Motor speed controller

D

David Danek

Member
Hello, I am in the process of picking up parts to build a knife grinder. I just managed to pick up a 4HP 22V motor. Its quite heavy and large, so I would prefer to have a speed controller then move the motor to switch belt locations on pullies. I found this on Ebay and was wondering if something like this would work.

http://www.ebay.ca/itm/US-52-220V-5...302588?hash=item35e53dd9bc:g:AdIAAOSwT6pVlSdV

I was looking at VFD's but are quite expensive and have no need of changing the voltage in my shop. There are ones from asia that are cheap but look used as well.

Also wondering if there are any people around the Edmonton area that have a lathe that makes wheels for knife grinders.

Thanks a bunch.

Dave
 
Can you provide a pic of the data plate on the motor? At 22volts I am thinking maybe it is a DC motor or, perhaps the 22 is a misprint and it is actually a 220v AC motor?
 
Hi David, looked at that drive and it is not rated for a 4hp motor...it is for a fractional 1/5hp gearmotor or small pump. If want to run a motor that big you gonna have to get one rated by horsepower of motor like this Leeson http://www.ebay.com/itm/5-hp-ac-dri...757485?hash=item43dbc25f2d:g:sU8AAOSw-jhUA00j which is for a 5hp but might have to upsize as sizing goes from 3 then to 5 hp on many drives.
KB electronics sells drive boards, rheostats, etc and can save some money if want to build one. I would probably find a good used one, as have done that and worked out.
 
Hey David. Having a variable speed control versus a belt control is so much nicer. The controller that you linked though will not work for two reasons. First, its 50 Hz, which would be a European standard for power. Canada uses the same power standard as the U.S., which is 60Hz power. Secondly, it would be too light duty. From the "25W" sticker on the side of it I would think it is a 25 Watt controller. The motor you mentioned, assuming like Jay said is 220v single phase, would draw about 21 amps of power equaling 4620 Watts; way more than that controller can handle.

To have a variable speed control for a motor of that size, there is no real way around buying a VFD. I would suggest looking on surplus equipment sites, ebay, and discount electronic sites. Remember, a good VFD will also allow you to run a three phase motor off of 220v Single Phase, which you probably have.
 
David Danek said:
Hello, I am in the process of picking up parts to build a knife grinder. I just managed to pick up a 4HP 220V motor. Its quite heavy and large, so I would prefer to have a speed controller then move the motor to switch belt locations on pullies. I found this on Ebay and was wondering if something like this would work.

http://www.ebay.ca/itm/US-52-220V-5...302588?hash=item35e53dd9bc:g:AdIAAOSwT6pVlSdV

I was looking at VFD's but are quite expensive and have no need of changing the voltage in my shop. There are ones from asia that are cheap but look used as well.

Also wondering if there are any people around the Edmonton area that have a lathe that makes wheels for knife grinders.

Thanks a bunch.

Dave
Click to expand...
Apologies, it is a 220Volt motor. hard typing on a cell phone. :)
 
Problem is, that speed controller is also a phase converter. Im sure that is what boosts its price higher. I have 220 Volt in my shop so no need to convert the voltage at all.
But thanks.
 
My advice, you need to find a smaller motor. 4hp is huge and the price of the VFD to handle it will be much higher, in fact, finding a single phase input, 4hp 3 phase output VFD might be hard, not sure if they even make those. 1hp motor is adequate, 2hp is plenty.
 
There is a reason it is also a phase converter. Most VFD's do not play well with single phase motors. Like I said above, you can find some that do, but most are setup for three phase output with single or three phase input. This has to do with how single phase motor starting circuits function and how electrically they operate. The controller Ausbrooks linked, and pretty much all the ones you see on KMG's online, only have three phase output which will not work on your motor if it is single phase. After going back and looking at various VFD literature I have; the single phase/single phase vfd's I see only go up to about 1-1.5 HP.

Taking a guess that your motor is single phase, you might be stuck with belts for the moment and figure on hunting up a three phase motor with a VFD later on.
 
In general, VFDs for single phase power input are going to limit you to no more then a 3hp/3-phase motor. Once you get larger then a 3hp motor, the VFDs are going to be for either 3-phase or 460V input power. Let me qulify that statement..... Personally the only VFD I would consider for a grinder application is the KBAC brand, because I have dealt with most of the other brands over the years, and simply avoid them, and encourage others to do likewise. Compared to the KBAC brand, all the others are simply not worth fooling with. For single phase input, KBAC VFDs top out at 3hp.

IF you want to have variable speed on your grinder (not even considering step pulleys), my best advice is to purchase a 3-phase motor, and matching KBAC VFD. Personally, all my varibale speed grinders have 3hp motors, with KBAC-29D VFDs (controllers) This outfit generally has the best selection and prices of motors and controllers.... http://www.electricmotorwholesale.com/ I've purchase several motors and VFDs from the over the years, and have had great service and quick delivery..

About the only option for changing speeds with the motor you have...is step pulleys.
 
CMS3900 said:
After going back and looking at various VFD literature I have; the single phase/single phase vfd's I see only go up to about 1-1.5 HP.
Click to expand...

Are you saying you found a VFD that will work with a single phase motor? If so, can you link to it?

Ken H>
 
CMS3900 said:
There is a reason it is also a phase converter. Most VFD's do not play well with single phase motors. Like I said above, you can find some that do, but most are setup for three phase output with single or three phase input. This has to do with how single phase motor starting circuits function and how electrically they operate. The controller Ausbrooks linked, and pretty much all the ones you see on KMG's online, only have three phase output which will not work on your motor if it is single phase. After going back and looking at various VFD literature I have; the single phase/single phase vfd's I see only go up to about 1-1.5 HP.

Taking a guess that your motor is single phase, you might be stuck with belts for the moment and figure on hunting up a three phase motor with a VFD later on.
Click to expand...

if you are using 240(or 220 or 230) 3hp is usually the limit. Leeson, allen-bradley, TECO and others make unit that will go to 3hp.
 
http://www.invertekdrives.com/variable-speed-drives/optidrive-e2-single-phase/ They make VFD's for certain types of single phase motors. http://www.bardac.com/shop/price-ode2.php if you scroll to the bottom it shows up to 1.5 HP. I have always used three phase vfd's however. Otherwise for single phase your stuck with a variac or something, which is terrible for this application.

The info that Mr. Caffrey said is basically what I was getting at for the OP. 4 hp to begin with is a oddball motor and Anthony was right in the fact its overkill for a 2x72 grinder. I agree that the best thing he can do is either A: use step pulleys and the motor he has, or B: buy a new motor and controller. I actually need to check out the company Mr. Caffrey linked because there about 10 minutes from my house. Also a +1 for the KBAC brand.
 
Well shucks, I guess I didn't go far enough down the page, and at $418 - "IF" that is for a NEMA 4X enclosure isn't such a bad price considering.... not at all. AND - I do stand corrected, it is a VFD since it does vary the frequency as per the specs. That is the first time I've seen those. I've worked with 3 ph VFD's for many years in industry. Learn something new everyday is my goal, and I've learned today.

Ken H>
 
I wish i hadthe funds to buy a new motor and a high end vfd. I was able to post a pix. of the motor plate.
At this time i cant do much more for a motor. Got this one real cheap, and now saving up $450 to get a good set of wheels for the grinder on ebay. Unfortunately they are in the U.S. so the exchange rate is a killer. Was hoping to find a solution for speed control that was more in my budget. LOL.hate to but may have to go with pullies. The design i have plans for is great and with such a beefy motor im thinking of incorperating a 12" sanding disk on the side.
 
belt-grinder-38.jpegKMG-PL2-t.jpgthese are the two designs I am looking at. Have the plans for the first one.
 

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I would rock that first design with the motor you have and some step pulleys to get moving. By putting the motor on a hinge it would make it easy to change speeds. I saw a thread on blade forums earlier today that talked about contact wheels you might want to look at. I dunno what the quality is though. I know I tried to cheap out and buy a 10 inch wheel from grizzly and machine it for bearings and it did not work. I ended up buying one of the 10" wheels Beaumont Metal Works sells from a member on here and it works flawlessly. Another thing to look into if you want to save on wheels is a radius platen. Ill plug Nathan there only because I have read a bunch of feedback and people seem to like his work. I plan on ordering one in the future just to try.
 
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