VFD Options

[Rob Anthony]

I just purchased a new (to me) 1966 Unisaw with a 2 hp 3 phase motor. I'm going to put a VFD on it, but there are a few of them out there at the same price point.

The options I have are:

WEG CFW 10 http://dealerselectric.com/item.asp?PID=480

Taian 200N2215M http://dealerselectric.com/item.asp?PID=523

TECO FM50 http://www.factorymation.com/s.nl/it.A/id.4780/.f?category=16400


Does anyone have any experience with these VFDs and those who have them, which would you recommend?

Thanks in advance,
Rob

[Matt Meiser]

I used the TECO FM50 on a lathe and didn't have any complaints. It was easy to wire and program. Other than using it to run a 3ph motor on single-phase power, about the only feature I can think of that you'd possibly want is to add a brake feature to stop the blade quicker when you hit stop. You'll probably want to buy the optional braking resistor if you do.

[M Toupin]

Rob,
I'm running two FM50s, one a 2hp on a lathe and a 1hp on a drill press. For your application I'd stick with cheap and simple like the FM50. The FM50 is older technology with out all the bells and whistles the more expensive units have.

VFDs don't like being shut off under lead so you need to start it first. The wiring is not difficult, if you can wire a lamp you can wire up a VFD. Here's a pic of the VFD on the drill press. Note the on/off switch which controls the VFD. The original on/off switch is wired into the VFD as a remote switch to actually start and stop the DP. You actually could start your VFD from the keypad, but that would get old quick trying to hit that little button. I'd use the original switch on your saw just as i did on the DP to start and stop the saw.

76629


The FM50 has a limited ability to decelerate without the breaking resistor. Breaking resistors are only needed if your trying to stop a motor very fast or quickly decelerating a heavy load, a table saw is neither. I've got the 2hp unit (without a breaking resistor) on my lathe set for a 3 sec deceleration, it works fine with even a heavy blank. I would not waste the money on the resistor.

Mike

[Ken Deckelman]

I have a FM50 on my metal lathe, no regrets here.

[Rick Christopherson]

First off, you really do not want to put a brake on a tablesaw motor unless you make some preparations to keep the blade's momentum from unscrewing the arbor nut. For most blades, simply tightening the arbor nut more than you normally have to is sufficient. However, for dado blades, there is enough mass behind the blade and enough slip between the plates that is can unscrew if stopped too quickly.

The VFD does have a braking function without the need to install an external resistor and I think you would be OK with using this.

Secondly, you do not re-use the existing motor contactor on the saw. Doing so will not only damage the VFD, but it also wipes out many of the features too.

The FM50 is the lowest cost VFD I have found, and you can set this up for use with standard momentary On/Off control buttons (like a magnetic starter uses), but you cannot do this if you also use the braking function of the VFD.

For $10 more, I prefer the GS1 from Automationdirect.com GS1-22P0 (http://web4.automationdirect.com/adc/Shopping/Catalog/AC_Drives/GS1_%28120_-z-_230_VAC_V-z-Hz_Control%29/GS1-22P0)
This VFD has all of the bells and whistles at the same price. Connecting standard push button controls is straightforward because all of the necessary inputs and self-sustaining relay are built in.

Mike Toupin: I can't tell from the way your posting is worded if you are controlling the VFD with the existing DP switch, or if you are sending the VFD output through the existing switch. If it's the former, I apologize, but if it is the latter, I strongly suggest you consider changing this. You do not want to start a VFD separately from connecting it to a load.I have a feeling that you already know this, but your FM50 does support remote Start/Stop/Forward/Reverse.

[M Toupin]

Mike Toupin: I can't tell from the way your posting is worded if you are controlling the VFD with the existing DP switch, or if you are sending the VFD output through the existing switch. If it's the former, I apologize, but if it is the latter, I strongly suggest you consider changing this. You do not want to start a VFD separately from connecting it to a load.I have a feeling that you already know this, but your FM50 does support remote Start/Stop/Forward/Reverse.

With all due respect Rick, If I wanted your advice I'd have asked for it... I've got two FM50s running right now and both work flawlessly. Believe it or not one doesn't need to be a an electrical engineer to correctly wire a VFD, it's really not rocket science. Oh, and this is really going to blow your mind, I even wired the remotes and programed it all by myself... I didn't even have to ask for help.

BTW, using a remote on the FM50 does NOT make the breaking function inoperable.

Mike

[David G Baker]

I didn't read much respect in your post.

[Matt Meiser]

That GS1 you linked to requires a 3-phase input. I would assume, because I can't think of any reason to run VFD on a table saw other than for phase conversion, that the OP needs a single phase input. The GS2 which has single phase inputs for a 2HP motor is close to twice the price.

I think Rick is saying that the inputs to the FM50 need to be sustained. If that's the case, using a SPDT relay downstream of a set of pushbuttons or even the original controls would give you a contact to use for the input to TM2 PIN3. Factorymation has relays for a few dollars.

There is some reasonable amount of braking that will cause the a blade not to spin loose. Obviously you aren't going to want to stop it on a dime or you'll have a problem, but bringing it to a stop in a few seconds would add some convenience and safety.

My reasoning for the resistor was to move some of the braking heat, should you choose to use braking, out of the electronics. Actually though, after looking at the manual, its not even an option for the FM50-201.

[Rob Anthony]

Matt, you're correct that I want the VFD because I only have 220 1 phase.
As far as operation is concerned, what I'm envisioning is hooking the VFD to the wall beside the 220 socket. I'd like to go socket -> VFD -> Saw switch. I'd love to have it setup so that I can turn on the VFD and then run the saw with a start/stop switch as I would with the saw normally.

As far as soft start and motor braking go, I'd like to have them if it doesn't add a lot of complexity to the operation. As far as braking, I can see some instances where it would be beneficial.

Rick, The saw currently has an Allen Bradley manual start switch, but I'd have no problems with replacing it with another on/off relay type switch. Both the WEG and the Taian have a lot more features than the TECO. The Taian manual http://www.teco.co.uk/docs/drives/legacy/n2/N2%20manual.pdf

shows that it has a built in braking resistor. Also, It looks like it would be possible to wire up a standard on/off type switch for soft start/braking programming and perhaps even a large emergency off push button with a fast brake.

http://i28.photobucket.com/albums/c223/homebrewer27/TaianSwitchWiring.jpg

It looks like the Taian is pretty full featured and for $150 would probably do the trick. It's the same price as the TECO and it gives a lot more options which wouldn't be too bad, even if I don't use them.

[Rick Christopherson]

I'd like to go socket -> VFD -> Saw switch. No, this is the point that someone else took offense to, and it was the reason I pointed it out in the first place. You cannot put a switch between the VFD and the motor. Doing so risks damage to the VFD.

If the existing motor control switches are the low-voltage, momentary pushbuttons, then yes, you can reuse them for controlling the VFD. If the motor starter is the mechanical type push buttons that physically close the motor contactor relay, you can still reuse it if you want, but just not as a high-power contactor that it was intended. You would be better off selling the contactor and investing in a simple set of pushbuttons to give you the same function.

The top diagram in your last posting gives you this type of function, and the controls will operate similar to what you are accustomed to. I didn't review the manual for your model, but I believe you will need to program the VFD to perform this function, but that generally is just a matter of changing a couple of parameters from the display.

On the other hand, you can certainly use a basic On/Off switch (non-momentary) but most people prefer the momentary push buttons for larger tools.

Most VFDs will accept single-phase input, but some may not provide full power at the output as a result. I forgot that the 2-hp GS1 was rated for 3-phase input, but I also suspect that it would still provide nearly full power, if not full power even with single-phase supply.

[Ken Deckelman]

As far as operation is concerned, what I'm envisioning is hooking the VFD to the wall beside the 220 socket. I'd like to go socket -> VFD -> Saw switch. I'd love to have it setup so that I can turn on the VFD and then run the saw with a start/stop switch as I would with the saw normally.

This won't work, You CANNOT have a switch between the VFD and the motor. To control the VFD you can rewire your existing switch for the contact closures, you can even use small wire as these are low voltage connections.

On my metal lathe, I rewired the drum switch for the FWD-OFF-REV operation of the VFD, and added a potentiometer for speed control.

There are a couple pictures in this ALBUM (http://picasaweb.google.com/kdeckster/Clausing4900)

[Rob Anthony]

No, this is the point that someone else took offense to, and it was the reason I pointed it out in the first place. You cannot put a switch between the VFD and the motor. Doing so risks damage to the VFD.

If the existing motor control switches are the low-voltage, momentary pushbuttons, then yes, you can reuse them for controlling the VFD. If the motor starter is the mechanical type push buttons that physically close the motor contactor relay, you can still reuse it if you want, but just not as a high-power contactor that it was intended. You would be better off selling the contactor and investing in a simple set of pushbuttons to give you the same function.

The top diagram in your last posting gives you this type of function, and the controls will operate similar to what you are accustomed to. I didn't review the manual for your model, but I believe you will need to program the VFD to perform this function, but that generally is just a matter of changing a couple of parameters from the display.

On the other hand, you can certainly use a basic On/Off switch (non-momentary) but most people prefer the momentary push buttons for larger tools.

Most VFDs will accept single-phase input, but some may not provide full power at the output as a result. I forgot that the 2-hp GS1 was rated for 3-phase input, but I also suspect that it would still provide nearly full power, if not full power even with single-phase supply.


I see. So the wiring would go Wall Socket -> VFD -> Motor and there would also be wires from the VFD to the switch controls.

The switch on my Unisaw is not original and is pretty worn so I'll probably just wire in a new switch. I'm going to go ahead and order the Taian so I can get this thing running by Christmas.

This site is a fantastic resource and I really appreciate all of the help!

-Rob

[Rick Christopherson]

Yes, the wiring would go outlet-> VFD -> Motor.

A 1966 3-phase Unisaw is most likely using low-voltage controls, where the start and stop buttons are the simple momentary push buttons I mentioned previously, and the motor contactor is located in a large junction box on the back of the saw. If this is the case, then don't be so quick to discard those switches. Pretty much none of the components in the rear junction box would be needed though.

On the other hand, you said the switch was replaced, so it is hard to say what you have now.