Dayton Bench Grinder slow and hot

[macplee]

Got this bench grinder with stand the other day. It's a Dayton 3/4HP 8" grinder wired. It's wired for 220/440v. Model number is 4Z910C or 2LKT1 (according to Grainger's website).

Here's the problem. It's wired for 220V. I plugged it into my 220V 30amp outlet and flicked the switch on. At first it wouldn't turn, but no humping noise. I turned it off, then pinned the wheels by hand and confirmed they spin freely. Flicked it on again and it started spinning but at a very low speed and the housing was getting increasing and oddly very warm to the touch.

I have since dissembled it and see that the bearing are ok, but should probably be replaced. It still turns smoothy but looks a little dirty and a slightly rusty. I thought it must be a capacitor issue, but I was surprise to see this machine does not have a capacitor. The wiring is extremely simple and lots of wires. All are connected tightly and correctly according the owner's manual for 220v.

The only other thing I could think of is the switch. Grainger calls it a Toggle Switch 3-Phase as are charge $80 for it. Before I order the switch, I figured I would get some advice from you all. What do you think? See attached photos.

 

[mattthemuppet2]

it's a 3 phase motor and you're trying to run it from a 1 phase supply. You need to buy a 1hp 220>220V 3 phase VFD to run it. (or a RPC or a static phase converter)

 

[macplee]

Sorry, I am new to this. What I don't understand is that everything is original, and it matches the diagram of the owner's manual. The last photo is of the switch which indicates 3 phase. The original diagram shows nothing of a phase converter. Just trying to understand this better.

Mattthemup

it's a 3 phase motor and you're trying to run it from a 1 phase supply. You need to buy a 1hp 220>220V 3 phase VFD to run it. (or a RPC or a static phase converter)

 

[macplee]

Just looking into 3 phase vs. 1 phase motor. This is all new to me. May I ask what is the benefit of a 3 phase grinder? Or are there any considering the added cost of a VFD or converter to run it?

it's a 3 phase motor and you're trying to run it from a 1 phase supply. You need to buy a 1hp 220>220V 3 phase VFD to run it. (or a RPC or a static phase converter)

 

[mattthemuppet2]

that's right, it's simply a 3 phase AC motor and needs 3 phase AC to run. Some places (industrial typically) have 3 phase power so they just plug it into a socket. Residential homes have 1 phase power so you need to convert that 220V 1 phase to 220V 3 phase for the grinder to work. Couldn't tell you much about the pros vs. cons of 3 phase for a bench grinder, most likely it's that way because the people who bought it originally needed it to use 3 phase.

 

[Winegrower]

A static phase converter might be easier to hook up and maybe less expensive, haven't looked lately. Is there much call for changing rpm on a grinder?

 

[Kroll]

One benefits is most people don’t have 3phase nor mess with it.So that makes 3 phase machines,grinders cheaper than single phase since everyone has single phase power.If it were me I would purchase a vfd say a 1hp then if you should purchase something else that’s 3phase and 1hp or less you can use that vfd.Cost would be bout 150.00 and a converter maybe 600 or so.But if you look into future and foresee other 3 phase equipment in your shop the converter be better choice.

 

[Winegrower]

I think it is a bit problematic to use a VFD for multiple machines, since each VFD needs some customization for each motor. If you just want multiple 3 phase machines, I use a static phase converter, and plumb 3 phase through the shop. I use a VFD for my wood lathe, so I can change speed over a wider range than the basic machine.

 

[macplee]

I found this on Amazon. Looks pretty good and simple. A lot of the VFD simple overly complicated for what I need. I would like to control the speed and I would prefer to use a 110v input instead of a 220v. This unit allows for 110v in and 220v out with 3 phase. Anyone had experience with this unit?

 

[benmychree]

There would be scant benefit of having adjustable speed for a grinder, the smart money would be buying a static phase converter.