Phase converter or new motor?

Wulf

Wulf

Joined
May 10, 2000
Messages
3,351
I recently scored a big old grinder - a clunky, unwieldy 2 x 132" machine. Could be a nice hogger to use for profiling blades, knocking off scale, that sort of thing...

This machine was well used, had been repainted, and the seller didn't know what it was (heck, neither did I when I bought the thing - the identifying labels had all been painted over). So I did some research, found it what it was (a Hammond UBG-132 - link), and learned that the machine, with the closed belt guard option, retails for some $5,930 new. In retrospect, I feel that my price of $330 was probably pretty fair. :D

Anyway, the machine needs a little cleaning and refurbishing before I crank it up, and I haven't yet decided what to do with the motor.

Currently, it has a 3-phase Baldor (208-230/460 V, 2HP, 145T frame). Since I only have 230 V single phase in my shop, I'm wondering whether to buy a phase converter or just outfit the machine with a new single phase motor.

I know next to nothing about electricity, wiring, and motors, but I really want to get this machine running. What should I do?
 
If your just going to make a hogger. Go to the junkyard and get a single phase motor. I picked up a 1.5 hp sigle phase motor with a Browning gearhead for $25. Ive got an old 2 x 132 homemade grinder that kicked some metal butt.

Mark
 
Whenever I buy an old machine to refurb, I ALWAYS replace the motor with single-phase. The newer 1-ph motors are way more efficient than the old ones. Try to get a totally enclosed motor to save it from the grinding dust, which will eat it alive. The style you'll be looking for is TEFC.
 
Gouge - I think I remember seeing some pics of that grinder that you posted once. Looks awesome! The one downside is that 132" belts are a little harder to come by, but I did find a box of about 20 in assorted grits on eBay not long ago that I was able to buy for about $20.

Steve, Jeff, when confronted with options, I tend to lean towards what I know, or what is simpler. So right now I'm thinking a single phase would be the way to go. That is, unless someone offers me a compelling reason to try something else.

If I do look for a single phase, will I be able to find one where the bolt holes line up with the existing holes on the machine? I'd hate to re-drill if I could avoid it...
 
Originally posted by Wulf

If I do look for a single phase, will I be able to find one where the bolt holes line up with the existing holes on the machine? I'd hate to re-drill if I could avoid it...
Click to expand...

If you get one with the same base as what you have now, it will.
The # 145T specifies the bolt pattern.
If you have to buy a motor with a different frame, say 56, you can get adapter plates from a motor manufacturer/distributor etc., if you don't want to drill new mounting holes.

Another thing to watch out for is the shaft size. It tends to change diameter with the mounting/frame size.
56 is usually 5/8", 145T is 1"(?)etc, etc. :eek:

BTW, nice buy. I hope it works out for you. There are a few makers that use 132" machines. Good luck.:D
 
Thanks Mike.

The shaft on this motor is 7/8". I'll start diggin' around a bit...
 
Wulf

Here are my $0.02 worth on AC drives. Please note that I used to work designing AC drives, but did not sell, install or program them, so I am not familliar with all the models and features on the market. My current employer, Toshiba, also makes AC drives, but I work in a different division and would derive no financial advantage from someone buying a Toshiba drive.

There are a number of AC drives on the market that will take single phase, 230V input and give you a 3-phase, 230V output. There are also a small number of drives that will take single-phase, 110V input and give you a 3-phase, 230V output. The output power of the 110V input drives are limited to 1hp by the 15A maximum current from a typical 110V circuit. Single-phase motors are about 60-65% efficient whereas the 3-phase motors are over 80% efficient. This may make a difference in your utility bills if your grinder is going all day long, every day. Please note that there are NO single-phase output AC drives that have enough output capacity for any sort of power tools. Single phase motors have a centrifugal switch to disconnect the starting capacitor. The motor must run at near its full rated speed for the centrifugal switch to work.

I had posted a survey showing some of the available drives about a year ago. Most of these drives will be more expensive than the simple units that one picks up off E-Bay, with no enclosure since they are meant for industrial applications and have features such as remote speed control, reversing, current limiting and braking functions. I have used a drill press equiped with one of these drives. It started really smoothly, the speed was infinitely adjustable, it would stop immediately, and if the machine jammed, it shut off the power immediately.

The list price for some appropriate drives from Toshiba would be in the order of $450-$550. Our sales guy admitted that Toshiba drives are not the cheapest on the market. He did say that if several people got together and ordered several drives from a distributor, the price would likely be discounted. He also suggested asking the distributor to inquire about obsolete models that the manufacturer may have in stock. Old Toshiba models would go for something in the range of $200. That would probably be a better deal than getting a used one off E-Bay since you would at least get a manual. My comments about group buying and buying obsolete models should be applicable to other brands of drives too.

One other potential source for inexpensive drives is to call around to some of the electrical distributors or contractors who sell and install drives. You may catch one where they are upgrading some factory with new drives, often for the new software features that have become available in the last few years. They may be willing to let you have one of the old units that they remove for, say $50, since they would usually just throw them in the trash. Just don't get one out of a cat food plant since it will STINK really bad :eek: :barf: !

Oh yes, if you are buying/acquiring a motor to go with an AC drive, it is preferable to get one that is "inverter rated". The AC drives put out a lot of high-frequency pulses that stresses the insulation in the motor, causing it to break down. It is possible to get away with a normal motor for years so if you already have one, use it. I don't think the inverter rated motors are really much more money though.

Hope that helps.

Phil
 
Thanks for sharing that info with us, Phil. I'm running 110V single-phase at home so my choices were limited in buying an AC drive or motor. I bought a 1.5 HP, 110V single-phase TEFC Leeson before I heard about people using a phase converter and 3-phase 230V motors.

Originally posted by pso
Single-phase motors are about 60-65% efficient whereas the 3-phase motors are over 80% efficient. This may make a difference in your utility bills if your grinder is going all day long, every day.
Click to expand...

The Leeson Wattsaver motor I got gets 84% full-load efficiency and draws 13 full-load amps with 115V input. It drops to 71.4% efficiency at 25% of full-load. The non-Wattsaver version is 79% efficient IIRC and draws more than 15 amps at full-load, so I got the more expensive Wattsaver. Both are inverter rated. The nice thing is that if I decide to upgrade my electrical line to 230V, I can draw half as many amps and save some $$$.

Originally posted by pso
Please note that there are NO single-phase output AC drives that have enough output capacity for any sort of power tools. Single phase motors have a centrifugal switch to disconnect the starting capacitor. The motor must run at near its full rated speed for the centrifugal switch to work.
Click to expand...

Now this has got me worried a bit. My motor is capacitor-start capacitor-run, so it may work differently :confused:. Edited to add: Phil is right here; I'm just confused because I'm not using an AC drive with my motor right now.

Wulf, I think a 1.5 or 2 HP single-phase motor at 230V would be great for you. Not too hard to wire up, either. Leeson makes both with 145T frame, TEFC. Standard NEMA 145T frame shaft is 7/8", so no worries there. Just my $0.02 :D
 
Hello SteelDriver

It sounds like your motor is of exceptionally good design and manufacturing quality. Don't worry about the lower efficiency at lower load levels. The input power will be only a bit more than one quarter of input power at full load.

A big "Whoops" on my part regarding your cap start, cap run motor. My comment was maybe a bit too general about there being no single-phase motors that can work with AC drives. I am not familiar with Leeson products but it is possible that they have designed a single-phase motor that will work with a drive of some sort, most likely a matching one. If your setup is working for you now, then don't worry about it and keep using it.


Mike

The package from Dealers Industrial Equipment sounds like a good deal. I looked under "Inverter Drives" on their web site and noticed that they sell some factory refurbished units. The control panel on the 20hp refurbished unit looks the same as that on the new units so it is likely to be one that was returned due to an ordering error and is likely to be unused. This particular unit is rated at 20hp and is meant to be connected to a 460V, 3-phase supply so it would not be appropriate but do ask or keep your eye out for more appropriate refurbished units. They also sell new, new but shop-worn and used motors. A new Reliance 1hp, TEFC would sell for $75 + shipping. A used one (not rebuilt) would sell for $35 + shipping. Do check the shipping costs first since the shipping for the used motor might cost as much as the motor itself. You may save some $ if you get a used motor locally, depending on your state taxes.

Phil
 
Phil, I reread my post and realized that somehow I was getting AC drives and motors mixed up in my head :footinmou. I think you're right that no single-phase output AC drives are used to run power tools. Like you said, it could be possible that Leeson designed a matching drive-motor package that runs single-phase, but I only have the motor. Sorry if I misled anybody, and I didn't mean to boast about my motor. I just wanted people to know that single-phase motors can be pretty good, too :cool: .

Mike, that's a nice price on a VFD package! I'll have to live with step pulleys for a a while though, to keep the KMG fund afloat :D .
 
Originally posted by pso
Mike

The package from Dealers Industrial Equipment sounds like a good deal. I looked under "Inverter Drives" on their web site and noticed that they sell some factory refurbished units. The control panel on the 20hp refurbished unit looks the same as that on the new units so it is likely to be one that was returned due to an ordering error and is likely to be unused. This particular unit is rated at 20hp and is meant to be connected to a 460V, 3-phase supply so it would not be appropriate but do ask or keep your eye out for more appropriate refurbished units. They also sell new, new but shop-worn and used motors. A new Reliance 1hp, TEFC would sell for $75 + shipping. A used one (not rebuilt) would sell for $35 + shipping. Do check the shipping costs first since the shipping for the used motor might cost as much as the motor itself. You may save some $ if you get a used motor locally, depending on your state taxes.

Phil
Click to expand...


I'm just talking about the special they have on the front page of the link. I don't know anything about rebuilt 20HP units???
Several makers have gone with the 1 HP setup @ $290, and 2HP @ $385 from dealers, and been very happy with them. All new stuff.:)
 
Actually the best way is to go "all-natural drive". One time I got a couple hamsters and sprinkled some cocaine on their lettuce then made them run on their wheel.. I figure if I get 1800 rpm off that wheel, I can get some sweet hogging action going when I grind. The only drawback is buying the coke. I tried to use caffiene once. The coffee I was using apparently wasn't up to par with those blasted rodents. Their tastes were obviously elevated - they only would take Starbucks! Well, I couldn't afford that, either, so I switched back to electrically-driven grinders.
 
You must log in or register to reply here.
Back
Top