Phase converter or new motor.

[chet Weatherl]

I recently acquired a Powermatic 66 with a 5 HP three phase motor. The problem is, I haven't any three phase in my shop. The question is, should I buy a phase converter, or a new single phase 3 HP motor. The two aren't that far apart in price and I really want to get this up and running. I'd really appreciate your input. Thanks, Chet

[Mike Wilkins]

You have 2 options here:
1. Contact the Powermatic company to see if there is a compatable single phase motor that will mount without major modifications.
2. Purchase a phase converter, which will allow you to consider other machines with 3 phase motors. There is a whole world of used machinery on the market
which is only available in 3 phase.
Just my 2 cents.

[Greg Bender]

Chet,
hit ebay and see which one solves itself first.I've found some great deals on good motors on the bay.You never know.
Greg

[fRED mCnEILL]

I bought a table saw with a 5 hp 3 phase motor. I was able to get a rotary phase converter for cheap(150 I think) and it works very well. But it does involve an extra step each time you use the saw as you have to start the phase converter first and then the saw. Unless you leave the phase converter running. And, of course, you have one more piece of equipment to have something go wrong on. But it does function very well. So if you had a choice of a new motor or phase converter at the same price go for the new motor. Ya, there is lots of 3 phase used stuff available but is that something you are interested in.

[Kent A Bathurst]

Vfd?


...................

[Jeff Monson]

There are alot of people on this forum that swear by VFD's I know you will loose some HP but they are inexpensive.
I use a rotary phase converter, yes it is an extra step to take on startup, I have mine on a remote control. I'd go
with a phase converter of some type, 3 phase machines seem to sell very reasonable and there is a large selection out there.
If you do a seach you will find alot of great threads on phase converters here on SMC. Also wiring them in is fairly simple.

[Salvatore Buscemi]

Vfd?


...................

Have you looked at the price of a 5hp VFD? They get pretty expensive at that high of hp.

[Rick Christopherson]

There are alot of people on this forum that swear by VFD's I know you will loose some HP but they are inexpensive.I've seen a couple people say this here. Who on this forum is telling people this? VFD's do not result in any reduction of power. As a matter of fact, they are the only type of conversion that does provide full power.

[Chip Lindley]

VFDs are great for smaller 3ph motors, but get rather pricy, into the realm of RPCs when you need to run a 5hp machine. There are RPC "panels" available at quite a savings, that allow you to find and use your own 3ph motor as the generator.

I am a strong RPC proponent, because when I found mine, after finding a PM Model 26 5hp 3ph shaper, other 3ph machinery started coming out of the woodwork!! A decent RPC rated to start and run a 5hp motor will serve you well. It will run any future machine up to 5hp. And it will run multiple machines at the same time, should you have the need. Say, a 3ph dust collector up to 5hp, while your PM66 is running. An RPC can be connected to a remote control wireless starter same as a DC can. It is a painless and convenient way to control your RPC with a little keychain pushbutton unit.

[Jeff Monson]

I've seen a couple people say this here. Who on this forum is telling people this? VFD's do not result in any reduction of power. As a matter of fact, they are the only type of conversion that does provide full power.

Sorry Rick, I meant static phase converter. Some days I wonder where my brain is.

[Kent A Bathurst]

Have you looked at the price of a 5hp VFD? They get pretty expensive at that high of hp.

I realize that. It is a 3d option that had not beeen mentioned up to that point. Plus - if he is rummaging around auction sites, never know when you'll stumble across a deal. No need pre-censoring the alternatives, I figured.

[Salvatore Buscemi]

I realize that. It is a 3d option that had not beeen mentioned up to that point. Plus - if he is rummaging around auction sites, never know when you'll stumble across a deal. No need pre-censoring the alternatives, I figured.

Good point.

I just remember nearly soiling myself when I bought a saw with a 7.5 hp 3phase motor, and *then* checked how much it would cost to get running.

[Greg Portland]

You have a couple of options:

Static converter: cheapest option but the tool motor will not provide full power
Rotary converter: Uses a motor to generate 3ph, results in full power to the tool. This is not as efficient as a VFD.
VFD: This is a solid state solution that is $$$ but will provide the highest efficiency. You will want to make sure that your VFD is going to work with your tool's motor. Also, some VFDs are only capable of driving 1 motor at a time. In short, make sure you know what you're getting.

[Jeff Monson]

Chet, There is a Kay industries MA-2 rotary phase converter for sale on the Felders owners group website, it is located in Rohnert Park, California. The author says make an offer, may be of intrest to you. Kay makes a really durable RPC

[Mike Cruz]

Chet, I've had this dilemma on two pieces of machinery now, a BS and a lathe. For me, a VFD (3 phase converter with speed control) was the answer. But that was because the VFD gave me the option of speed control. I can't see why you would want or need that on a TS. Persoanally I would start with how old the motor is. If you could get a new 3 hp 1 ph motor for what the phase converter costs, I would lean towards the new motor. I've found 3 hp to be plenty powerful on a TS. If you go with the phase converter, and the motor ever fails (unlikely, but possible) then you still have to buy another motor. The only reason I would see to go with the phase converter in your case is if you think you might want to do 3 phase on any other machines in the future. Honestly, though, dedicated VFDs aren't that expensive for 3 hp and under motors. My TECO FM50 3 hp was $184 and the TECO FM50 2 hp was $145. Both offer variable speed control, reversing, programed start up and slow down speeds, and a whole slew of other stuff. Just my two cents.

[Jonathan Spool]

I went with a used 5hp VFD for my planer ($220). Not only does it works well, but it runs both the head and drive motors, and the slow startup eliminates any power draw spikes. Only thing I don't like about it is the high pitch whistle that eminates from it! Much better than any static converter I've ever used. I didn't go with a RPC as I didn't want the extra step in starting it up. Once you go with an automated RPC your back in the price range or more of a new VFD.

[Rick Fisher]

I run a digital converter.. Not sure why Rick says a VFD is the only conversion that offers " Full Power " .. but I know he knows a bunch about this stuff..

The Digital provides very clean power.. Mine supplys 240, 240, 242 Voltage. Its quiet, you turn it on when you enter the shop, turn it off when you leave.. It draws 200 Watts when idling and makes a mild whistling sound..

IMO.. When looking at a Phase converter, you should decide if you plan on getting more machinery which is 3 Phase ?

A VFD for 5hp is a bit expensive. For a Domestic Table Saw, it would be a simple solution.. I have a 220V PH3 x 4hp Jointer which cannot be run from a VFD at all.. Its what led me to look for something different.

If you are feeling spendy, and think you will get more PH3 Machinery, a larger capacity converter will be a real bonus..

My converter can supply about 60 amps of 220V PH3.. it runs to a PH3 Panel, which is hard wired to 2 machines .. If I add another PH3 machine, I simply snap in a breaker and run teck cable to the new machine.. Simple..

If you decide on a new motor, it would be a pretty easy swap out . A 5hp PH3 will draw close to the same amperage as a 3HP PH1.. so technically, the electronics on the saw should work as is..

[Kent A Bathurst]

I have a "new-to-me" old DP - PM1150VS. Has a replacement 1ph motor, but the PO threw in the OEM 3ph as part of the deal. I have considered at some point swapping the motors back, and installing a VFD for speed control. While that seems on the surface like a bit of overkill [VFD on a VS DP??? Whaddyar ya, nuts?] there are some marginal benefits. Not very high on my list, I admit.

However, if I was ever in the market for another big arn DP [not likely], I'd consider a 3ph belts + pulleys style, and add a VFD. Also, if I was in the market for a shaper [less likely - I don't even have a router table today] I would most definitely look for a 3ph, and put on a VFD. The underlying point is the price/performance of used 3ph equipment, and the ability to go to 1ph and add speed control.

Speed control has nothing to do with the PO's TS, of course - unless I am really missing something.

[Larry Edgerton]

VFD's in conjunction with old motors can be a problem if run at either end of the rpm range for too long. The insulation in old motors is not up to the job and can burn out if run at the extremes. Something to keep in mind.

[Kent A Bathurst]

Good tip, Larry - thnx

[Jim Neeley]

This is technically correct but would benefit from an explanation... heating can be a problem for any fan-cooled motor that is run at very slow speeds, under load, for an extended time unless the fan was sized large because under full load just because the speed is 25% of max doesn't mean the power is low. If it's delivering 5hp, its delivering 5hp. The excessive heating can degrade insulation.

Top speed can be a problem because the VFDs typically let you "overdrive" the motor.. i.e. faster than it would run without the VFD. This also taxes the insulation; not a problem for good insulation but if the insulation was old and cracked....

[Salvatore Buscemi]

VFD's in conjunction with old motors can be a problem if run at either end of the rpm range for too long. The insulation in old motors is not up to the job and can burn out if run at the extremes. Something to keep in mind.

What do you mean by either end (not trying to be a smart alec)? Any why would you be doing this with a table saw?

[Rick Fisher]

Its not something you would do with a table saw, but you may do it with a drill press or another type of tool.
A motor will produce a lot of heat when under load.. if the fan is spinning slow because of the RPM being reduced.. the motor can overheat..

3 Phase motors are much smoother IMO. They are also simpler, less troublesome motors. They usually create less vibration as well.

[Larry Edgerton]

What do you mean by either end (not trying to be a smart alec)? Any why would you be doing this with a table saw?

You would not use the speed control on a tablesaw for any reason that I could think of, but the discussion had brought up that feature of VFD's. By either end I mean running it as fast or as slow as the VFD will allow it creates more heat, and insulation materials in electric motors have evolved. Most modern motors have better insulation than old school motors, although old school motors have the advantage of more mass in many cases. Even if you had a newer inverter duty motor you would not want to use the VFD for your speed control if you had other options, its still creating more heat.

In my case I did some digging because I had a Walker-Turner drill press that I wanted to run without running my 50hp converter. The Press has its original motor. In conversations with the techs at Factorymation these points were brought up, and we decided for my application it would be fine because I don't sit at the drill press all day and I would not need to use the VFD as a speed control. Same with my lathe, a 3hp Brodhead Garrett from the 50's with mechanical speed control. I may put a VFD on it so I can use it in my basement just for fun and have no 3 ph there.

In other words if your machine has a mechanical speed control, you want to use it first and keep your motor at its optimum operating rpm, and then use your VFD if needed, if you have old iron like I do. The motor on my drill press is so huge I am not really worried about it, but the lathe with its physically smaller motor, running in continious duty, I would worry about.

I see references quite often to people with VFD's ignoring their mechanical speed controls because they have a VFD, and from my research that is not a good thing, especially on something like a lathe that can be under load for a long time. That is why I posted that bit....

[Larry Edgerton]

Rick

I take it that you are still happy with your Phase Perfect?

I would love to not have to listen to that growling 50hp RPC so have been looking at those. Hoping the price drops a bit........

[Paul Grothouse]

Call this company they specialize in converting equipment for Amish use. They take off the electic motors and controls and replace with hydraulic motors. I have purchased a number of brand new unisaw and powermatic motors from them over the years at a low cost. Make sure you get the single phase contactors as well. This will cost a great deal less than a convertor and be easier to implement.

http://www.blueballmachine.com/

If your dead set on a convertor. Contact this company, it is an automatic convertor, that starts the convertor based on demand. I have two very large ones and they are best you can buy. Plus it can auto start your dust collector. I also think it is the only UL convertor on the market. Btw, rotary is the only way to go.

http://www.tcwtech.com/workshop-products.htm

[Rick Fisher]

Larry..

Yeah.. I actually like it a bunch. The company has a patent. when the patent expires, the price will plummet.. Its so simple and silent..

I only have 2 x 3PH motors, a 12hp and a 4hp .. The converter is rated at 20hp and connected to a 100amp breaker.. I can fire up both machines at once, no fuss..

I went 20hp instead of 10hp because so many industrial machines use 10hp and 12hp motors.. thinking of shapers and sliders.. I dont have either.. but I am ready .. lol

[Rick Christopherson]

I run a digital converter.. Not sure why Rick says a VFD is the only conversion that offers " Full Power " .. but I know he knows a bunch about this stuff..
Sorry, that wasn't intended as a slight against digital converters. Digital converters fall into the same category as VFDs but with just a fixed frequency.

[Don Buck]

I faced a similar issue last year when I purchased a 3 ph 20" Delta bandsaw. I was leaning towards "just replacing the motor" but soon found out that on my saw it would also mean replacing the 3 ph starter switch with a 1 ph starter which was going to be very costly if I was going to use Delta parts. I opted for rotary phase converter combined with a used distribution panel and used fused disconnect. I found the used components through a search on eBay where I found a "store" that sold used electrical boxes and I contacted him for the parts I needed and didn't spend much over $100 for the distributon panel and disconnect total. I have been very satisfied with my rotary converter, I went with American Rotary, very pleased with purchase and customer support, they will steer you to the right sized converter. Still more costly than a VFD but I have since added a 3 ph radial arm saw so I have no regrets.