New toys: 1/4hp motor with VFD

As I'm leaving the office today one of the guys out in the production area said he set these aside for me (he knows I've been looking to motorize my mill with something other than a drill).

He says these should be plenty powerful enough to run my corona-style for now and a roller mill when I get one. He doesn't really know much about grain mills however and I thought I'd see what you guys think.

If it is usable, how would you suggest I couple the motor to the mill. He suggested bicycle cogs but I don't weld (and don't want anything permanent if avoidable) so something with a set screw would be more in line for me.



Here's the plate from the motor. The pair are already wired together so I don't need to try and mess with that fortunately.



Any help would be appreciated!

Is that a three phase motor? Assuming you have the line voltage to run it, the setup looks really nice. I like using belts and sheaves to couple my motor to the mill.

Here's an example of mine:

https://www.homebrewtalk.com/showthread.php?t=42598&highlight=crankandstein+table

All Princess Auto junk. I and mean that literally. I liked the belt idea because it can slip if the rollers jam. Well it jammed yesterday and belt started to slip, so I cranked down harder on the tension and it blew one of the couplings in half and shattered the bushing. sigh.

I'll be honest I have no idea. It's setup to run on 110V (he wired it up specifically for me). So I should be able to get some kind of pulley to mount on this and the mill?
I'll admit to total ignorance in this area, I'm just a computer guy.

Ah I see! There's actually a princess auto about 5 minutes from the office so I guess I'll need to make a trip. And I know what you mean about junk, my brother swears by that place but he's a cheap bugger.

I guess the inverter must take care of the voltage, because that plate looks to indicate 3 phase and at least 220 vac. But no matter, if it works its right.

You can get the pulleys (sheaves as they would be called in this case) and necessary bushings/spider couplings at PA. I'm not sure what you have coming out of your Corona, but you may need some pillow blocks and a coupling to keep tension off the shaft. I don't think I would direct couple the motor to the mill.

Do you know how slow you can run the motor?

The VFD goes by Hz and I can set it as low as 0.5Hz. It definitely moves at that speed, but you have to watch REALLY closely.

Looks like a good setup. 1710rpm at 60hz so you can get it nice and slow as desired. I don't really see a problem with no gear reduction. Even though he detuned it to 115, it still has enough torque to crush little barley husks. Now you get to sit back and enjoy the magical sounds of a VFD setup!

I must admit I liked the sound it made - almost none! Even at 60Hz when it was really flying it was very quiet.

Of course if I hook that up to my corona-style it'll make enough noise to wake the devil. :rockin:

For what it's worth Motorizing a Malt Mill

This applies specifically to the JPS Malt Mill, but should be pretty applicable to any grain mill. I'm not handy, so I have no idea how easy or difficult some of these things might be, but it is thorough article.

Chad

If you can run it under 150 rpm, I'd suggest using 3" sheaves on both ends. Looks like a really nice toy.

You're issues will be alignment if direct coupling to your mill, or how to adjust the tension if you go with belts. If you look at my link above, you can see how I dealt with the problem.

I can run it so slow you can't tell it's moving unless you stare for a few seconds. I'll go with the 3" sheaves on both ends to start out with. I can always play with it. I'm not too concerned about destroying my corona-style, it'll give me an excuse to buy a monster mill.

Chad: Fantastic link, thank you!

I picked up the pulleys and belt at Grainger Mines was also gear reduction so it was at the right RPM so I just needed the same size pulleys and a belt. Of course it was two different shaft sizes and one needed a set screw and one a keyway but grainger had everything.

SuperiorBrew said:

I picked up the pulleys and belt at Grainger Mines was also gear reduction so it was at the right RPM so I just needed the same size pulleys and a belt. Of course it was two different shaft sizes and one needed a set screw and one a keyway but grainger had everything.

Click to expand...

I think finding the parts I need will be the tough part now. The mill has a slightly tapered crank, it's not really made for taking a pulley. I have a screw with a lock-nut threaded into it now to run my drill, maybe I'll just use that.

If you put the motor on a hinged wooden plate you can use the weight of the motor to apply tension to the belt. If the plates should get stuck for some reason you can quickly take the tension off the belt by lifting the plate & motor and not smoke it.

As far as the bike cog idea, it would be a very simple setup as long as the end of the motor's spinning spindle(i'm not down with all the tech talk, sorry) could be drilled out so a screw would fit in it.

Basically you would need some washers that would slide on to that spindle, one bike cog, more washers on the other side, and the screw (or cap) that would tighten up on the cogs and washers to keep everything in place. Its the same way a single speed bike is setup on a bike that is ment for multiple gears.

But you would need to make it so that the bike cog turns as the motor turns of course which would be the difficult part if the motors spindle is does not have ridges to "lock" the bike cog in place.

The spindle just has one rectangular grove in it (I think they're called keyways but I'm not up on that stuff either).

Fingers: Nice idea, I think I will implement that.

Think about "gearing" it down a bit with a bigger pulley on the mill. Even though you can reduce the rpm with the controller, you'll get smoother, cooler operation by letting the motor wind up a bit and keeping the mill speed down. BTW grease that mill!! I use crisco vegetable shortening on mine. They just aren't designed to be motorized, and you could easily break that cast aluminum shaft, or friction weld it to the housing.

I did mine with love-joy couplers that I bought from mcmaster carr. As long as you can slow the motor down it would work fine. Plus its a lot less moving parts and what not. If you want pictures I'll post them or send a pm and I'll email them

Fingers said:

If you put the motor on a hinged wooden plate you can use the weight of the motor to apply tension to the belt. If the plates should get stuck for some reason you can quickly take the tension off the belt by lifting the plate & motor and not smoke it.

Click to expand...

Look at my link above for an example of this. I just use trigger type clamp to pull on the board to adjust the tension.

bradsul said:

I think finding the parts I need will be the tough part now. The mill has a slightly tapered crank, it's not really made for taking a pulley. I have a screw with a lock-nut threaded into it now to run my drill, maybe I'll just use that.

Click to expand...

How big is the shaft, and how good are you with a file?

mr x said:

How big is the shaft, and how good are you with a file?

Click to expand...

Pretty good, I've also got an angle grinder and a bench grinder so I could make pretty quick work of it.

I just got my christmas bonus though so I'm REALLY thinking hard about a monster mill instead of paying down some bills.

Wow, that's a nice score! And yes, that is a 3ph motor, but that's what the inverter is for.
If you have any farm-supply stores near you, they ought to be able to hook you up with some v-belts and pulleys in whatever configuration you need.

Go for the three roller model if you can. I love mine.

Bernie Brewer said:

Wow, that's a nice score! And yes, that is a 3ph motor, but that's what the inverter is for.
If you have any farm-supply stores near you, they ought to be able to hook you up with some v-belts and pulleys in whatever configuration you need.

Click to expand...

I've got a TSC store a few minutes away, I was wondering if they had might have those items. I'll have to hit them up, I'm really not a Princess Auto fan, cheap prices or not.

mr x said:

Go for the three roller model if you can. I love mine.

Click to expand...

Would this motor be strong enough to run a 3 roller mill?

The sheaves and belts at PA are ok for this kind of thing. The bronze bushings are very fragile, but that may be the case with bronze in general. I'd go for a harder metal bushing if available. As far as their couplings go, I snapped one of mine under a real heavy load, so take that for what it's worth. All though now that I think about, in the catalogue, they may have a rating on them I went over...

bradsul said:

Would this motor be strong enough to run a 3 roller mill?

Click to expand...

I would think so.

I'll take a look at the plate on my bodine and see what it says, but I'm thinking you'll have no problems there.

My motor is rated in Nm at 6.2 which is 4.57 ft/lbs. I'm not sure if this can be converted into hp.

mr x said:

My motor is rated in Nm at 6.2 which is 4.57 ft/lbs. I'm not sure if this can be converted into hp.

Click to expand...

Torque is only half the information needed to calculate mechanical horsepower....do you have the voltage and current ratings??? 1 horsepower = 746watts

I am curious to see what the torque curve looks like when you slow the motor down to the speed you would need and also to see if you have to derate the power produced by the motor such as when you use a static inverter. In the case of a staic inverter you derate by approximately 33%. I have little experience with a VFD inverter so I have no idea.

I would definitely use a larger sheave on the grinder and a smaller one on the motor to give it a mechanical advantage or see if you can pick up a small gear motor and use a lovejoy coupler.

Good luck with this project....

I mounted the motor on a plate so tight that I can't see all the info.
I'm thinking it was rated at 260 watts, but I can't be sure.

I'm thinking his motor will have no problems at 150 rpm without stepping up the sheaves.

I'm going to talk to the production guy at work tomorrow about the power curve of this motor. I know they use it for making feeding equipment so it runs continuously at slow speeds moving some pretty heavy stuff with feed screws etc.

mr x said:

I mounted the motor on a plate so tight that I can't see all the info.
I'm thinking it was rated at 260 watts, but I can't be sure.

I'm thinking his motor will have no problems at 150 rpm without stepping up the sheaves.

Click to expand...

Most likely it is a 1/3HP

This is a severe duty motor so it can take a pounding.....

Well I have been doing some research on motorizing grain mills since I know I will be in the same situation one day, hopefully soon.

Since I don't have a mill I have no idea of the torque needed but a couple sites I visited recommended a minimum of a 1/3HP motor using sheaves to reduce the rotation to 120RPM which would give you a pretty big mechanical advantage.

I am curious to find out if this will work.....

My monster mill has arrived! I wasn't expecting to receive it so soon given the time of year and the fact it was going through customs. I ordered Dec-9, it was shipped Dec-10 and I received Dec-20.

This is the MM-2 with the 1/2" drive shaft. Too bad I have to wait until January to build a milling station to go with it.

That's a beaut eh?