Help with single phase to 3 phase

[Ernie Hobbs]

Hi everyone. I was hoping to ask this group for some help with a restoration of an old dust collector. I have a late 80s Grizzly Dust Collector (G1030) that has a 3HP, 3 phase motor, not original, that I'd like to restore and put back into service. I have 220 v single phase service. I'm also planning to put the dust collector in the room next to my shop, so I'll need to install a remote or hard-wired switch in my shop (15 to 20 feet away). I'll run 4" or 6" (haven't decided yet) duct work to the machines in my shop.

I have an old Crouch edge sander that I restored last year and was able to use a VFD to convert 3 phase to single phase. https://www.amazon.com/gp/product/B07BK ... UTF8&psc=1
That works great for the sander, but the only issue is that the switch on the sander has to stay on all the time and I use the VFD start/run button to turn it on. No big deal.

I was hoping to use something similar (higher HP, of course), but I am worried that the remote switch wouldn't work, as I assume the switch would be between the VFD and the machine. Can someone tell me how this setup would work? Maybe it is a setting on the VFD that I am not aware of. I know there are VFD remotes, but I expect that the cost would get high enough that it would be better just to swap out the motor to a single phase. Grizzly has a replacement motor for $391. At that price point, the cost of doing the restoration vs. buying a new one begins to not make sense.

Any advice would be much appreciated. Thanks!

[andy bessette]

...Grizzly has a replacement motor for $391... Thanks!

Everything else is used. Why spend on a new motor, when you can replace it with a used one for much less?

[andrew whicker]

I agree. 400 for a 220v motor seems reasonable. You could go ebay and get cheaper.

3 hp isn't a lot of amperage draw and you're probably not gaining anything with the smoother running three phase on a dust collector.

[Bill Space]

Or just buy a cheap VFD off ebay or amazon, or wherever, and convert your 220 vac single phase to 3 phase at each device you have.

Simple, easy, and many people do it with great success. Cheapest way also these days it seems...this is what I would do. You don't use the variable frequency aspect, just set the output to 60 HZ and forget it....might have a soft start option that could be beneficial.

[Bill Howatt]

If your initial post referred to putting a switch between the VFD output and the motor, do not do it!
You can control the VFD run/no-run condition with a regular switch and these often are a low voltage (24V or less) to there is no wiring concerns for the control function. You can probably find a wireless remote relay if you don't want a wire.

[ray grundhoefer]

Get a teco vfd from factorymation. Then get a cheap christmas tree light remote that switches 120v.Use that to control a relay with a 120v coil to turn the vfd control circuit on and off. Did that for mine and it works great.

[Bill Dufour]

The VFD will have a a set of control terminals. You will have to enable them. Then wire an on/off switch connecting those terminals together to turn the vfd on and off. The on/off switch could be a 120 volt coil relay controlled by a remote Christmas light system.
Bill D

[Robert Hayward]

My one and only VFD has the control terminals. Once the terminals were enabled and a separate set of low voltage wires were run to the machine I use the machine original buttons to turn on, turn off and lock the buttons. I have an Oliver 4240 with a three button control box. Off, On and Lock.

[Ernie Hobbs]

I think my problem with the VFD and my Crouch sander is that I wired the switch between the VFD and the sander, which is incorrect. I probably should go back and fix it, though it isn't a big problem the way it is. I just keep the switch on and operate the sander from the VFD, which is right above the machine.

An update on the progress of the restoration: I have taken apart the dust collector and painted the parts Grizzly green (or the closest I can get with Rust Oleum). I have ordered a VFD, new gasket material and a remote switch, so when they come in, I'll reassemble the DC and see if I can get it running. While I wait for Amazon, tomorrow I'll run the 220 v line (I need a new one, since my other two are occupied by other machines and I want this DC to have a dedicated line). I'll let you guys know how it goes. Thanks.

[Bill Dufour]

Note the amps for the motor will be higher from single phase into the vfd. Off hand if the motor is 240 volts, 10 amps three phase the vfd will need 240 volts input at 17 amps in plus the vfd efficiency loss.
Square root of three is 1.732. So three phase amps times 1.732 equals single phase amps.
Bill D.

[Chris Parks]

Using a VFD means you can run the DE at the speed you want. I run my cyclone at 70hz and have done for years with no issues which gives me greater air flow but more noise of course.

[Tom M King]

I just use the VFD's for the on off switch and don't have the regular switches anywhere in the circuit. Might be differences in VFD's though. I don't claim to know anything about them. I just hook them up according to instructions and use them. I just use the cheap ones and keep backups, which I have never needed. I run the big Italian bandsaw 10% over speed, and the motor has never even gotten warm running for hours at the time.

[Bill Dufour]

Running a motor under say 75% of full rpm may start to require extra forced cooling for long term use.
BilL D