Thinking of going down that VFD (variable frequency drive) road...

[Nigel]

Hi everyone,

As the title suggests, I’m thinking of going down that VFD road. I’ve searched for and read all the posts on the forum about it, and I’m excited to have fine control over my lathe again.

I have a General 260 with a reeves drive that works not bad actually, but after using electronic variable speed, a reeves just isn’t the same! Like I say, it isn’t bad at all, just two complaints: 1. at some speeds there is harmonic belt vibration/wobble (I think due to the long travel), and 2. it’s kinda noisy. There’s so much going on with multiple belts and pulleys that slide around and, well, it sounds like it.

Thinking this would be a common conversion to wood lathes, I thought I could find simple guidelines online, i.e. what type/size/brand of VFD and motor to use, but to no avail. There seems to be a variety of opinions out there of what “quality” of VFD is required, i.e. the sensorless vector, or vector, vs other “inferior” (and also cheaper) models such as the V/Hz drives.

I’m in the early stages of the process. I feel not too daunted about the project but for getting off on the proper foot, namely, what products to use.

The VFD I’m eying, per a recommendation on another forum is this one, for a 2hp motor: http://www.factorymation.com/s.nl/it.A/id.196/.f I’m quite sure this one is a V/Hz model, i.e. not sensorless vector or vector, but it was recommended. And it is relatively cheaper when comparing with the “better” VFDs. When I think of the CT128 I can’t help believe that it would have a “cheap” VFD and it works just fine (in fact it works very well after reading that the Grizzly counterpart has issues with pulsing at low speeds).

The motor has yet to be obtained (anyone want to trade a 2hp single phase Leeson for similar 2hp 3phase? I have learned that the motor I should have should be an inverter duty 3 phase.

So if any of you can chime in with any experiences, models, recommendations in this process I’d highly appreciate it.

Thanks!
Nigel

[Phred]

Most companies that wholesale wiring supplies to contractors (and individuals) also sell motor controls. It might be worth your while to talk to one or more of them (if any in your area) and get recomendations on the best way to go. ONE of the things to watch for is constant torque at all speeds and you may not need a 3ph motor. Good luck

[Gord Adams]

Hi Nigel

I work with VFD drives a lot. I have had problems lately with the TECO also sold under Westinghouse and Taian brand names. They can be a bear to program even for an experienced user. Have a look at Altivar 11 drives by Square D/ Telemechanique. Much better drive and still relatively cheap, you can easily put on a remote speed dial and a STOP/START station if you desire it.

[Nigel]

Awesome, thanks for the suggestions fellas.

Gord, thanks for the mention of a drive that you like, although I'm having trouble finding info on the Square D Altivair stuff (online). I'll for sure make some phone calls tomorrow (since today's Sunday).

Any experience with the "Sabina" line of VFDs? I'm asking because I found this on the auction site...

http://cgi.ebay.ca/Sabina-VFD-AC-Inv...item45f05894c6

Thanks again,

Nigel

[MAWarner]

Nigel
I can get you a 25 hp 3 phase

[Phred]

Square D = Telemechanique Try their site

[Nigel]

Nigel
I can get you a 25 hp 3 phase

Sweet now that would handle some big bowls although i think the VFD would run me a pretty penny...

[MAWarner]

When we took down the old plant theire was a few of these motors left but just too big for workshop needs. What are you going to pay for a 2 hp 3 phase? for the varible speed project.

[Nigel]

I'm keeping my eye open for a used motor. I found one that was perfect and only $95... except it was 5hp. When I started researching I found that the VFD for 5hp would be far more expensive than a 2hp model.

I'm thinking of posting an ad for a swap for my 2hp 1 phase leeson. It's in great shape though and no doubt would have a use down the road for me...

Just keeping my eyes open for the right thing at this stage.

[MAWarner]

Well at least you can turn while you wait. It will pay to wait for the deal. Anyone that replies to your ad I think I would ask how much they want for their motor without the trade as a 2 hp single phase can certainly be very handy if in future you need one for dustcollector, bandsaw, drum sander, planer. Most everything today has a 2 hp motor on it. It would be well worth keeping.

[Gene45]

Here are some surplus motors for sale in Calgary.

http://www.wermac.com/surplus.html

Their VFD's are too expensive but you can get one for your 25 HP machine.

Or look at automationdirect. for both .

http://www.automationdirect.com/adc/Home/Home

I priced out a 1HP motor and drive for $236 US fro both.

I believe you have to phone them to get then to ship to Canada.

[J.P. Rap]

I'm keeping my eye open for a used motor. I found one that was perfect and only $95... except it was 5hp. When I started researching I found that the VFD for 5hp would be far more expensive than a 2hp model.

I'm thinking of posting an ad for a swap for my 2hp 1 phase leeson. It's in great shape though and no doubt would have a use down the road for me...

Just keeping my eyes open for the right thing at this stage.

You can use the 5HP and downgrade it when you program the VFD. That is provided you have the programing parameters needed to do so. Some units designed for weekend warriors don't have the full range of parameters accessible.
Simply put, you're programming the VDF to not deliver more then 2 HP. The motor will work just fine and last longer since it's built to deliver 5 HP. If you're unsure, ask the vendor where you buy your VDF.
HTH

[Nigel]

You can use the 5HP and downgrade it when you program the VFD. That is provided you have the programing parameters needed to do so. Some units designed for weekend warriors don't have the full range of parameters accessible.
Simply put, you're programming the VDF to not deliver more then 2 HP. The motor will work just fine and last longer since it's built to deliver 5 HP. If you're unsure, ask the vendor where you buy your VDF.
HTH

OO very cool about using a larger motor--I figured that might be the case.

I assume it would have to be an inverter duty, constant torque model to be effective, correct?

[J.P. Rap]

OO very cool about using a larger motor--I figured that might be the case.

I assume it would have to be an inverter duty, constant torque model to be effective, correct?

I can't say for sure. I don't know that much about them. Inverter duty is definitely the better way to go but mine isn't and it does just fine. Plenty enough power for anything I've thrown at it and no overheating even at low speeds.
That said, my inverter (Siemens) is of a higher quality then the less expensive models being sold. That may have something to do with it.
If you think you might need a better motor...why not try the motor you have first? It may work out fine but if it doesn't, you can always upgrade later. Nothing lost.
I'm not familiar with the inverter you linked to so I can't help you there. Perhaps a question to them about the motor you want to use (mentioning the downgrade) might shed some light.

[Nigel]

I can't say for sure. I don't know that much about them. Inverter duty is definitely the better way to go but mine isn't and it does just fine. Plenty enough power for anything I've thrown at it and no overheating even at low speeds.
That said, my inverter (Siemens) is of a higher quality then the less expensive models being sold. That may have something to do with it.
If you think you might need a better motor...why not try the motor you have first? It may work out fine but if it doesn't, you can always upgrade later. Nothing lost.
I'm not familiar with the inverter you linked to so I can't help you there. Perhaps a question to them about the motor you want to use (mentioning the downgrade) might shed some light.

The motor I have is single phase, which, as far as I know, doesn't work with the three phase output of the VFD. I'm new to this so if I'm missing something and I can just use my single phase Baldor, I'll be happy to try it as you suggest! Sounds too good to be true though

[billh]

No, you need to use a 3-phase motor with the VFD. There are VFDs that will work with certain types of single-phase motors but I think they are quite expensive and I doubt if the performance is as good as a 3 phase setup.

The VFD output will be current limited to match the motor BUT the issue is for totally-enclosed, fan cooled (TEFC) motors which are common in WW equipment is the low motor RPM means the fan is not rotating fast enough to produce good cooling air-flow. The inverter duty motors address this issue, and perhaps others. If you think your motor is getting too hot you can blow a small external fan on it.

billh

[Nigel]

No, you need to use a 3-phase motor with the VFD. There are VFDs that will work with certain types of single-phase motors but I think they are quite expensive and I doubt if the performance is as good as a 3 phase setup.

The VFD output will be current limited to match the motor BUT the issue is for totally-enclosed, fan cooled (TEFC) motors which are common in WW equipment is the low motor RPM means the fan is not rotating fast enough to produce good cooling air-flow. The inverter duty motors address this issue, and perhaps others. If you think your motor is getting too hot you can blow a small external fan on it.

billh

Thanks Bill that's what I thought

[Nigel]

I took the General 260 apart last night and took some pictures today if anyone's interested in following the project.

The old motor is a Baldor 2hp and of course has the starter and switch, which I've now removed. Any VFD experts out there know if I can use the switch as a remote switch for it? Or how hard that would be to do?

I'm thinking that the switch, starter, and motor would do nicely on an old bandsaw... so now my eyes are open for some old iron...

As you can see the old reeves belt is wide at 1" and has "teeth" (for lack of an official term). Do you think it would be sufficient to simply use the existing pulleys? I can get the motor up close enough to the spindle to use the belt that's around it, which would mean not having to remove the spindle and find another sheave, etc., which I would rather not do if I don't have to. The sheave on the spindle is 3.5"d and on the motor shaft it is 2"d. I'm aware of the speed issues, i.e. getting fast enough for spindle turning, and I'm considering trying to find a larger one for the motor shaft for that application...

Anyway enjoy the shots and any comments are welcome!

[J.P. Rap]

The motor I have is single phase, which, as far as I know, doesn't work with the three phase output of the VFD. I'm new to this so if I'm missing something and I can just use my single phase Baldor, I'll be happy to try it as you suggest! Sounds too good to be true though

I'm sorry. I could have sworn I read you had a 5HP 3 phase motor. Must have been the wine.
Yes. It needs to be 3PH.
Use the belt you have if you can. A good inverter will allow you to speed up the motor as much as 100%.
Mine allows for 200%+ over current at start up 150%+ continuous. That >4300 RPM at the motor.
I wrote "+" because it allows for much more but recommends against it. In reality I could rev this motor up until it tore itself apart.

You can use the original switch but only to power the inverter (turn power on/ff to the inverter). You use the inverter for motor on/off, reverse etc. If you connect a remote switch to it, it's normally (not always) low voltage so that switch won't work for that. The draw on the inverter is minimal so a DPDT toggle switch will work fine for power but a mag switch is a nice feature.
HTH

[Nigel]

I'm sorry. I could have sworn I read you had a 5HP 3 phase motor. Must have been the wine.
Yes. It needs to be 3PH.
Use the belt you have if you can. A good inverter will allow you to speed up the motor as much as 100%.
Mine allows for 200%+ over current at start up 150%+ continuous. That >4300 RPM at the motor.
I wrote "+" because it allows for much more but recommends against it. In reality I could rev this motor up until it tore itself apart.

You can use the original switch but only to power the inverter (turn power on/ff to the inverter). You use the inverter for motor on/off, reverse etc. If you connect a remote switch to it, it's normally (not always) low voltage so that switch won't work for that. The draw on the inverter is minimal so a DPDT toggle switch will work fine for power but a mag switch is a nice feature.
HTH

Hi JP, no you're right, I wrote that I had found a 5hp 3ph, but I didn't buy it. I wasn't clear...

As for the speed control, do you ever run your motor at 4000 rpm??? that seems wild if it's a regular 1725... but that would solve the speed issues. What sort of pulley arrangement do you have on your setup?

Oh and my 2hp inverter arrived, the 2hp GS2 22PO from here: http://www.automationdirect.com/adc/...AC%29/GS2-22P0

And here's the specs on it: