Belt grinder motor

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PandaRen

Joined
Apr 10, 2021
Messages
44
Hi all,

so I'm looking into putting together a belt grinder to have faster fun with knife making and since I'm not electrician and my knowledge is limited to what I can read right now (and of course, understand ) I'm asking for more help!

I'm looking at what's available around me and stumbled upon this for 100$:
173101021_3653003404827773_8099935630010074502_n.jpg

now I was wondering if the voltage would work with a KBAC-27D? Everything seems good with the motor except the 575volts... What's the verdict?

Thanks!
 
It won't work. What you would need to get it to work would cost you several times the cost of even a brand new 220V 3 phase motor that will work.
I'd keep looking.
 
Damn... ok thanks.

Would this one be a good find?
$_59.JPG
$_59.JPG

seems to fit the bill. For 150$CAD is it a decent deal?
 
That’s a good deal and will work. 1.5 hp is the minimum I would go on a grinder. I had a 1.0 on mine and was stalling it out, so I upgraded to 2 hp.
 
First one would work if it was 220v, but it was 575v, which is why it was so cheap! I was looking at used motors and when I saw a good one cheap, it was usually 430 or 575 v, not 220v! 2nd one looks good to go!
 
A very important parameter is the diameter and length of the shaft. Also if it is keyed or threaded. Many used motors might be difficult or expensive to match to a drive wheel. Assuming that you already have a drive wheel that you want to use. These are 3-phase motors and you might want to look up "inverter duty" ratings.
 
kbright said:
A very important parameter is the diameter and length of the shaft. Also if it is keyed or threaded. Many used motors might be difficult or expensive to match to a drive wheel. Assuming that you already have a drive wheel that you want to use. These are 3-phase motors and you might want to look up "inverter duty" ratings.
Click to expand...

It's a 56C frame, so shaft length and diameter are pretty standard across that frame size.

One thing I did just notice, however, is that it is only a Class B (referring to insulation) motor. Most "inverter duty" motors are a class F, if I recall correctly, meaning that the insulation can take a little bit more heat before it starts to break down. That doesn't mean that this motor won't work on a VFD, but it may last only 5 years instead of 10, or 10 instead of 20, depending on use and how hard it's ran.

OP: you may just want to keep an eye on motor temps during average use and just make sure that things aren't getting toasty. Also watch it when running at slower speeds, as that's when you have the highest propensity for overheating, as your fan isn't pushing as much air over the motor. If you do a lot of slower griding, you may want to set up a secondary fan to aid in cooling. As the name plate says, it's made to run at no higher than 40C continuously.
 
Drew Riley said:
It's a 56C frame, so shaft length and diameter are pretty standard across that frame size.

One thing I did just notice, however, is that it is only a Class B (referring to insulation) motor. Most "inverter duty" motors are a class F, if I recall correctly, meaning that the insulation can take a little bit more heat before it starts to break down. That doesn't mean that this motor won't work on a VFD, but it may last only 5 years instead of 10, or 10 instead of 20, depending on use and how hard it's ran.

OP: you may just want to keep an eye on motor temps during average use and just make sure that things aren't getting toasty. Also watch it when running at slower speeds, as that's when you have the highest propensity for overheating, as your fan isn't pushing as much air over the motor. If you do a lot of slower griding, you may want to set up a secondary fan to aid in cooling. As the name plate says, it's made to run at no higher than 40C continuously.
Click to expand...

Just to be clear, that Baldor motor is rated to be run at full speed continuously in 40˚C ambient conditions. That's wildly different from the internal temperature of the motor which will be far higher (and completely fine long term). All of Baldor's VM series motors are inverter rated down to 25% speed if I recall correctly. Class F insulation buys you more headroom but isn't necessary for a belt grinder application, especially one not used around the clock. All of the specs on the data sheet assume 24/7 operation at full power and a lifespan of ~20,000 hours. Most people's belt grinders won't see anywhere near that level of use so a quality Balder motor will last for the life of the grinder.
 
CallumRD1 said:
Just to be clear, that Baldor motor is rated to be run at full speed continuously in 40˚C ambient conditions. That's wildly different from the internal temperature of the motor which will be far higher (and completely fine long term). All of Baldor's VM series motors are inverter rated down to 25% speed if I recall correctly. Class F insulation buys you more headroom but isn't necessary for a belt grinder application, especially one not used around the clock. All of the specs on the data sheet assume 24/7 operation at full power and a lifespan of ~20,000 hours. Most people's belt grinders won't see anywhere near that level of use so a quality Balder motor will last for the life of the grinder.
Click to expand...

My mistake. You are correct about ambient temp, I misspoke. I was not aware of the 25% inverter speed rating. I've seen a pretty good number of lesser quality motors "cooked" over the years, but its was often a combination of ambient temps, motor loads, short cycling, and other things. Like you said though, 95% of knife makers probably aren't using their machines hard enough to make a difference on something like the motor in question.
 
Well thanks everyone for the input. Still waiting a bit and looking around now that I know more what to watch out for!
 
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