Not just another dust collection system question....... VFD/flow related

[David Kumm]

Larry, I have three Phase Perfects- 10,20,and 30hp. All were bought used and all have had no issues. I'm a pretty light duty guy though. I also had two Kay RPCs before and they are top of the chain in the rpc world but not as balanced as the PP or as quiet. A used 10 hp goes for 1500-2000, a used 20 hp vfd for 400-600. I run motors from the 1920s forward and never had a problem due to a vfd. I've had motors that didn't like the rpc. Newer motors use much better insulation but in part because the housing size has dropped and steel frames have replaced cast iron. The old motors absorbed heat better. I would not worry about an old motor and a vfd, particularly at 220-240. Most problems I've heard of involved higher voltage motors.

[Rick Fisher]

The 20hp Phase Perfect has been "Perfect" ... I think David would probably agree that they are the Cadillac of phase converters. I would not hesitate to buy one used .. I understand they can be paired up . 20-20 .. or 30-30 as well.

I have a buddy who cant turn his dust collector on (Oneida) if he is standing near his Felder Slider due to the frequency of the VFD .. Its weird.

[David Kumm]

The PP must be paired at the factory. Can't take two separate units and couple them like with an RPC. Dave

[Ryan Mooney]

Ryan, I called Factorymation and talked to a tech for a while, that is where I got that information. And in ads such as this they make reference to it. http://www.ebay.com/itm/Hitachi-WJ20...-/231027875515 What has me concerned is that it is sellers making these claims and not manufacturers. I can find no reference by a VFD manufacturer that this can be done so I am wondering? If this is a real possibility with no drawbacks wouldn't a manufacturer want to increase sales and advertise as such? I do not trust salesmen any farther than I can throw them, and have not even found a link to one working in this manner. I have a small VFD doing this but it was sold that way, in the spec sheet. Maybe they just figure that anyone that is running this big of a motor would have three phase, and I'm sure most are.

So.... with the fact that I have to double the size, and basically double the cost I am rethinking running machines on VFDs instead of a converter. If I find that it is approved and warrenty is still in effect, well then maybe. But the cost savings disappeared with that little tidbit of information. I still want to run the Dust collector on a VFD but will have to think about a Phase Perfect. I thought by now Phase Perfect would have some competition and prices would be coming down, but does not seem to be the case.

I'd looked up the manual for the hitachi as well and while it doesn't have explicit instructions hitachi does have an applications note on sizing for the single phase input case: http://www.hitachi-america.us/suppor...ngle-Phase.pdf

The shortest explanation I found was from http://www.dartcontrols.com/wp-conte...hase-Power.pdf - yaskawa has a somewhat longer explanation: http://www.yaskawa.com/site/dmdrive.nsf/link2/NKOE-7GPJP8/$file/AN.AFD.15.pdf They also have a nice PPT explaining some of that: http://www.yaskawa.com/site/dmdrive.nsf/link2/CAMK-7XFK5Z/$file/PP.SinglePhase.01.ppt

It looks like polyspeed makes one spec'd for single phase input: http://www.polyspede.com/acdrives.html - but looking at the manual they suggest adding dc chokes, etc.. the same as the other vendors likely want and you're still north of a grand for the vfd (no idea what the other parts cost - less than the vfd anyway ).

I think part of the problem is that once you get into this territory its no longer a simple spec to motor size, hook it up and roll setup as it would be for a drive designed for single phase from the ground up - its a bit past where I'd be comfortable wiring it myself unless I was ok with the vfd loosing its magic smoke. Given that I can certainly understand the manufacturers being hesitant to put to much out there and let the installers deal with it (this is sort of past your average joe home owners normal size of equipment )

If you search "vfd derating for single phase" you get a bunch more hits with varying levels of useful.

Also an older thread here: http://www.sawmillcreek.org/showthre...le-phase-input - which is where I actually found the hitachi note.

[Rick Fisher]

The PP must be paired at the factory. Can't take two separate units and couple them like with an RPC. Dave

Good to know .. I wasn't aware of that .

[Rick Fisher]

Remembering back, I bought a Griggio 4hp Jointer way back when .. It was marked as 3KW .. Which made me believe I could simply buy a 3hp VFD for cheap and be off and running ..

A few weeks later I had my PP-20 hp unit laying on a pallet, plugged into the wall ..

Turned out that the Jointer had an Electronic Brake, which stopped the cutterhead super fast, but made using a VFD for conversion impossible .. I had to disconnect the break or find another way to make 3 phase power.

If you like Euro equipment, your going to run into motor brakes. I personally really like the brakes.

When the jointer arrived, I realized that it was more machine than I expected. I really fell in love with industrial grade stuff. So I made the decision to jump into 3 phase power ..

Larry, does your big planer have a brake on the motor ? I would have thought it did ..