Which 3 HP motor for KMG?

Don Powell said:
Hi Troop,
I wanted variable speed on my KMG so I went with a reconditioned Allen Bradley variable frequency drive unit. Thank god I got variable speed, I don't think I could live without it.

My son designs conveyor systems, and he told me that used 3 phase motors are easy to find and very cheap. So I found a NEW 2 HP Baldor on eBay and it has worked fine. Note, if you will be full time, or use every day, you will need a motor rated for VFD use. My 2 HP is very, very strong, I can't see how I would have needed 3 HP. The motor is going strong for 2 plus years now.

I made a wooden enclosure with filters to protect the VFD from the metal dust. Also note, when using the VFD unit on 220v single phase ( like most all of us have in our homes ) the unit should be rated higher ( use 3HP unit for 2HP motor ), or check with the Mfg to be sure. Good luck, you will fall in love with the KMG!
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Thanks, Don. I've used a 2 HP Bader, and wasn't satisfied with the power. And since I'm spending the bucks anyway, I've decided to get a 3 HP. I don't want to get all excited about having this great new grinder, only to have it bog down when I really start to put it through the paces. (which I will do.) Talk about kicking myself in the ass!
Thanks for the info, but I'm still going to have to have someone be very specific and talk part #'s. I don't have a clue as to what to ask for if I call a supplier.
- Mitch
 
Ok Middletown electric is not there or unlisted...someone has to be listed nearest possible to you. You sound like you need a face to face encounter to get off the ground. There is alot of good advice in this thread so I would take some notes and look for someone amoung your friends, your parents friends, your bosses friends..maybe the guy at work who is an electrician or industrial maintainance. I have had a guy from work come over to put another outlet in my garage when i got statred in knifemaking. I crawled around up in the roof for the job so it was not alot of strain for him. We were both happy with the deal. Go to stores and shops and look for a referral.. You are so close to getting going its not funny if you just take some action of any kind and stop over thinking this : yes you are gonna need soemone who knows about this field which is out of our field. And when your place doesn't burn down or your motor not blow out because it was done right you can sleep good at night. Have lots of fun! :D
 
ssunfish said:
Ok Middletown electric is not there or unlisted...someone has to be listed nearest possible to you. You sound like you need a face to face encounter to get off the ground. There is alot of good advice in this thread so I would take some notes and look for someone amoung your friends, your parents friends, your bosses friends..maybe the guy at work who is an electrician or industrial maintainance. I have had a guy from work come over to put another outlet in my garage when i got statred in knifemaking. I crawled around up in the roof for the job so it was not alot of strain for him. We were both happy with the deal. Go to stores and shops and look for a referral.. You are so close to getting going its not funny if you just take some action of any kind and stop over thinking this : yes you are gonna need soemone who knows about this field which is out of our field. And when your place doesn't burn down or your motor not blow out because it was done right you can sleep good at night. Have lots of fun! :D
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Sound advice. Thank you. But, I have no such resources that are readily available. My fun is going to start once I fire up that bad boy! :D
 
fitzo said:
Those are really good prices, Luke. Care to share a source/link? Thanks!
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Well I would probably source stuff locally here in oregon, but http://www.dealerselectric.com/ mentioned earlier has a 3hp vfd for $275, http://www.driveswarehouse.com has one for $265 plus a 3450 rpm tefc baldor for $305. You can find generic motors for a bit cheaper, or you can gamble on ebay. I find that 3 phase motors are pretty common and cheap and it's easy to find them in new condition for way below the list price, especially near an industrial center like chicago.
 
Thanks for the info! One thing that made the controllers sound like a steal is the open enclosure, as opposed to the NEMA 4 or 12 that is all I've looked at. The motor is an excellent value. The drives would be great in a low-dust area, or could be located away from the grinder I suppose.

Thanks, again, Luke.
 
O.K., guys. This is what is sinking-in so far as to what I need:
- a three-phase, AC 220volt, 3 HP motor
- a NEMA 4 controller.
- duct tape, super glue, plenty of homeowners insurance. :D
Am I good, so far?
- Thanks again
- Mitch
 
I purchased a reliance electric 3 phase 3/4hp 1800rpm motor from Grizzly, and a TECO FM50 VFD from dealerselectric. this was for my homemade disc grinder.
Ignore the pics of the motors there, that is like a 10hp crusher motor in the pic.
here is the price for a 3hp in 1800
http://www.grizzly.com/outlet/G6244
3600
http://www.grizzly.com/outlet/G6245

I opted for the NEMA 4 enclosure for my VFD cause I did not want to build an extra enclosure to keep out metal dust. The NEMA 1 enclosures are cheaper if you do not mind building a dust box around it.

When I get the VFD and motor for my new belt grinder I will be getting that combo.
 
I have a new--though scuffed from shipping to me--Baldor variable speed motor. It is just about the same one as on Ed Caffrey's site. I will be back in CA around Christmas and will sell it for $300 plus shipping and handling from 95060.

It's one of these two, though I don't remember which:

http://www.baldor.com/products/deta...ly=General+Purpose|vw_DCMotors_GeneralPurpose

http://www.baldor.com/products/deta...ly=General+Purpose|vw_DCMotors_GeneralPurpose

If anyone is serious, email me at johnfrankl@yahoo.com and I will get you the EXACT info off the motor itself. It is stored in my brothers garage in CA and he can get the info for me if I need it.

Best,

John
 
gixxer said:
I purchased a reliance electric 3 phase 3/4hp 1800rpm motor from Grizzly, and a TECO FM50 VFD from dealerselectric. this was for my homemade disc grinder.
Ignore the pics of the motors there, that is like a 10hp crusher motor in the pic.
here is the price for a 3hp in 1800
http://www.grizzly.com/outlet/G6244
3600
http://www.grizzly.com/outlet/G6245

I opted for the NEMA 4 enclosure for my VFD cause I did not want to build an extra enclosure to keep out metal dust. The NEMA 1 enclosures are cheaper if you do not mind building a dust box around it.

When I get the VFD and motor for my new belt grinder I will be getting that combo.
Click to expand...

Wow, those are real good prices on those motors! But, for a variable speed grinder, do I need a DC or AC motor?
Thanks!
- Mitch
 
Mitch

It is possible to have control over the speed of both DC motors and 3-phase AC motors. It is not possible to control the speed of a single-phase AC motor in the hp range that you are interested in for a grinder.

For the DC motor, you need a DC motor controller. Use the search function to find leads on suppliers and info on how to choose one. They convert your single-phase AC input to a DC voltage for your motor. You vary the DC voltage to vary the speed of the motor.

For 3-phase AC motors, you will need a Variable Speed Drive (VSD). they are also known in industry as Adjustable Speed Drives (ASD) or just "drives". The VSDs convert the AC input to DC internally then convert it back to AC but a a frequency of your choosing. The speed of a 3-phase motor follows the input frequency up to overload. The big advantage of AC drive/motor combinations over DC is that you get full rated torque over the whole speed range. Again, use the search function since there has been much discussion on this topic. Some are designed to work with single-phase inputs without derating the output power so check the specs carefully before putting your money down.

The choice between AC and DC is up to you and may depend largely on what deals you find.

With all drives, AC and DC, make sure that you keep them away from the grinding dust or they will blow up, sooner or later. Getting one with a NEMA 4 or IP54 rated enclusure will help but it is still a good idea to keep them away from the grinding dust.

Got to run, the house painters are here.

Phil
 
pso said:
Mitch

It is possible to have control over the speed of both DC motors and 3-phase AC motors. It is not possible to control the speed of a single-phase AC motor in the hp range that you are interested in for a grinder.

For the DC motor, you need a DC motor controller. Use the search function to find leads on suppliers and info on how to choose one. They convert your single-phase AC input to a DC voltage for your motor. You vary the DC voltage to vary the speed of the motor.

For 3-phase AC motors, you will need a Variable Speed Drive (VSD). they are also known in industry as Adjustable Speed Drives (ASD) or just "drives". The VSDs convert the AC input to DC internally then convert it back to AC but a a frequency of your choosing. The speed of a 3-phase motor follows the input frequency up to overload. The big advantage of AC drive/motor combinations over DC is that you get full rated torque over the whole speed range. Again, use the search function since there has been much discussion on this topic. Some are designed to work with single-phase inputs without derating the output power so check the specs carefully before putting your money down.

The choice between AC and DC is up to you and may depend largely on what deals you find.

With all drives, AC and DC, make sure that you keep them away from the grinding dust or they will blow up, sooner or later. Getting one with a NEMA 4 or IP54 rated enclusure will help but it is still a good idea to keep them away from the grinding dust.

Got to run, the house painters are here.

Phil
Click to expand...

Thanks for the lesson, Phil!
Appreciate it, brother. Good luck with the painters.
- Mitch
 
pso said:
Mitch

It is possible to have control over the speed of both DC motors and 3-phase AC motors. It is not possible to control the speed of a single-phase AC motor in the hp range that you are interested in for a grinder.

For the DC motor, you need a DC motor controller. Use the search function to find leads on suppliers and info on how to choose one. They convert your single-phase AC input to a DC voltage for your motor. You vary the DC voltage to vary the speed of the motor.

For 3-phase AC motors, you will need a Variable Speed Drive (VSD). they are also known in industry as Adjustable Speed Drives (ASD) or just "drives". The VSDs convert the AC input to DC internally then convert it back to AC but a a frequency of your choosing. The speed of a 3-phase motor follows the input frequency up to overload. The big advantage of AC drive/motor combinations over DC is that you get full rated torque over the whole speed range. Again, use the search function since there has been much discussion on this topic. Some are designed to work with single-phase inputs without derating the output power so check the specs carefully before putting your money down.

The choice between AC and DC is up to you and may depend largely on what deals you find.

With all drives, AC and DC, make sure that you keep them away from the grinding dust or they will blow up, sooner or later. Getting one with a NEMA 4 or IP54 rated enclusure will help but it is still a good idea to keep them away from the grinding dust.

Got to run, the house painters are here.

Phil
Click to expand...

Read this one again:)

Have you talked to Rob Fink about a motor? I just bought a KMG and a 2HP with VFD controller from Rob. He said he had trouble coming up with a good VFD comb over 2HP. I wanted variable, so I went with what Rob recommended. If this 2HP VFD doesn't have enough power for me, I will sell it or use is on something else and get a 5HP Leeson and set it up with a set of 3 speed step pullys.

I have two BIIIs with 1-1/2HP DC, w/vaiable controlers. These have enough power for most of what I do but not enough for flat grinding big wide blades.
 
Don Hanson III said:
Read this one again:)

Have you talked to Rob Fink about a motor? I just bought a KMG and a 2HP with VFD controller from Rob. He said he had trouble coming up with a good VFD comb over 2HP. I wanted variable, so I went with what Rob recommended. If this 2HP VFD doesn't have enough power for me, I will sell it or use is on something else and get a 5HP Leeson and set it up with a set of 3 speed step pullys.

I have two BIIIs with 1-1/2HP DC, w/vaiable controlers. These have enough power for most of what I do but not enough for flat grinding big wide blades.
Click to expand...

Thanks, Don. I sent Rob an email this morning; no reply yet. That's what I plan on doing, mostly, flat grinding big, wide blades. Wow...a 5 hp is a lot of grinder! I've briefly used a 5 hp space saver, and that thing can definitely be classified as "for industrial use"!
 
Don Hanson III said:
Read this one again:)

Have you talked to Rob Fink about a motor? I just bought a KMG and a 2HP with VFD controller from Rob. He said he had trouble coming up with a good VFD comb over 2HP. I wanted variable, so I went with what Rob recommended. If this 2HP VFD doesn't have enough power for me, I will sell it or use is on something else and get a 5HP Leeson and set it up with a set of 3 speed step pullys.

I have two BIIIs with 1-1/2HP DC, w/vaiable controlers. These have enough power for most of what I do but not enough for flat grinding big wide blades.
Click to expand...

I bought the 1 1/2 hp VS KMG because I did not have a 220 volt tap for the 2 hp. It will bog a bit on big blades, but mostly when running at low speeds. At 70% with coarse grit zirconia belts, it hums right along even on larger blades. I think that the rotary platen that I just ordered may solve some of the bogging problems in addition to eliminating splice bump and belt bunching on finer grit belts.
 
Gotta go stack firewood... be back later.
Thanks for all your replies; you guys are helping me out big time!
- Mitch
 
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