Phase converters...

[Bob Brandl]

Hello, all. I have recently purchased a Beaudry #11 from a gentleman, and now have to figure out how to get it hereunder in my shop. Biggest thing, though, is that I have to get a phase converter for the beast. I'm looking at a 15hp rotary, but haven't any idea what brands to avoid, look into. Never messed with one, but know enough to know that I'm dangerous. Any suggestions? Thanks, everyone!

[7A749]

How many horsepower is the motor? Can it be wired for low voltage?  (I'm assuming you have 230 VAC available or wouldn't likely need a converter). Hopefully so. It's gonna draw some amps on start up I imagine. You can go about it a couple of ways. I have been using static converters to run my mill and lathe for the last 15 years collectively. My lathe is a Monarch Model 61 with a 7 HP three phase motor in it. I purchased a heavy duty Phase O Matic for it when I bought it 11 years ago. I have never had any issues with stalling it out or not having enough power. I'm not a VFD guy, but they do have their uses. 

As far as a rotary goes, you can go a couple routes. Personally, I think you would probably get the best results running a rotary, or a balanced setup with inverter drive but frankly, for powering a simple motor such as this, a rotary converter would suit the task fine and provide steady three phase current to it all the time versus a static converter which only uses a fabricated three phase output to start the motor. Once it's running, it's only running on single phase, hence the reduction in horsepower that's common with such devices. You might likely need a starter motor to get it turning over before engaging the static converter if you were to go that route. Increased expense there. Either way, you're gonna have some draw on start up.

I built my 15 HP rotary from an old Buffington phase converter I got in a trade a few years ago. For my uses (powering and testing three phase welding machines) I installed two different recepticle sand a 600 amp contactor to turn the current on and off to one of the outlets. It works very well, although I do have a high leg that runs about 40 volts over the others when at idle. It balances once under load tho. You can buy what is more or less a glorified static converter kit from places like WNY Converter on eBay and install it on your own power motor, which would then connect to the machine just as a standard three phase service would. I've found their prices to be better than just about everyone else online. I bought one of their static converters for my cold saw and it worked great until the motor puked. American Rotary is a good outfit too. Very nice and helpful on the phone.

Building or modifying an existing one would probably be the cheapest route to go. Check on Craigslist, you may get lucky and find one locally. I would still call WNY personally. Their prices are very attractive and you can do a number of different routes depending on how much you wanna spend. Their kits are quite comprehensive and they provide full, detailed instructions to walk you thru it. If you can run that hammer, you can put one of their phase converter kits together.

Phoenix Converter makes a good unit too, but I wasn't thrilled with the guy I talked to on the phone about some new caps for mine.

That's one heck of a nice hammer. A rotary converter would run it just fine. Here's a couple pix of mine to give you an idea. Mine is on wheels, but I don't have a lot of room and it's easy to roll to the work and connect it. You can get three phase motors from a lot of different places. You could call one of the phase converter companies to get the best advice on what kind to buy for the best performance with your machine. All the types of wiring styles are a little above my pay grade.

IMHO of course

I run this lathe off that static converter no problem. It's a pretty serious machine, although a far cry from a truly "big lathe"

A static converter will do the job, but not as efficiently as a rotary will. To buy a VFD big enough to run the motor powering that hammer, it won't be cheap. Not a quality one anyways and if I was gonna buy one, it would likely be ABB brand.

Good luck with it.

[Bo T]

15 hp, 240 v, 110 A ??? I am not sure you can get a single phase VFD for that?

[7A749]

I was under the impression you could use a three phase one at double the rating.

I was told this by a former employer who did a great deal of work on dairy farms and installed many VFDs on equipment. I have not verified this so that's about as much as I know about it.

The rotary is certainly the way to go in this case, at least as far as I'm concerned if it were mine. Being I already have one tho, it's a no brainier for me lol.

[Bo T]

I am just thinking of residential power as I don't know what input the OP has. If he has 3 ph to his shop, then it makes sense that his current draw would be about half of the single ph but I don't know.

[7A749]

This guy told me that a three phase VFD can be used on a single phase motor, supplied with single phase power but you have to double the size of it in order to do so. He was quite knowledgable about them and had installed a number of them on pumping and vacuum equipment used in the dairy business. I worked for him for awhile, he had a lot of experience with setting them up  and troubleshooting them. He had also set them up on several farms where only single phase power was available. I took him at his word, but again I would get some more info before I bought one to try it out. 

If the OP has 3 ph supply to his shop, he wouldn't need anything providing his service and motor voltage are compatible.

I imagine if he has a 10-15HP motor on that hammer a 15 HP rotary will run it. Startup is going to be the only tough part, but a well designed converter system will be able to do it no sweat, providing he has the input amperage to run it. I've run static and dynamic loads off mine on a 50 amp breaker. Of course, more amps would be better, but that's all I have. It will start the 250 amp Lincoln motor generator welders with absolutely no problem. Output was a little on the low side, but with only 50 amps supplying it, that's not a surprise. 

It will be a chunk of change to buy a new rotary that big, that's why I suggested building one, but there will still be some expense. On the other hand, when you buy a hammer this big, you already plan on getting pretty serious anyways.

IMHO of course

[Bo T]

It might be less expensive to have the power company run 3 ph power to his shop. If I understand things correctly, the advantage of a VFD would be the ability to change the speed of the hammer. While the rotary phase converter would simply convert single phase power to three phase power?

[Steve Sells]

there is a serious cost problem to get 3ph power installed,

Around here its a starting cost of  $1,500 per pole from where ever they have to go to tap the power. plus you sign a 5 year contract with a minimum monthly fee clause.

[7A749]

Mr Sells isnt kidding either.  It gets expensive REAL fast.

Then, when you get the first bill, you're likely to fall out of your shoes. Three phase power is billed very differently from residential power. You are charged by a peak demand rate, and that can fluctuate by how much you use, and at what time of the day. I'm not  super well versed in the billing formula, but the bottom line is they really stick it to you, and unless you use a LOT of power (and have income coming in to justify it) it's not a real practical way to go for the occasional user. Large industrial users often have arrangements with the power supplier and pay a much lower price per KWH than a small user will. But again, they're buying a LOT of it at once. 

I know a couple guys who run large phase converters to power their shops, which aren't huge but are running several mills, lathes and welders at once with maybe under 8 employees. It is cheaper for them to run the large rotary than to pony up the money to run a three phase service in, then pay the monthly bill. Again, for BIG operations using lots of power, it has clear advantages but for something like this, or even a larger small business it's going to be an added expense for sure.

As far as the VFD, they do have advantages, mainly that they can do more than a static converter, and as mentioned the speed can be varied by changing the frequency of power fed to the motor. They do however have their foibles and if you have a problem with one, opening your wallet really wide is the best way to fix them. They can also be very hard on motors and in some cases, wear them out faster than running at one frequency all the time. Rotary converters run quite efficiently, and if one were to buy a pre made control and install it to a properly rated motor, they really can be a cost effective way to operate big machinery on a small level operation. The other good thing about them is that rotary converters can power resistive loads such as welders with a high degree of success. I've powered several 400 amp machines off mine, and although not a full output, they operate at very acceptable levels. The only thing limiting me in my case is the size breaker I have it on. 50 amps is all I have to work with. Of course, in my situation I'm not running several pieces of equipment at once and I'm the only one running it.

Hopefully we will hear more about the hammer and how the OP sets it up. It looks like a pretty sweet machine from where I'm sitting

IMHO of course

[Kozzy]

A quick search shows a VFD rated for 220V single phase in, good for 15 hp out, can be had for $ 1400...and probably cheaper with a thorough search.  If you count your time, a rotary is probably getting toward that end of costs--a little cheaper if you can find good used parts.  Remember that the motor in a rotary has to be over-sized quite a bit to work properly so you are also talking something in the range of 25 HP and the corresponding hardware to handle that load, not just he 15 of the machine. All that adds cost.

Having used a rotary in my old shop and switching to VFD on several machines I would highly recommend going the VFD route.  Shop space, for one--floor space is always at a premium and a large converter hogs that.  I also HATED the constant whine of the rotary as they're not worth shutting off even if you shut down the machine they feed for a couple of minutes.  The features of a VFD are also nice, even if you don't expect to use many of them.

Now that I have 3 phase in the shop, I still stick to VFD on many things for the speed control, soft start, digital feedback as to RPM, etc.  Just plain nice to have.

Just an opinion, YMMV.

[7A749]

I've never run any real big motors off mine. I honestly didn't think it would have to be that much bigger, but it stands to reason it would for the startup at minimum. Those VFDs kinda freak me out . I just see one blowing up on me right after the warranty runs out lol. The guy I worked for swore by ABBs offerings. They're not cheap by any stretch of the imagination tho, but I suppose a used one in good working order wouldn't be too awful bad price wise. 

I am going to put one on a belt grinder I just picked up tho. It will be my first direct experience with one. We dealt with them on the farm, but that's about the extent of my experience with them. I definitely want something quality and I'll pay for it rather than end up with something junk. I like my rotary, but I don't have much in it and it fits my needs ok. I have to have it for running welding machines after a repair to test them. Before, I was hauling them to a buddy's shop and that was a royal pain.

What are you using for VFDs brand Wise?

[timgunn1962]

I know it's contrary to most of the advice you'll get, but I'd go with one of the cheap Chinese HuanYang drives in the OPs position.

There are a couple of reasons for this.

I have yet to encounter a large (4 kW and up) VFD from any of the major manufacturers that will actually run off a single input phase. I have seen all the stuff on the web about needing to derate if you do run on single phase, but all of the drives I've actually played with give a fault message and refuse to run if there are not 3 phases present.

I'm in the UK so things may be a bit different in the States, but please check carefully before buying.

The HuanYang drives up to 10 HP, 7.5 kW will run on a single input phase without derate and without showing a fault. Most of the RPC specs I've seen seem to give a maximum single motor start of roughly 2/3rds the RPC motor size, so I'm guessing the 15 HP rotary mentioned in the OP is to start a 10 HP motor.

I get the impression that the manufacturer has taken a pragmatic approach to things and massively oversized the input stage compared to western drives, hence the zero derate on single phase. I certainly find I can run a 3 HP, 2.2 kW  HuanYang drive on a small gasoline-powered generator, where a 2.2 kW ABB drive simply refuses to run.

KBAC drives seem popular in the US and are widely recommended on the knifemaking & smithing forums, mainly because they are sealed drives. I don't think there is a bigger single-phase-input KBAC drive than the 29 (3 HP, 2.2 kW), so the choices seem to be another manufacturer's sealed drive (if you can find one that runs on single-phase), or box up an unsealed drive. The box cost is likely to be about the same regardless of manufacturer, making the cheapest drive the cheapest option. 

I tend to tinker around with stuff a lot and the VFDs in my shop are mounted in boxes with 3-phase sockets and remote control pendants so that I can plug in whatever machine I want to power at the time. The protection settings in the drive therefore tend to be left at factory default (invariably set for the biggest motor that the drive will run). I always assume that, at some point, I'll try running some machine I've found, built or am trying to fix and there will be a fault that will kill the drive. It's much easier to accept this if the drive you are going to kill is a $120 unit than if it's a $500 unit.

A HuanYang drive to fit plus a spare to keep on a shelf against the day the first one dies still works out cheaper than a big-name drive over here.  

Where I would go for a big-name drive is if I needed a particularly low minimum speed, in which case I'd buy an SV drive. In my experience, Sensorless Vector drives will drive smoothly down to under 3 Hz, where V/Hz drives seem to start feeling "coggy" somewhere between 10 Hz and 7 Hz. 

On 5/24/2016 at 4:21 PM, 7A749 said:

I've never run any real big motors off mine. I honestly didn't think it would have to be that much bigger, but it stands to reason it would for the startup at minimum. Those VFDs kinda freak me out . I just see one blowing up on me right after the warranty runs out lol. The guy I worked for swore by ABBs offerings. They're not cheap by any stretch of the imagination tho, but I suppose a used one in good working order wouldn't be too awful bad price wise. 

I am going to put one on a belt grinder I just picked up tho. It will be my first direct experience with one. We dealt with them on the farm, but that's about the extent of my experience with them. I definitely want something quality and I'll pay for it rather than end up with something junk. I like my rotary, but I don't have much in it and it fits my needs ok. I have to have it for running welding machines after a repair to test them. Before, I was hauling them to a buddy's shop and that was a royal pain.

What are you using for VFDs brand Wise?

I would not buy a used VFD. Period.

For the grinder, the choices are KBAC for minimal hassle at not-ridiculous cost, cheap Chinese and box it yourself (more hassle and usually significantly cheaper than a KBAC) or "known brand" and box it yourself (more hassle and usually more expensive than a KBAC).

[7A749]

Thank you so much for the info. I don't know jack about them besides what I've stated above and was hoping for something like this. I only have limited experience with the three phase ones that ran the pumps on the dairy farm. I have two belt grinders I recently acquired and would like to have vari speed on at least one. I'll look into what you suggested. Running anything other than a welder is a pain with the rotary. It works good for what it does (run three phase welding equipment for testing after repairs).

We are planning a move to another state in the future and I plan on a 25 HP rotary for running three phase stuff with a transformer for 460, but it will be mainly for running and testing welders I repair. I may end up running it off a VFD but I kinda like the "buy it and mostly forget it" approach you get with a rotary. They're fairly simple and not a lot to go wrong down the road. The VFD pukes and you're buying a new one.

Thanks again for the info and warning to stay away from the used stuff. Sincerely appreciate it!

[Richard Furrer]

I have a 30hp rotary by these guys

https://www.americanrotary.com

Bought it new and I have been running it for about ten-11 years with no issue other than having to grease it and my electrician did find it was a bit out of the 10% rating they claimed, but this was settled by adding another capacitor.

Their units come up on craigslist from time to time.

I have had no issues with my old ten Hp nazel motor in cold weather and have started a 25hp easy start load with the 30hp converter so I call it good.

The thing about a rotary is that you need a 3phase panel for it to feed to BUT then you have the ability to run other there phase tools......not that simple with a VFD.

I have a 10amp VFD which takes 220 single phase and runs my 3 phase belt sander to get variable speed on that three phase motor.

YOU CAN NOT RUN A VFD ON A ROTARY there are issues with feedback and harmonics and not having an actual third leg. For VFD I suggest single phase to three phase and stay with smaller units......5hp and smaller.

I have some larger 480 volt machines and have been installing a 100kw generator to feed those. Bringing in line power three phase to me would be about $56k as I would have to pay for the poles and wire for 1/3 of a mile. A generator was an easy choice.........especially since I do have a large natural gas line to the shop.

Ric

[7A749]

Didn't know the part about the rotary not running off a VFD either. I knew it was usually one control to a motor. They won't run welders either.

This thread has proven most informative. American Rotary is top gear all the way. Good stuff.

I totally agree with you on the rotary converter. Mine has served me well and cost almost nothing.

Where did you get the VFD for your sander? Just wondered 

[7A749]

Oh, Richard. Did you ever consider a transformer off the rotary, or didn't you have enough KVA to run it? I was planning on one (or running a suitable unit in reverse) just to put high voltage welders under power. It would be much easier than having to change jumpers versus throwing a switch and getting enough output to run the machine to an acceptable level.

I load test stuff I work on around 200 amps on average. That's all my service to the garage will support. I have run some 400 amp machines off my rotary on a 50 amp breaker and did close to 300 amps, but that was about as far as I wanted to push it. It will run my Lincoln motor generator but there is a noticeable reduction in output. I have to check the rpm on it and see where I'm at.

What are you running off your converter?

[Richard Furrer]

OK as to VFD off rotary:

I was told that by American Rotary as I wanted to do that here.......and was warned off. Now they seem to claim it on the website as a use for the rotary converters they sell.......so What do I know?!? I thought it had to do with faking the third leg and the VFD using all legs to get the job done.

I run my 3B Nazel's ten hp, any smaller motors needed, 20 hp rolling mill, will soon add 15 hp twister, 15hp hydraulic etc.

VFD on grinder:

http://www.temcoindustrialpower.com/products/Variable_Frequency_Drives/C80009.html

I have it in an enclosure with a filer and cooling fan as its a NEMA1 thing...They make a NEMA4 or better which may be worth the money.

Others have used other brands and there are less detailed ones by the same company...I do not use the features on the thing....manual is 120 pages long.

[7A749]

Thanks for the info Richard. You have some nice equipment by the sounds of it.

Ive always viewed American Rotary as quite reputable. Maybe they done something different with the VFDs they're running on rotary converters? Who knows. The one thing I really like about the standard setups is that once you put it in service, there's few things likely to go wrong with it. I repair a lot of older Miller inverter welders and they're great until the stop working. Usually when they puke, it's serious and expensive. Overall they have a good service record tho. I just like "install it and forget about it" reasoning for something that will be under electrical load constantly while it's running. I would have went that route when I first installed the electrical in my garage shop, but the rotary came many years after the fact.

It would be a waste of money in my circumstances to install a service to run off the rotary now. I have a test lead for it with large jaw clips that can attach to either terminal lugs or to stripped ends of cord.

I like how the Burr King setup is with a speed dial right on the front of the machine. It's running off a VFD I'm sure, so that's kinda the plan there. I don't need vari speed on all my grinders, just one would be nice and since it already has a powerful three phase motor there's absolutely no point in removing it to put a single phase motor on it for about the same price as a VFD. I have a number of Hoffman style boxes, putting it in one with a muffin fan would be a piece of cake. Once I get this welder/feeder combo I'm working on done and out the door, I'm gonna tear down the Ruman belt grinder I have and start working on it.

Thanks again for the info Richard.

Steve

[Bob Brandl]

Thank you all So much for your info and insight! 

[7A749]

Please post up pics of the machine. It looks fabulous!!!

[AlanB]

I realize that this is obvious and you are probably set on operating 3 phase but it occurs to me that if this was the only 3 ph equipment in my shop and my power was limited to single phase, I would just buy a 15hp single phase motor with suitable pulleys to produce desired speed and forget fooling with phase converters or the cost of adding 3 phase power to the shop. No?

[7A749]

Finding a single phase motor that size used is going to be difficult and expensive. Get up into the ten Hp plus range and prices get stupid ridiculous and options are limited. Buy new you're easily in the $1200 and up range for 10 HP. Didn't even see a 15 HP listed on baldors site but didn't look real hard just now. You'll need some serious power to run it too. You can get away with much less running a converter since either the VFD or capacitor bank absorbs the starting load, or in the case of VFDs they can soft start 

Thats why most ppl go the VFD or rotary converter route to power three phase equipment in smaller shops. 

Been my experience anyways.

[timgunn1962]

Here in the UK, single-phase motors over about 3HP (2.2 kW) are unusual. Anything in the 10 HP range and up is likely to be a special and horribly expensive.

I've seen a few 2-pole 4HP- (3 kW-) single phase motors on reciprocating compressors to try to maximise their output on single-phase power, but I don't recall seeing anything any bigger on single-phase.

Most (all?) of the 3-phase motors I've seen above about 7.5 HP ( 5.5 kW) are wound for 400V Delta/690V Star to allow Star-Delta (Wye-Delta) starting on 400V 3-phase supplies. This is intended to keep the starting current down. Direct-On-Line (Across-The-Line) starting often pulls between 6 and 7 times the rated current, where Star-Delta starting "only" pulls about 2 1/2 times rated current. 

Almost all of the 3-phase motors I've seen of less than about 4 HP (3 kW) have been wound 230V Delta/400V Star and these can be run from a 230V-in VFD or a transformerless Phase Converter.

Between 3 kW and 7.5 kW, things are less clear-cut: some motors are wound 230V/400V and others are wound 400V/690V, making it a case of check before buying. 

The 400V/690V motors need a step-up transformer in the system to get the Voltage up to 400V before either the Phase Converter or the VFD does its thing. VFDs are available, albeit at a cost, with the transformer built in. These are often described as "Digital Phase Converters". Both Static and Rotary Phase Converters here have the transformer in. 

Of course you can buy a transformer and a 400V-in VFD and effectively make your own DPC, but you'll need a VFD that will actually run on a single-phase 400V supply.

The thresholds on motor sizes and Voltage may be quite different in the States, as the power distribution system is completely different. I think small industrial 3-phase is usually around 230V and the big stuff runs 460V, but I'm not 100% sure.

 

 

[AlanB]

I realize that this is obvious and you are probably set on operating 3 phase but it occurs to me that if this was the only 3 ph equipment in my shop and my power was limited to single phase, I would just buy a 15hp single phase motor with suitable pulleys to produce desired speed and forget fooling with phase converters or the cost of adding 3 phase power to the shop. No?

Here's a 10hp single phase compressor duty 1750rpm from Northern Tools for $850

http://www.northerntool.com/shop/tools/product_200381915_200381915

(you might not get much more than 10hp from a 3ph 15hp running on a converter)

[BIGGUNDOCTOR]

ARCO Roto-Phase is the company that made mine. It will start up to a 15hp, and run a combined 60. I never hooked it up, as I just used a second 3 ph motor and wired through it to run my Monarch lathe, surface grinder,and milling machine..  That convertor used was $1,300, new it was $4,200 and designed for CNC's. I have a 650A Miller MP65-E MIG that is 3ph, and that convertor would give me 50% output. 

I can get 480 3ph run across the street to may property for $12,000. $7,000 of that is the 75kva transformer.