Grinder motor question...

MadMalinois

MadMalinois

Member
Hello all,

My name is Jeff and I have a question about using the motor that I purchased over a year ago. Most likely before knowing which one was best for the application. I bought the motor intending on going with the NWG plans from USA KM. Ended up scrapping that idea when I ran across the OBM grinder and purchased that one. The reason I bought this motor was because I didn't have 220v service in my shed. I have since found info that says that a 3 phase motor can be powered using a VFD supplied with 110. Can someone explain this to me?

What is the best way to utilize this motor providing the ability to adjust belt speed, or should I just buy a better suited motor for use with a VFD?

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Thanks in advance!
 
Yes. I know the KBAC drives will let you use 115VAC single phase input and they will output 230VAC.

If this sounds too good to be true, it isn’t. It works fine, but you pay a small price in that you won’t get the full HP out. (Don’t worry- you’ll probably never feel the difference.)

I believe this is an option up to 1.5 or maybe 2HP. I’d have to check.
 
John Wilson said:
Yes. I know the KBAC drives will let you use 115VAC single phase input and they will output 230VAC.

If this sounds too good to be true, it isn’t. It works fine, but you pay a small price in that you won’t get the full HP out. (Don’t worry- you’ll probably never feel the difference.)

I believe this is an option up to 1.5 or maybe 2HP. I’d have to check.
Click to expand...

Well It looks like I will be selling a new, never used motor! After posting the original question, I've seen where I might be needing a RPM of 3600. Thoughts? Any ideas on some places where some of the least expensive ones can be found?

Thanks guys, I've been a member for a couple years (couple questions, mostly lurking!). Just changed my username. Before seeing a post where it could have been changed for me.
 
Wayne, above, sells everything you need.

The other places to browse and compare specs are

electric motor wholesale .com

automation direct .com
 
and yes- personally I’d go with a 3600 RPM model. make sure you get a 56C frame. 56 is the size of the motor’s frame. The “C” means it can be face-mounted as well as foot mounted.
 
John Wilson said:
and yes- personally I’d go with a 3600 RPM model. make sure you get a 56C frame. 56 is the size of the motor’s frame. The “C” means it can be face-mounted as well as foot mounted.
Click to expand...

Thanks John! I had everything right on the first motor, with the exception of the 3ph! After the motor comes in, I will have to figure out exactly how to mate the motor to the OBM grinder. Am I going to use a mandrel or attach the drive wheel directly to the motor shaft......... heck if I know at this point! I bought the motor Jan '17 in hopes of getting the grinder that was bought shortly thereafter going. Well the wife wanted to sell that house and build a new one on the water. Listed house and 9 days later under contract... Moved in to a rental with VERY LITTLE room and nowhere to chase this knife making craze. The grinder comes in after moving... My luck. Waiting on a shed to share with the wife's junk and maybe a little room for me, I hope to at least get the grinder going.
 
In order to run a 3 phase motor via 110vac, you want either a Kbac 27d, or you'll have to drop down to a 1 hp vfd. The Kbac will give you up to 1.5 hp on 110. You'll get a little more torque on the lower speeds if you go with an 1800 rpm motor and use the 2x speed jumper on the Kbac to get your 3600rpm. As for the drive wheel, it goes on the motor shaft. Make sure your motor has a base mount as not all c face motors necessarily have one. I believe the obm requires the base mount, if I'm not mistaken.
 
You can run the VFD on 115v power.
The VFD takes the 115v single phase power and converts it to 230v 3 phase.
There is no loss of power, it is running the motor on 230v power whether you input 115v or 230v
In the KBAC VFDs you can change a jumper to run the motor at double the rated speed. Inverter motors (such as I sell) are designed for this service.
I recommend using an 1800 rpm motor and changing the jumper.

Let me know if I can help you.

Wayne
 
Wayne, a question here because I've NEVER used the KBAC 27D drive, instead I use the cheap Chinese VFD drives. My question, does the KBAC 27D drive provide a full 2hp with 120 vac in? I've read if used with 120 vac input, it's max output is 1.5 hp, while with 230 vac input the max is 2 hp output. Please allow me to repeat, I do NOT know the answer and am looking for knowledge from you who has used many of those drives.

Ken h>
 
KenH said:
Wayne, a question here because I've NEVER used the KBAC 27D drive, instead I use the cheap Chinese VFD drives. My question, does the KBAC 27D drive provide a full 2hp with 120 vac in? I've read if used with 120 vac input, it's max output is 1.5 hp, while with 230 vac input the max is 2 hp output. Please allow me to repeat, I do NOT know the answer and am looking for knowledge from you who has used many of those drives.

Ken h>
Click to expand...

The KBAC-27d will NOT provide the full 2hp on 110VAC. It's maximum rating will be 1.5hp on only 110VAC. 230VAC will give you the full 2hp, though you could also run a 1.5hp motor with 230vac input. You'd just have to select the appropriate jumper for the built in overload protection to function properly.
 
You are correct Andrew - I'd never took time to chase the info in the manual since I didn't have that drive. I looked in the manual and found exactly what you say: "a. Model KBDA-27D – Has a maximum current rating of 6.7 Amps (2 HP (1.5 kW)) when used with a 208 – 230 Volt 50/60 Hz AC line input (factory setting of motor current and AC line input voltage). When used with 115 Volt 50/60 Hz AC line input (Jumper J1 installed in the “115V” position), the maximum rating of the drive is 5.5 Amps (1-1 ⁄2 HP (1.13 kW)). Be sure to reprogram Motor Current (Function No. 0.01) to the actual motor nameplate current rating (not to exceed 5.5 Amps)."
 
Yep. Nothing is free.

Most small HP 3ph input VFDs can run on single phase. Typically the output is derated by 20%. But the KBAC is the only one I know of that will run off 115VAC single phase. I’m not saying the others won’t, I’m just unaware of which ones will.

I had a pair of 230VAC Mitsubishi drives squirrelled away years ago. They were leftovers that I hung onto because 230VAC input is a rare bird in the industrial world. For the life of me I cannot figure out where I lost track of them. grrrrrr! I probably got tired of moving them over the years and tossed them.
 
Hello again all,

I am now in the steps pf mating a motor to my OBM grinder. I cannot find much, if any, information as to how to accomplish this! Do any of you have any videos or other assistance in helping me get this worked out?

Thanks!
 
John Wilson said:
Yes. I know the KBAC drives will let you use 115VAC single phase input and they will output 230VAC.

If this sounds too good to be true, it isn’t. It works fine, but you pay a small price in that you won’t get the full HP out. (Don’t worry- you’ll probably never feel the difference.)

I believe this is an option up to 1.5 or maybe 2HP. I’d have to check.
Click to expand...
I have exactly this setup. The 27D will allow you to run a 1.5 HP from 115v input. I have a 1.5 HP 1785 rpm motor running my grinder. Inside the 27D there is a 2x jumper that allows you to run the motor at twice the RPM. This puts me right around 3600 rpm WAO. Pair that with my bigger drive wheel and I can hawg steel when I need.
 
If I'm not mistaken you can also use a 2hp motor with the 27D on 115vac by derating the 2hp to 1.5hp. Just setup the 27D for a 1.5 hp motor and it's doubtful you'll ever bog the "1.5" hp motor down. The only thing the 25D knows is how much hp you're using, not what the max of motor is capable of. The only time you'd ever pull the full 2hp from motor would be running wide open with large drive wheel and hogging for all you got.

By derating the 2hp motor if you ever get 220vac you don't have to change motors.
 
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