt off.-but that would mean the disc would be in motion when using the kmg unless there was a way to engage and disengage the disc- at the disc. one flew over the cuckoos nest-marekz
 
My KMG doesn't seem to have a problem with tracking when run in reverse, although I never seem to run it that direction any more.

Mike L.
 
Hi John, Yes, that motor can be easily reversed with a drum rotary switch. This is the switch that will work with your 110090 single phase motor:

2X440.JPG


http://www.grainger.com/Grainger/items/2X440?Pid=search


They are a real buggar to figure out though as there are so many combinations.

But don't fear, I've already figured it out and somewhere I have a wiring diagram. If you go this route, let me know and I'l find that diagram.

Yes, the KMG doesn't track very well in reverse....but it will run backwards without trouble. This might be a good solution for sharpening with the belt running away from you....BUT be aware of the hazard of accidently running it at full speed and not realizing that it is going backwards when you start to hog on a new piece. "DANGER DANGER"



Here's the diagram: http://beaumontmetalworks.com/motors/rev-switch-diagram.jpg

-Rob
 
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