I have one VFD. I have two motors, for a belt grinder and a disk. I want to set up two switches, one to switch between motors, and one for forward/reverse the disk motor. Seems fairly straightforward.... leave the VFD hooked up as is, and divert the current coming out of the VFD to either machine. Second guessing myself on the switches.... I'm thinking that I can get two DPDT switches, the kind with three positions for on/off/on. One would be the power, essentially disk/off/grinder and the other would be for the disk, forward/off/reverse. I'm running 220v. Would a 20A rated switch be sufficient? Feedback or suggestions?
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Help with switches
- Thread starter Jason Fry
- Start date
I plan to use my vfd to control my 2 x72, my mill, and a disk. The only way I can figure out how to make it fool proof is to take the lead coming out of the vfd and wire in a twist lock plug. Then each machine will also have a pigtail with twist locks. No switches and nothing else to go wrong. Reverse is built in on my vfd.
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Salem Straub posted a thread a while back that showed how he did this. You may find it on his web pages. Jess
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The way thay rate switches, the HP ratings are lower than what the amps would be when using the motors
Pay attention to the HP ratings
You are not going find that switch in home depot
Try Mouser, digikey, electrosonics, some sort of electronics supplier
http://www.bladeforums.com/forums/showthread.php/718007-Three-motors-one-VFD
http://www.bladeforums.com/forums/s...good-way-to-design-multiple-grinders-on-1-VFD
The switch I would use to select motors would be triple pole, double throw.
The motor has 3 hots and a ground.
The reversal switch can be a single pole, double throw switch.
Use the fundtion of the vfd to reverse so you are only switching the jumpers inside
teco
KB
Which model VFD ?
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John, You mention a DPDT switch - that only switches 2 wires. Is this a 3ph VFD with 3 hot wires and a ground from VFD to motor? As the gentleman mentioned, a 4 leg twist lock plug is the simplest way to go. There really NEEDS to be a safety ground from VFD to motor making 4 wires total. Both motors are about same hp rating?
There are some 3 pole switches that would do what you wish, just as you described. Yes, 20A would be a BIG plenty for switches. You're not switching under load, but after motor is stopped with VFD controls.
Ken H>
There are some 3 pole switches that would do what you wish, just as you described. Yes, 20A would be a BIG plenty for switches. You're not switching under load, but after motor is stopped with VFD controls.
Ken H>
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http://www.bladeforums.com/forums/showthread.php/797438-Last-check-for-my-switch
Not sure if the count included this one.
Not sure if the count included this one.
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Yep, the count nailed that one. That's how I do it, I have six machines now on a switch bank coming from my TECO FM50. He's right, it's good to do a fwd/rev switch, plus maybe run/stop, or fwd/stop/rev, as a separate circuit coming form the remote ports on the vfd. Your manual should tell you how to do this. I went the extra mile and made a run/stop, fwd/rev, speed pot remote box and have it on a cable leash that can reach any machine.
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Jason, I got a really good deal on a bunch of Carlisle 3-pole double throw switches on Ebay. I thought I was buying three switches but, I was buying three packs of three switches. They are rated for 240v 10a. I just used one to set up my two disc grinders on one KBAC24D. If it'll work for you, I'll send you one.
Bob
Bob
Alright... I'm going to try Bob's 3 pole double throw switch to go between motors, and ordered the exact fw/rev switch that goes with the KB 27, even though the shipping was 13$ on a 20$ switch... grr. Either way, should be good to go. Now all I lack is ordering the second motor. Have the disk already.
Had to look this one back up, but I think I've got it... Need to get some wire and a box to put Bob's switch in. Crappie need catching, and I have orders that the customers are really wanting on time, but I have a three day weekend. Hopefully I can get the fish caught, blades ground and HT, and disk assembled before it's time to go back to work Monday.
another option is to use plugs and receptables, check with Brian Evans, I think he has this setup.
I see Sandeggo has mentioned this above
less convenient and less elegant, but perhaps easier all around and safer for the VFD.
this pic is from his setup
I see Sandeggo has mentioned this above
less convenient and less elegant, but perhaps easier all around and safer for the VFD.
this pic is from his setup
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I did that for a while... it works, but boy does it get old.
I was doing that recently with my single phase machines and one outlet, as well. It got tiresome so I built a multi-outlet board for them, off the one 50 amp breaker.
I was doing that recently with my single phase machines and one outlet, as well. It got tiresome so I built a multi-outlet board for them, off the one 50 amp breaker.