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Dust Collector with phase converter

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Forum topic by turbo1974 posted 07-11-2019 01:27 AM 313 views 0 times favorited 20 replies Add to Favorites Watch
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turbo1974

10 posts in 41 days


07-11-2019 01:27 AM

I got a great deal on a Powermatic 1900TX dust collector from a local shop that shut down. Unfortunately, it’s a 3 phase system. It’s practically brand new and came with a literal truckload of ducting, adaptors and blast gates. I know I’m going to have to run it on a phase converter etc.. but how do I switch it? Can I use a tool trigger like the iVac pro wired between the phase converter and the 220 1ph outlet?


20 replies so far

View SweetTea's profile

SweetTea

438 posts in 1078 days


#1 posted 07-11-2019 09:16 AM

That is a very nice unit from Powermatic. I just picked up a 10HP dust collector for under $325 myself. For your unit, with it just being a 3HP you could go with a VFD which is a digital phase converter or you could go with an RPC which is a big 3 phase electric motor controlled by a panel that goes on the wall next to or above the motor. A VFD for that size unit will cost you between $300 and $500 if I had to guess. I would get in touch with Jack Forsberg (I may have butchered the spelling lol) as he builds custom VFD’s and is extremely helpful. I would personally get an RPC in the range of a 20hp to 30hp range. With an RPC you can hook it up to multiple 3 phase machines. With a VFD you must have a separate VFD on each machine.

View Fred Hargis's profile

Fred Hargis

5585 posts in 2911 days


#2 posted 07-11-2019 10:26 AM

The VFD I have on my lathe isn’t “instant-on” when you power it up. It takes a few seconds for the VFD to generate the 3 phase power to the motor, and I suspect that would be the case with others (This is a GE industrial VFD). So while I’m guessing you could use a remote to switch the VFD on/off to power the DC; I’m thinking it may have some delay in how quickly it gets going. Others may have some better insight. You would have to do something about any switch that might be between the VFD and the DC motor, that might be as simple as leaving it “on” all the time.

-- Our village hasn't lost it's idiot, he was elected to congress.

View ibewjon's profile

ibewjon

679 posts in 3211 days


#3 posted 07-11-2019 11:30 AM

I didn’t look at the unit info, but I would change the motor to single phase. You don’t need speed control and you want instant on / off. You need to turn the vfd on / off, not the motor it feeds. If you simply remove the load while leaving the vfd energized, it will usually trash the vfd. And why run a large motor to generate 3 phase to run the DC? Not at all energy efficient.

View clagwell's profile

clagwell

29 posts in 211 days


#4 posted 07-11-2019 02:47 PM

... Unfortunately, it s a 3 phase system.
- turbo1974

I would consider that to be quite fortunate actually. With a 3 phase motor you’re able to use a VFD. The VFD allows you to speed up the fan to better match whatever resistance you have in your ducting and entrance hoods. A commercial version of this approach is the Oneida Smart system.

Obviously you have to monitor the current so you don’t overload the motor but most VFDs will display the motor current.

I have heard that there may be some VFDs that allow you to do this automatically. They apparently can be programmed to adjust frequency to maintain a current limit.

I think Fred’s delay issue probably comes from switching the power to the VFD, It takes some time to boot the system. Normally you would use the low voltage remote capability to enable power to the load, leaving the VFD itself powered.

It will take longer to spin up the fan however. To limit the start surge a VFD is normally programmed for a controlled ramp up rate.

-- Dave, Tippecanoe County, IN

View RobHannon's profile

RobHannon

276 posts in 949 days


#5 posted 07-11-2019 03:13 PM

I would go with a VFD for that. Maybe do some research on if the resistive motor brake options on VFD is a good or bad thing for a DC. I also would not go over the expected Hz to increase RPMs. That impeller may not be rated to go faster. Slower probably would be fine.

As far as switching on and off, I would do it through one of the inputs on the VFD and not put anything between the VFD output and the 3phase motor.

View clagwell's profile

clagwell

29 posts in 211 days


#6 posted 07-11-2019 07:46 PM



I would go with a VFD for that. Maybe do some research on if the resistive motor brake options on VFD is a good or bad thing for a DC. I also would not go over the expected Hz to increase RPMs. That impeller may not be rated to go faster. Slower probably would be fine.

- RobHannon

I can’t think of any good reason to add braking to a DC.

Any RPM increase would be moderate. HP varies with the cube of RPM so, for example, if with a particular tool port the current draw was only half the motor FLA you could then increase the RPM by the cube root of 2 or about 1.26, 26%. That would increase flow by the same amount and pressure by the square of that, or about 60%. 3450RPMx1.26 is about 4350RPM, so not a huge increase.

It would certainly be prudent to put a maximum frequency in the VFD settings.

There are not many good reasons to go slower.

-- Dave, Tippecanoe County, IN

View turbo1974's profile

turbo1974

10 posts in 41 days


#7 posted 07-11-2019 07:54 PM

If I used a VFD I could set it up to take feedback from an in-duct pressure (vac) sensor to schedule RPM. Motor current may not be an excellent indicator depending on where on the fan curve (pressure/volume/efficiency) it is running. For my 3hp motor I’ve heard I need to upsize the VFD by 50%.

View MrUnix's profile

MrUnix

7404 posts in 2617 days


#8 posted 07-11-2019 07:57 PM

I’d swap the motor out or run it on a VFD. Being intermittent, using a RPC would be, IMO, a PITA, since you would have to first fire up the RPC and leave it running even when the DC is not in use. A static phase converter would kill approx. 1/3 the HP, making the DC under perform and possibly causing damage to the motor. A VFD, which can be had for about $200 for that machine, is serious overkill IMO… 99% of what makes a VFD useful would be going to waste – but it may be a cheaper route than trying to find a single phase 3hp motor.

Cheers,
Brad

PS: If you did switch (on/off) the power to the VFD as mentioned, then you will get the startup delay that Fred indicated. For instant on/off, you would need to use the start/stop inputs on the VFD itself.

-- Brad in FL - In Dog I trust... everything else is questionable

View Fred Hargis's profile

Fred Hargis

5585 posts in 2911 days


#9 posted 07-11-2019 08:28 PM



If I used a VFD I could set it up to take feedback from an in-duct pressure (vac) sensor to schedule RPM. Motor current may not be an excellent indicator depending on where on the fan curve (pressure/volume/efficiency) it is running. For my 3hp motor I ve heard I need to upsize the VFD by 50%.

- turbo1974


You can make this as complicated as you want…but ther’s not much reason to do that. Set it up to run at it’s stated RPM, and cut wood.

-- Our village hasn't lost it's idiot, he was elected to congress.

View ibewjon's profile

ibewjon

679 posts in 3211 days


#10 posted 07-11-2019 09:05 PM

Yes, a single phase input / 3 phase output vfd must be upsized. Properly sized for the intended load.

View MrUnix's profile

MrUnix

7404 posts in 2617 days


#11 posted 07-11-2019 09:15 PM

Yes, a single phase input / 3 phase output vfd must be upsized. Properly sized for the intended load.
- ibewjon

Not entirely correct. You can find 3hp VFD’s all day long that support single phase input. It’s when you start getting into the 5hp + range, where they want 3 phase input only (and you are only feeding it single phase), that you need to start playing with de-rating the unit.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View turbo1974's profile

turbo1974

10 posts in 41 days


#12 posted 07-11-2019 09:26 PM



Yes, a single phase input / 3 phase output vfd must be upsized. Properly sized for the intended load.
- ibewjon

Not entirely correct. You can find 3hp VFD s all day long that support single phase input. It s when you start getting into the 5hp + range, where they want 3 phase input only (and you are only feeding it single phase), that you need to start playing with de-rating the unit.

Cheers,
Brad

- MrUnix

That’s the wisdom I needed! Thanks Brad! I was under the impression that I had to de-rate even with a unit that was a 1ph input. Sounds like I’m going to buy a 3hp VFD. Any recommendation or brands/units to stay away from?

View turbo1974's profile

turbo1974

10 posts in 41 days


#13 posted 07-11-2019 09:33 PM


If I used a VFD I could set it up to take feedback from an in-duct pressure (vac) sensor to schedule RPM. Motor current may not be an excellent indicator depending on where on the fan curve (pressure/volume/efficiency) it is running. For my 3hp motor I ve heard I need to upsize the VFD by 50%.

- turbo1974

You can make this as complicated as you want…but ther s not much reason to do that. Set it up to run at it s stated RPM, and cut wood.

- Fred Hargis

Thanks Fred! I’ll probably do what you say and fix speed at 3450RPM but part of my fun is the invention of it all too.
I am a specialist in turbocharging (hence my name) so tuning a fan is a space I feel comfy in. Who knows what kind of invention space there is there. As they say its not the destination but the journey!

View MrUnix's profile

MrUnix

7404 posts in 2617 days


#14 posted 07-11-2019 09:38 PM

That s the wisdom I needed! Thanks Brad! I was under the impression that I had to de-rate even with a unit that was a 1ph input. Sounds like I m going to buy a 3hp VFD. Any recommendation or brands/units to stay away from?
- turbo1974

One of the more popular units, and on the lower end of the cost scale, is the Westinghouse TECO drives… You can get an FM50 V/Hz drive for a bit less than $200 (such as here), which is really all you would need. You can also find no-name brands cheaper on the bay, but those can be hit-or-miss…

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View ibewjon's profile

ibewjon

679 posts in 3211 days


#15 posted 07-11-2019 10:37 PM

I guess we always upsized them to be sure.

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