need help, servo or VFD?

[hoisee]

Thank you, jraef !

This is what I was searching for! You give me and all members a detail description of this topic. Thank you again.

As for your suggestion PW755, I'm afraid that I can't use it cause our power system is 220v 3phase ac power. I checked the spec it only support at least 380v .... do you have any suggestion?

 

[jdbrandt]

Hello,

We are going to upgrade an old bandsaw so that we can feed the wood automatically. The requirement is easy -> can control its speed and there is a button to let it go back. I planed to use Powerflex525 or Powerflex70 to do the job but my boss prefer servo. What's the suggestion?

I'm new to this area but I had spent must time to research in the network. From what I had learned, I think I can use an FOC VFD and induction motor to do the job easily cause we only concern speed and torque(all speed range). Does this kind of VFD (with encoder) can provide stable speed control like a servo? If cost is not an issue, which one is better to provide a stable adjustable feedrate in this case? Thanks for your help

I thought "VFD" when I saw "...can control speed..", since that almost always means "velocity". And, I seconded myself when you said "..my boss.." and "..servo.." in the same sentence. Servo applies when you are matching POSITION to something else, or need to maintain POSITION with great precision...(among other things), and, by the way, its more than the drive...you need a special motor, motor mount, oh-yeah, motor cables and such.
The torque and speed requirements near 0.00 velocity would be the only thing that would move me away from a VFD (i.e. a traditional VFD), but, even then, I'd be looking at a Movi* drive from SEW if I needed something exotic.
Just my 0.02

 

[hoisee]

I thought "VFD" when I saw "...can control speed..", since that almost always means "velocity".

Sorry for making you confused, English is not my native language please forgive me
If you had noticed someting wrong, please let me know

Btw, I can't edit original post anymore

 

[DickDV]

I'd use a good sensorless vector drive like ABB or the higher performance AB drives. It'll do the job of feeding the stock just fine without the expense and maintenance of an encoder. More than that is really overspecifying unless I've somehow not understood the application.

 

[hoisee]

DickDV,

You understood it correctly, just to feed the stock, a power feeder. Thank you

 

[milldrone]

DickDV,

You understood it correctly, just to feed the stock, a power feeder. Thank you

Ahh! a power feeder. Here are some examples of power feeders for sale. One of them mentions an inverter!
http://leadermacusa.com/lateral-chain-feeders.html
http://www.woodstorm.com/lcfl.htm
https://www.youtube.com/watch?v=NepUTTxqjLA
https://www.youtube.com/watch?v=nVwXaa0ZV4M
Of course these would only be suitable for a horizontal mill but you get the idea!