Vfd selection

Justin.schmidt23

Active Member
Posted this on another forum figured I'd might as well ask here too. I'm planning my 2x72 grinder build and I'm about to grab a 2hp baldor motor and I'm looking at different vfd. Specifically the teco fm 50 it says it input voltage is 380-480 and output is 0-480 I only have 110 in my garage. Do will this work? Or just save my pennies for a kbac 27d?
 
First off, there are several configurations for the TECO FM50, as I understand, ranging in input voltages and hp. The 400v/480v input is going to be 3phase input, 3 phase output, and will NOT work if you only have 110 single phase power in your shop.

You're also going to have a tough time finding a vfd that will supply 2hp at only 110vac input. As far as I know, these don't exist. The most you're going to get from a 110vac circuit is going to be 1.5hp.

Now, the kbac-27 can be switched to run on 110vac OR 220vac input voltage. 110 will run 1.5hp or less, and 220 will run 2hp or less. As far as VFDs for knife making grinders go, you'll likely not find better than the kbac-27, but it is a bit pricey and probably twice the cost of the average fm50, if I'm recalling prices correctly.

I may be mistaken, but I think the only model of the TECO fm50 that runs on 110 will only supply a 1hp motor or less. If you want to power 1.5 to 2.0HP on an FM50, you're going to need a 220vac supply in the shop.
 
Let me jump in here and suggest a 1 hp motor and VFD. I know Ed and a few others run 2hp set ups, but I've been perfectly happy with my 3 phase 1hp Baldor motor running on a 110v single phase VFD.
 
Baldor motors are way over priced. TechTop makes motors for Baldor's European market. The TechTop motors are cast aluminum for better cooling and have several nice features. I think that the TechTop cast aluminum motors are better than the Baldor rolled steel motors.

I believe that a 1.5 hp motor is plenty of power but you can run a 2 hp motor on a KBAC 27 VFD. The book says that you must run a 2 hp motor on 230v power, however, that is for heavy, continuous use (such as commercial HVAC or pumps). We do not use our grinders under heavy, continuous use. If you were to over run your KBAC drive it would just shut off. You just hit the on switch and go back to work.

Check out the motors and VFDs on my website www.WayneCoeArtistBlacksmith.com Let me know how I can help you.


C
 
Well the reason for the 2hp baldor is cause I'm getting it for under 80 bucks with free shipping so I don't really wanna pass that up. I think I'll save my pennies for the kbac
Here's a pic of the motor I'm getting


I haven't bought it yet so if it's a no go let me know please
 
And Wayne I love being able to help out other knife makers when I'm able tof so I'll save the dough and get her the kbac from you!
 
Justin, yes that Baldor motor will work just fine. It's a TEFC motor, 3 ph that has low voltage winding to run on 240vac 3ph. $80 is a good price. You can see list price here: https://goo.gl/HhSoKn
 
My advice is to purchase the KBAC controller. I've spent untold amounts of time trying to help others with the TECO units....they seem to work great in situations where you "set" a given speed and leave it there, but in situations where speeds are often changed (such as a grinder application), they tend to be a royal pain. The KBAC units are just much better suited to a grinder application.

I also noticed that you mentioned you only have 110V in your garage/shop... that means you'll have to install a 220V circuit to use that motor with a VFD, so take that into consideration too. For many that's not a big issue IF you can do it yourself, but depending on your electrical situation, and your comfort level of dealing with wiring, it can get expensive if an electrician is required. :)

Way back when I first moved into our current house, the garage had a single 110V circuit..... doing it myself, I ran an entire new circuit to the garage/finish shop, installed a breaker panel, and then wired the entire building for about $300.
 
Thanks for the advice ed. If I'm not mistaken the kbac will run on 110. I'm electrical retarded so me trying to wire something would end pretty bad
 
If I understand the KBAC manual(s), I believe that the biggest motor you can run on 115V input is 1 1/2HP. For a 2HP, you'll have to have 220V input...... The manual shows that the 27D will only support/run up to 1 1/2hp on 115V input/ max 5.5amps but will support 2HP on a 208/230 input at a max of 6.7 amps. I went back and looked at the pics of the motor plate.... it shows 6 amps on 208/230V. I could be misunderstanding it..... if you download the manual, and check on page 10, it shows........


After looking at it closer, it appears that in order to run anything bigger then 1 1/2HP, it's going to require a 220V input. At least thats what I get out of the above chart.... which is what I was thinking when I wrote the previous post. Better to be sure now rather then wreck a controller or motor....or both. :)
 
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Thanks for looking that up for me ed. That's what I was figuring is the 2hp will run at 1.5hp on 110v but I gotta go up to 220v to get the full 2hp. I'm a buck 50 soaking wet so I'm sure 1.5hp will be plenty
 
Again, I might be wrong, but if the motor draws 6 amps (as it says on the motor plate), and the max on the controller @ 115V input is 5.5, I suspect you're going to burn something up.....whether that be the motor or controller..... I don't know. My guess is the controllers PCB (printed circuit board) will only handle a max of 5.5 amps.....and if the motor tries to draw 6 amps through the PCB of the controller......... hmmmmmm?

Personally I've never tried running a 2hp on anything other then 220V..... so again, I might be totally off here, but then again, I always have been one to ensure whatever I'm using will handle more current then what I'd ever push through it. I'd just hate to see you spend the money on a controller, and burn it out.
 
I kinda see what your saying ed. Electronics is like a foreign language to me. But as it turns out I won't be getting that 2hp motor anyway. I was going to buy it in ebay but my gut told me not to trust the seller so guess I'm back to square one. I'm thinking about getting a 1hp and the kbac24d and calling it a day
 
As I said before:
The book says that you must run a 2 hp motor on 230v power, however, that is for heavy, continuous use (such as commercial HVAC or pumps). We do not use our grinders under heavy, continuous use. If you were to over run your KBAC drive it would just shut off. You just hit the on switch and go back to work.

I learned that directly from the KB representatives at a function in Nashville several years ago. I certainly don't think that they would steer me wrong on this. Further, I have tried it and found it to be correct. I am very careful about what I post here and would not want to post incorrect information.
 
What typically happens with a VFD when you draw too many amps is that it will fault (shut off) due to Overcurrent Fault. You reset the fault, and the VFD will start right back up again. However, drawing too much current too often is the electrical version of wear and tear. Over time things give up when you beat on them too hard. KBAC drives are great little drives, but industrial they are not. I'd be hesitant to run my KBAC the way we run VFDs in factories. (especially since I'm the one paying for it, and I don't have a parts room with ten more). I'm a big believer in giving things a cushion whenever possible. Granted, running a belt grinder is in no way, shape, or form difficult on a VFD. Running your motor at 120Hz for a long time is about the only thing we do that would be considered abusive. When you are hogging steel (profiling blanks) is when you'll work that motor the hardest. Put your hand over the motor housing once in a while. If you wouldn't touch the motor, it's time to throttle down and let it cool. That motor you posted a picture of has Class F insulation. (class F is typical for a motor). True Inverter Duty motors have Class H or I insulation and will take more of a beating before the insulation breaks down the windings ground out, but in my opinion there's no need to pay for an inverter duty motor to run a belt grinder. If the motor needs a break, your back probably does, too.

Something else to consider: most people set up their VFD to allow 2x motor speed. When the potentiometer on the front is set to 100%, the motor will be running at 120Hz. This is going to draw slightly higher amps than the nameplate. This is not a HP issue, it's a cooling issue. Any 60Hz motor running 120Hz for an extended amount of time is going to overheat.

220VAC isn't that hard to come by. I ran my grinder off a 25ft length of SO cord to my dryer outlet for a year. The wife would come yell at me to quit grinding because she needed to dry clothes sometimes, but we made it work. I was renting at the time, so it was a good workaround. Just something to think about.
 
As I said before:
The book says that you must run a 2 hp motor on 230v power, however, that is for heavy, continuous use (such as commercial HVAC or pumps). We do not use our grinders under heavy, continuous use. If you were to over run your KBAC drive it would just shut off. You just hit the on switch and go back to work.

I learned that directly from the KB representatives at a function in Nashville several years ago. I certainly don't think that they would steer me wrong on this. Further, I have tried it and found it to be correct. I am very careful about what I post here and would not want to post incorrect information.


Wayne was posting when I was. He's absolutely right. As I said, if you get into a situation where the VFD is tripping regularly, it's time to run some 220.
 
Wow that's alot of info guys I really appreciate it. So with all that being said a 1hp kbac 24d would do the trick as long as I don't go crazy with it right?
 
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