Which Baldor motor to buy?

The main difference is that one is a face-mount and the other is not.

You don't say which grinder you are buying. If you are buying one that face-mounts onto the motor, you'll need the face mount (3611). If you are buying a grinder that just uses a foot-mount motor, either will get the job done, since the one with the face-mount also has feet.

The 182 frame (182C for the face mount version) is bigger than the commonly-used 56-frame (56C with the face-mount). Is the grinder you are intending to buy compatible with the bigger unit, particularly the 1 1/8" shaft size?

The Lenze drive you mention is an unswitched drive: no "real" start & stop buttons or speed control knob on the front panel (though they look to be available as an option). Running the drive from the keypad gets tedious very quickly. You will want proper buttons/switches and a pot somewhere you can easily reach them.
 
The 182 frame size it what stands out most to me. That's a huge shaft and a pretty bulky frame besides. MOST 2x72 grinders now days use a 56 frame motor with a 5/8" shaft, and most hubs, wheels, pulleys, etc... that are sold for knife grinders will have a 5/8" bore.

As for the drive, there are better options if you don't already have the Lenze, but most drives will have an option for an auxiliary analog control like a start/stop/reverse switch and a speed pot. I'd look into setting that up asap.

If you fill out your profile and tell us what kind of grinder you're buying, we may be able to give you some much better and specific suggestions.
 
knife to a gunfight said:
The 182 frame size it what stands out most to me. That's a huge shaft and a pretty bulky frame besides. MOST 2x72 grinders now days use a 56 frame motor with a 5/8" shaft, and most hubs, wheels, pulleys, etc... that are sold for knife grinders will have a 5/8" bore.

As for the drive, there are better options if you don't already have the Lenze, but most drives will have an option for an auxiliary analog control like a start/stop/reverse switch and a speed pot. I'd look into setting that up asap.

If you fill out your profile and tell us what kind of grinder you're buying, we may be able to give you some much better and specific suggestions.
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Yes.

Why are you stuck on 3 HP ?

2 HP and you will be MUCH cheaper, smaller, lighter, more parts options, made to fit the grinders
 
12345678910 said:
Yes.

Why are you stuck on 3 HP ?

2 HP and you will be MUCH cheaper, smaller, lighter, more parts options, made to fit the grinders
Click to expand...

Good point. Abokhaled17, if you already have the 3hp Lenze vfd, you can run a 2hp motor on it without any issue. There may even be a switch, jumper, or parameter to select a motor size less than 3hp, for circuit protection and what not. I'm not too familiar with the Lenze vfd, so I can't say how it's set up.

As for the decrease in HP, I know I've seen a lot of makers suggest up to 3hp, as it will NEVER EVER bog down NO MATTER WHAT, but in practice, I've never had an issue with 2hp. Even 1.5 is enough for most people. Less hp means a cheaper electric bill too... ;)
 
Thanks for the help everyone.
The grinder I'm getting is KMG so I'll have to use pulleys and a v-belt to connect the drive wheel to the motor shaft.
I think I'll use two 3" pulleys, one with a 3/4" bore for the kmg drive wheel and the other with 1.25" bore for the motor.
As for the VFD I only picked the Lenze because I was told it performs better than the kbac and baldor VFDs.
 
abokhaled17 said:
Thanks for the help everyone.
The grinder I'm getting is KMG so I'll have to use pulleys and a v-belt to connect the drive wheel to the motor shaft.
I think I'll use two 3" pulleys, one with a 3/4" bore for the kmg drive wheel and the other with 1.25" bore for the motor.
As for the VFD I only picked the Lenze because I was told it performs better than the kbac and baldor VFDs.
Click to expand...

Do you already have the Lenze? Who told you it performed better? I don't have any experience with the Lenze, but I can't imagine it's any better than the KBAC drives for a grinder application. The KBAC drives have pretty much become the industry standard for grinders, due to their NEMA4x enclosure (which your lenze has) and their simple and accessible controls. The price is quite a bit less as well, but either drive will work at the end of the day. As stated, you'll likely want to add an auxiliary speed control potentiometer for quicker adjustments if possible.

I'm still not clear why you're set on a 1.25" motor shaft. A 5/8" with a 56 frame will be plenty big enough for this application. That said, either motor you listed should technically work as well.
Just an FYI though, if you're going to be using the KMG on their factory base plate, it is designed to fit a 56 frame motor base and dimensions. The larger 182 frame will likely have to be moved a bit, and new holes drill and tapped. Shouldn't be more than an inch or two if I'm not mistaken, but still....
 
There is all sorts of conflicting information all over the web, and that's likely why the assumption is being made to jump to 3hp for a grinder. There's no reason not to, if you've got the money, I guess, but it likely a function of grinding style which determines requirements like this.

For myself, I'm not sure I can justify 3hp. That's not to say I wouldn't appreciate it, if I had it, I guess, but my direct drive KMG is currently using a 2hp motor, a 5.5" drive wheel, and is frequency doubled in the VFD for a top speed just shy of 5,000 sfpm.

The only time I'm using anything approaching the top end of this speed range is when I'm pulling off lots of material using coarse, ceramic belts. These belts prefer high speed to continue to fracture and create fresh, sharp abrasive. As per the engineer I queried at Norton Abrasives:

Hello Matt,
Thank you for your email. We typically recommend speeds based on the material you are grinding, when concerning a belt. For steel (all types), the suggested range is 4000-5000 sfpm. You can get a more aggressive cut by using a harder, more aggressive contact wheel, increasing your belt tension, running the belt slower, or going coarser on the grit. You can get a finer finish by letting up on the tension, using softer contact wheels, or increasing your belt speed.

I hope this helps!

For me, 2hp is more than adequate, as I freehand grind, and don't believe I'm physically strong enough to tax the grinder to the point of challenging its output before I'm risking a lack of control in my grinding, and perhaps even risking my own safety.


Like Drew, I'm questioning who told you your considered VFD is superior to others, especially Genesis/KBAC products. I've never heard anyone say anything like this before.
 
Good info here

2 Hp will save you about $1,000


I like the KB drives
I like the discrete switches, knobs and buttons.

Pressing up and down arrows a dozen times is a pita compared to twisting a knob.


I've seen some forgers who grind a billet or big bowie blade full length to flatten or remove scale say they like 3 HP
"Time is money " is their moto.

But as has been said, it's based on their particular style and is uncommon.



My first grinder came with 1 HP and I've never bogged that one down.
 
12345678910 said:
My first grinder came with 1 HP and I've never bogged that one down.
Click to expand...


So did my Wilton, and with an 11" drive wheel - can't remember if I managed to bog that or not, but I guess that kind of answers it, doesn't it? I'm sure I could, but what the heck would I be doing when I did?
 
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