Wide belt sander on a VFD?

[Carl Beckett]

Ok - Im sure this is posted here somewhere...... a lot of good info on phase converters vs VFD.

Im looking at a used widebelt. Its 15Hp, 3 phase.

Practical to run on a VFD? (and at what cost - I see $900+ ish listed). Rotary phase converter? ($2k?)

Or maybe its just too dang big for my shop, and I should just keep the dual drum sander I have now......

I 'might' be able to swap the dual drum plus a small 13" belt sander out for an AEM 25" belt sander and VFD and come out a wash... (or maybe I dont have enough power period to run a 15hp machine, but thats another project all together)

Thoughts?

[Jim Neeley]

I know of two pros who have wide belt sanders w/VFDs on them in their shop. The second bought theirs at the recommendation of the first. Both love them because of the ability to slow them down when sanding burn-prone wood or plastics.

Third hand info but it's all I have.

[Peter Quinn]

15HP single phase to 15HP three phase with a VFD? Is that actually possible? IIR 5HP was about the upper limit of I could find that did conversion 220V single phase to three phase. No expert here but there seemed to be an upper limit on phase conversion with a VFD. So you may find a VFD for speed change that is 3 phase in three phase out, maybe not capable of phase conversion. Interesting if its possible though. My search was several years ago, things do change.

Huh, seems they do have drives for that, just found them in a quick search. One thing I like about rotary conversion for a circuit that large is that you can use it for other machines where the VFD is dedicated.

[David Kumm]

You can do it but I'd look for a used Phase Perfect- my 20 hp 64 amp was 2500. You can watch for a 70 amp input single phase as well. Used will likely be in the $1000 range. You need enough amps left over for the DC. Dave

[Stephen Cherry]

One option on drives is to do the rectifying and filtering outside of the drive. Digikey sells rectifiers, and filter capacitors. Basically, as an electrical engineer, I would try to find out what size filter caps and rectifiers are in the 30 hp drive, and "borrow" that information. Hitichi has the wiring diagrams on their site. Otherwise, you need to double the drive hp to do phase conversion-- 15 hp motor takes a 30 hp drive.

As for rpc, that could be scrounged for pretty cheap. Mine has a 15 hp idler, and for a 15 hp machine, maybe a 30 hp motor would be OK. Then you need a starter box with thermal overloads, and an extra contactor for the start capacitors. The practical machinist site has lots of info, as well as gurus. These types of things can be had at auctions sometimes for next to nothing. who's going to buy a motor starter box, of 30 hp motor?

[Brian Ross]

I have a 18 hp widebelt that I run on two rotary phase converters. Both are 20 hp. I originally had a 20 hp RPC and ran a slider and DC on that with lots of power and ran flawlessly for 5 years. I then bought the widebelt and due to the huge current draw on start up I needed a larger RPC. I bought my first from American Rotary and they advised that to keep them balanced I would have to purchase another 20 hp unit which I did. I run each RPC on a 60 amp breaker. American Rotary has been excellent to deal with and truly 24/7 service.I would suspect that you would need a 30 hp unit but I would check with American Rotary first.

Brian

[Rick Fisher]

I run a 12hp wide belt .. if memory serves, its maxed out at 31 amps 220V PH3 .. There is also a 1hp gear motor for the conveyor .. I can tell you that it does not draw that kind of power when running .. Its uncommon to see the ammeter break 20 amps .. I figure that is about 7.5 hp ..

It makes me laugh because my sander in Europe is sold with a 9hp motor .. In North America, its 12hp .. Felder will sell you a 37" twin belt with 15hp or 20hp.. Probably works okay ..

Oh.. anyway .. 15hp likely has an FLA of 38 - 40 amps .. Figure on needing 70 amps minimum of PH1 input ..

[Jim Andrew]

You didn't post the price on the sander, but I got the grizzly 9983 small widebelt sander, and the price is very good, has plenty of power with 5 hp single phase, belts are inexpensive, and for wide panels, I just turn around and run through the other direction. Skipped the drum sander route when I found the belt sander was a comparable price.

[Carl Beckett]

Oh - pricing is important. The belt sander will run $1000

My first thinking was that I could pick up the VFD for $500 - a completely viable upgrade, and would sell the drum sander and smaller wide belt and save space and have higher capability (I think the two of these priced out would get me about $1500 - but I could be wrong on that also)

BUT.... Im rethinking that decision because:

The larger HP means a more expensive VFD. Or RPC (will have to go out and scrounge for used). And for a VFD its more like $1000 than $500 - havent looked for the RPC yet (although once a do a large RPC - I can run anything on it which makes the used equipment market open up a bit)

As someone points out I will need as much as 70amp input to the single phase. I dont currently have that (but could - am doing an electrical upgrade at the same time so although it changes things its not a show stopper)

Its a project - and Im not 100% certain I want another project. But a wide belt sander has appeal, and if I can get into one for under $2k it seems like a worthwhile upgrade.....

(Jim - have been eyeing those smaller grizzlies for a while.... but they still arent 'cheap')

[Carl Beckett]

turns out I can pick up a STATIC phase converter for $180. Wouldnt give the full 15hp rating... but for $1280 I would have a functioning 25" wide belt.

deal or no deal?

[Stephen Cherry]

Before I put together my phase converter, I improvised one using a 30 amp breaker in the box, a 15 hp motor, a light switch, and some start capacitors. Basically, the single phase breaker was wired to two of the three legs of the motor, and the light switch selectively wired in the capacitors between the dead leg of the motor, and one of the powered legs.

The procedure, turn on the light switch, turn on the breaker, let the idler motor spin up, turn off the light switch, and voila (that's french), there's three phase power coming off of the three legs of the motor.

Another option is a pony motor- spin up the idler with another motor, turn on the juice, and there will be three phase power.

[Jim Andrew]

Is the sander locatated where you can give it a try before buying? You didn't mention freight, so assume it is close by. What a buy if it is in running condition. No, a new Grizzly won't compete with that. Just checked my catalog,a new 24" Griz is 8555. plus 255 freight. The small open end like I have is 3595, and 179 freight.

[Rick Fisher]

Well.. If its a 15hp drive motor, on a static it would produce about 10hp.. I would suggest that 10hp is more than ample so long as you don't abuse it .. If mine where 10hp instead of 12, I wouldn't care.. It seems to be a north american thing to buy a much bigger motor than you actually need.

[Carl Beckett]

Update:

This sander, along with a used phase a matic static converter, now resides in my workshop. It doesnt look too bad - with exception of one of the top rollers that may need a little work (am sure it works with just the other 3). Its been painted grey.

I wont be able to get it going for a few days - stay tuned. Some crappy pics (I dont know how to delete the attachment thumbnail....):

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