LumberJocks

3ph 5hp Powermatic 66

  • Advertise with us

« back to Power Tools, Hardware and Accessories forum

Forum topic by RickEmery posted 06-14-2017 03:42 AM 490 views 0 times favorited 12 replies Add to Favorites Watch
View RickEmery's profile

RickEmery

6 posts in 230 days


06-14-2017 03:42 AM

I currently have a Craftsman 22124 tablesaw, which has been a great. The other day I was offered a PM 66 for an unbelievable good deal. However, the saw is three phase. I have read as much as I could on VFD and rotary converters. I have pretty much settled on a VFD for the phase conversion. I am pretty good with electrical wiring; having wired my original shop and sub-panel. I feel somewhat apprehensive using a VFD on this machine. The saw is such a bargain, I am trying to think of reasons not to go this route. Any thoughts would be appreciated.


12 replies so far

View a1Jim's profile

a1Jim

116561 posts in 3411 days


#1 posted 06-14-2017 03:56 AM

Have you compared the cost of a single motor instead of going the phase converter route. When shopping for a table saw many times the 3 phase saws have much lower prices because there’s a much smaller buyer base for them.
I had a PM 66 for years and loved it ,I recently switched to a Sawstop 5hp commercial just for the safety factor and its the only saw that can compare to a PM66.

-- http://artisticwoodstudio.com Custom furniture

View KelleyCrafts's profile

KelleyCrafts

2680 posts in 573 days


#2 posted 06-14-2017 05:01 AM

In my search for my lifetime tablesaw I was looking for a PM66 or a good Unitas but didn’t find one before my PM72 came about. I am running the PM72 with a phase-o-matic and extremely happy with the saw. I say go for it.

-- http://kelleycrafts.com/ - pen blanks - knife scales - turning tools

View MrUnix's profile

MrUnix

5983 posts in 2033 days


#3 posted 06-14-2017 07:51 PM

I feel somewhat apprehensive using a VFD on this machine.

Why? It’s as simple as three wires in, four wires out. Hardest part is figuring out where to mount it.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View Carloz's profile

Carloz

962 posts in 426 days


#4 posted 06-14-2017 08:04 PM

Just buy a capacitor for $10 or so and be done with it. Your starting torque will not be as great as with true 3 phase motor but a table saw does not need much starting torque (unless you start cutting wood before you start the saw :-) ) . Expect to loose 30% or so power.

View MrUnix's profile

MrUnix

5983 posts in 2033 days


#5 posted 06-14-2017 08:06 PM

Expect to loose 30% or so power.

And run hot from being unbalanced. Push it hard in that configuration and you will toast the windings pretty quick.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View Mainiac Matt 's profile

Mainiac Matt

7456 posts in 2163 days


#6 posted 06-14-2017 08:19 PM

We run a 5 HP 3 ph PM66 at work and it’s a great saw.

and Jim is right, 3 ph equipment sells for a lot less.

I’ve looked into it several times and your options are pretty much as follows:

1. replace the motor with a single phase motor. But a good single phase 3 HP motor will run you upwards of $300.
2. Buy (or make) a static invertor. This uses a capacitor to create an artificial third leg to get the motor rolling. The you have two poles driving the motor and the third pole acting as a generator. You take a hit on the overall HP rating, but a lot of people do this. Phase-o-matic sells them for ~$150 and they have to be sized for your machines HP rating. the starting capacitor is often on a timer circuit and then a smaller run capacitor is used to balance the phase angle between the legs. BUT… if the machine has contactors that run auxiliary functions (limit switches, coolant sump pumps, etc…) you will often find that the invertor will not properly trigger those contacts and drive those functions.
3. Buy (or make) a rotary invertor. This uses a 3 phase motor and static invertor to get it rolling. This motor then generates the third leg which can be wired to run multiple 3 phase machines. The prices on these have come down, and Grizzly sells a nice ones for ~$500-900 depending on the HP rating. This will allow you to run multiple 3 PH machines, just as if you had it coming in from the utility company.
4. Use an DC invertor. This option is definitely the way to go for variable speed applications (think drill press or lathe). Getting the right invertor specified for you motor is crucial. And if you buy the wrong one, they won’t take it back. For a 220 v 5 HP machine, you’ll wind up paying ~$400 or more, but the prices on these have also come down in recent years.
5. Pay to get your shop wired for 3 PH and get a 3 ph drop from the utility company. The price of this depends on how far you are from then nearest 3 ph pole. But it will easily run thousands of dollars.

My personal pic would be to build a rotary phase convertor, as I salvaged a 7 HP industrial duty 3 ph motor several years ago, and the plans for convertors are readily available on line.

HOWEVER…. if you screw it up and burn your house down, your insurance company may well deny the claim.

-- Pine is fine, but Oak's no joke!

View Lee's profile

Lee

95 posts in 712 days


#7 posted 06-14-2017 09:17 PM

Here’s a Teco 5hp single phase 230v input vfd for $358 with 17.5 amps constant torque output. check the name plate on your motor for the fla. In my opinion this is the way to go, unless you can find a single phase motor for about the same price. You get the full power of a 5hp motor, witch is more than enough for a home workshop. My PM66 has a 3hp motor and I’ve never bogged it down.
http://dealerselectric.com/MA7200-2005-N1.asp

-- Colombia Custom woodworking

View MrUnix's profile

MrUnix

5983 posts in 2033 days


#8 posted 06-14-2017 09:53 PM

Here’s a Teco 5hp single phase 230v input vfd for $358 with 17.5 amps constant torque output.
[...] http://dealerselectric.com/MA7200-2005-N1.asp
- Lee

Unfortunately, I do not believe that VFD will accept single phase input… only their 1-3hp models will. 5hp and up requires three phase input, which is specified in the manual and sales brochure.

Get the FLA of the motor. There are plenty of people running 5hp machines (PM72, Delta 12/14, etc…) on single phase input VFD’s rated at “3hp”. You will find plenty of examples over at the OWWM and practicalmachinest web sites. The VFD can supply up to 150% of rated current for short periods of time (like ~1 minute), and the motor will rarely, if ever, see FLA. Otherwise, there are single phase input VFD’s that can do more current, but they can get expensive.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View RickEmery's profile

RickEmery

6 posts in 230 days


#9 posted 06-15-2017 12:15 AM

Thank you all for your assistance. The VFD 3hp is what I was reading everyone used. A single phased motor would make the deal on the saw not so good. I saw on VFD that was rated a 5hp but the $$$ was crazy.

View Carloz's profile

Carloz

962 posts in 426 days


#10 posted 06-15-2017 01:06 AM

Instead of guesswork I would suggest to do a little research. Running 3 windings (i deliberately did not say phases) with capacitors on a single phase is a reliable and often used mode. With the right capacitor the 2 auxiliary windings shift phase 90 degrees and becomes a single phase motor not worse and not better than a motor with 2 windings.
Internally some single phase motors especially older ones are actually 3 phase motors.
I would challenge you to overload or even heat above normal such 5hp motor on a table saw with 10” blade.


Expect to loose 30% or so power.

And run hot from being unbalanced. Push it hard in that configuration and you will toast the windings pretty quick.

Cheers,
Brad

- MrUnix


View Lee's profile

Lee

95 posts in 712 days


#11 posted 06-15-2017 02:57 PM



Here’s a Teco 5hp single phase 230v input vfd for $358 with 17.5 amps constant torque output.
[...] http://dealerselectric.com/MA7200-2005-N1.asp
- Lee

Unfortunately, I do not believe that VFD will accept single phase input… only their 1-3hp models will. 5hp and up requires three phase input, which is specified in the manual and sales brochure.

Get the FLA of the motor. There are plenty of people running 5hp machines (PM72, Delta 12/14, etc…) on single phase input VFD s rated at “3hp”. You will find plenty of examples over at the OWWM and practicalmachinest web sites. The VFD can supply up to 150% of rated current for short periods of time (like ~1 minute), and the motor will rarely, if ever, see FLA. Otherwise, there are single phase input VFD s that can do more current, but they can get expensive.

Cheers,
Brad

- MrUnix


Look on page 15 of the TECO MA7200 manual, it says, and I quote, (For single phase power supply, please use R/L1, S/L2 as input terminal)

-- Colombia Custom woodworking

View MrUnix's profile

MrUnix

5983 posts in 2033 days


#12 posted 06-15-2017 07:48 PM

Look on page 15 of the TECO MA7200 manual, it says, and I quote, (For single phase power supply, please use R/L1, S/L2 as input terminal)
- Lee

Yup, that is the generic instructions since they use the same terminal blocks across their line of inverters. They do the same on most of their inverters… for example, the 3hp FM50 has markings for single phase 120v input, even though it can’t use 120v as input :)

Here are the wiring specs (from the same manual) for their line of inverters… notice that single phase is directly supported only up to 3hp:

Actually, the first page of the manual states that the 1-3hp models can do single/three phase input, while anything larger wants three phase input. That is not to say you can’t use single phase, but you would need to de-rate the inverter (typically ~50-70%)... so for a “5hp” motor, you would need a “10hp” or larger inverter if you want to run it on single phase. YMMV.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com