Grinder motor confusion

Ken, the speed range is now 180-3,600rpm and 6-120Hz. This now matches the turn down rating of 10:1. The top end speed was reduced from 4,000rpm to 3,600rpm. They also fixed the specs for another Leeson 2HP motor that had similar issues. That one is a bit cheaper and a tad shorter, but it only has a 2:1 turn down rating.
 
With the 7" drive wheel you ordered you'll have PLENTY of belt speed for sure at almost 6600 SFPM at 3600 rpm. That's going to be BLAZING fast. Sure hate for a 36 grit belt to break at that speed :) 180 rpm will give 330 SFPM which is a good slow speed.
 
Yeah, that is 75 mph, or about half the speed we go on the Autobahn:D. I plan to set the max speed much slower than that, at least to start with.
 
I received the motor today. Guess what, the drawing on the website is also wrong. The motor is a whole inch longer than what the drawing shows. I called them and the guy said it's probably longer now because of new efficiency standards. I don't know how that explains why they kept the old drawing on the website, but at least they offered to pay for return shipping and refund the money within 30 days. I'm not sure if I'm going to keep it or not, but I doubt I'll buy anything else from them in the future.
 
Yes, that's the one. I think I'm going to keep it and make the stand an inch taller so the longer motor has clearance.
 
volsr1 said:
I use an Ironhorse 1800 rpm, 1.5hp DC motor from Automation Direct (link below) on my Ameribrade grinder. I paired it with a DC motor controller (link below). I use a 7" drive wheel to get the speed I need. It operates on 110v AC. The torque from this motor is amazing, especially at slow speeds and the reverse feature on the controller comes in handy when I use my grinder as a sharpener (Reeder sharpening jig copy). The speed control is sealed but the wire terminal strip is exposed (not good for metal dust contamination). At the moment I have electrical tape covering the terminal but will probably drop it all in a sealed box eventually. KB also makes a DC speed controller that's in a NEMA enclosure, but it's a bit pricier. My whole motor/speed control combination only set me back $360.

https://www.automationdirect.com/ad...ors_(up_to_2hp)/general_purpose/mtpm-1p5-1l18

https://www.ebay.com/itm/120-VAC-To...:OiQAAOSwAmVck46n:sc:USPSPriority!38469!US!-1
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How has this set up been working out for you? Have you changed anything? Are you getting power surges when trying to control the motor at lower speeds? I am. I did exactly what you did and it works great at 100% rpm but below 90% I get power surges when the controller heats up. I think I’m drawing to much amperage from not having enough torque. I’m really curious how your setup is doing
 
Lieblad said:
In context of induction motors driven by VFDs.
I suppose its squirrel cage bars could be considered windings. But they are pretty much immune to centrifugal force.
I think overspeed mechanical limits/failure is more likely result of bearing failure or rotor balance.

Fwiw, Large series wound brushed motors. Windings or commutator can be damaged by overspeed. They must never be allowed to run without appropriate mechanical load. Otherwise they can spin up until it explodes. But if lucky a winding comes off first to shut itself down.
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He's not looking at a brushed motor. Don'e tconfuse him.
 
Piper2328 said:
How has this set up been working out for you? Have you changed anything? Are you getting power surges when trying to control the motor at lower speeds? I am. I did exactly what you did and it works great at 100% rpm but below 90% I get power surges when the controller heats up. I think I’m drawing to much amperage from not having enough torque. I’m really curious how your setup is doing
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It's working well. I've not had any surging issues. I run it 50% when sharpening. I do keep a fan blowing on my speed control because it gets pretty warm. I also use VSM 885 ceramic belts that don't require high speed to work well when I'm hogging material. I'm wondering if you have other things running off the same circuit.
 
Well that’s hopeful for me then. The only other thing I have running on that circuit is a small fan to cool the controller but I wasn’t always running that. I only started doing it when the surging started. Is you motor directly driving your drive wheel or do you have some sort of pulley system set up? Mine is a direct drive. I have a 8” drive wheel attached directly to the 1800 rpm motor.
volsr1 said:
It's working well. I've not had any surging issues. I run it 50% when sharpening. I do keep a fan blowing on my speed control because it gets pretty warm. I also use VSM 885 ceramic belts that don't require high speed to work well when I'm hogging material. I'm wondering if you have other things running off the same circuit.
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Well that’s hopeful for me then. The only other thing I have running on that circuit is a small fan to cool the controller but I wasn’t always running that. I only started doing it when the surging started. Is you motor directly driving your drive wheel or do you have some sort of pulley system set up? Mine is a direct drive. I have a 8” drive wheel attached directly to the 1800 rpm motor.

volsr1 said:
It's working well. I've not had any surging issues. I run it 50% when sharpening. I do keep a fan blowing on my speed control because it gets pretty warm. I also use VSM 885 ceramic belts that don't require high speed to work well when I'm hogging material. I'm wondering if you have other things running off the same circuit.
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I’m starting to wonder if something is wrong with my motor or controller. I bought them both brand new. I have been talking through eBay to the guy I bought the controller from and he’s telling me I need to have a 4to1 pulley ratio to increase torque and lower speed to stop the power surging I’m experiencing. Well if I did that I would have enough belt speed to grind my fingernails. I’m thinking my controller is faulty. What do you think?
volsr1 said:
It's working well. I've not had any surging issues. I run it 50% when sharpening. I do keep a fan blowing on my speed control because it gets pretty warm. I also use VSM 885 ceramic belts that don't require high speed to work well when I'm hogging material. I'm wondering if you have other things running off the same circuit.
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Mine is direct drive with a 7" drive wheel. I've heard of $60 treadmill speed controllers working just fine. I think the speed controller we have is basically a treadmill controller in an easier to use box. Could be the speed controller is the culprit.
 
thanks for the information buddy! I’ll talk with the guy I got the controller from and see if he’ll work with me on getting another one.
is there anyway you could text me a picture of your setup just so I can prove to this guy that it’s probably not the way I’m using it since your using it the same way and have had no problems.
volsr1 said:
Mine is direct drive with a 7" drive wheel. I've heard of $60 treadmill speed controllers working just fine. I think the speed controller we have is basically a treadmill controller in an easier to use box. Could be the speed controller is the culprit.
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Someone should think about starting a DYI belt grinder thread because I can't be the only one who is interested as hell on the subject and is planning on making one also. At this stage of the game I am currently using my belt sander clamped in a vice with a platten made from a street sign and a 2x4
 
Piper2328 said:
thanks for the information buddy! I’ll talk with the guy I got the controller from and see if he’ll work with me on getting another one.
is there anyway you could text me a picture of your setup just so I can prove to this guy that it’s probably not the way I’m using it since your using it the same way and have had no problems. My cell is 8649100640. I would greatly appreciate it
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Remind me in a week. I'm in Nashville waiting on the birth of a grandbaby. I should be home in a week or maybe a little longer
 
There are plenty of free 2x72 grinder plans online for the diy person. I built my own using a bolt together plan. No welds required since I don’t have a welder. It turned out pretty good.
Night Rider said:
Someone should think about starting a DYI belt grinder thread because I can't be the only one who is interested as hell on the subject and is planning on making one also. At this stage of the game I am currently using my belt sander clamped in a vice with a platten made from a street sign and a 2x4
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volsr1 said:
Remind me in a week. I'm in Nashville waiting on the birth of a grandbaby. I should be home in a week or maybe a little longer
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Hey man just wondering if you made it home yet and could send me a picture of your controller and motor set up? I am still getting the same results but worse out of the second controller that I’ve got from the guy on eBay. Him and I are wondering if you are using one of his older style controllers. If so he’s gonna send me one of those next to see if it works better with my motor. The second one he sent me got here today and it surges the power to the motor at all settings other than 100% rpm right away. It doesn’t even have to get warmed up like the old one. As soon as I plugged it in and started to increase the speed control it started surging and didn’t really stop until 100%! Crazy!!!if you could email me a picture or two I’d really appreciate it! Piper2328@yahoo.com
 
volsr1 said:
Remind me in a week. I'm in Nashville waiting on the birth of a grandbaby. I should be home in a week or maybe a little longer
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Congrats, found out this month 2 of my daughter in laws are pregnant. That'll make a total of 16 by the end of the year, nothing like grandchildren brother.
 
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