3ph 3 hp PM66- new motor or vfd?

[Chris Hachet]

Geoff,
A big thank you for the information. I'll check the existing starter on the TS tonight to see if it would work for a single phase replacement motor. (Baldor $385)

I also found the correct VFD (TECO FM50-203C $200). The VFD would save me a bit of money but I'm going to watch the installation video before making any decisions.

Yes, I'm excited to get the PM up and running . It has the old style fence but I believe it to be in good working order since the shop teacher had been using it. He ordered the saw for the middle school in 74' and took it out of commission when they closed shop in the mid 80s but kept the saw there for school needs. They closed the school down and now he has a garage filled with PM 3 phase equipment! He invited me to keep loading my trailer with low ball prices but I somehow managed to show some restraint.

A good sized enclosure on the back of the saw will help with heat issues as you will develop a bit of heat if you ahve extended sawing sessions. I also vacuum out my VFD enclosures with a HEPA (festool) vac every so often to keep the inevitable dust away from them.

[Don Jarvie]

I've done the same motor swap on my 66 and it was the same year, 1974. If the new motor has an internal overload protection then having the overload protection via the starter isnt necessary. If the motor doesnt you will need the heaters in the starter. A magnetic starter is nice but you could use a 30 amp toggle switch (light switch type) since the magnetic starter will be just used for on/off.
Im my case the motor didnt have any interal overload so I had to replace the starter and adaquate heaters. If you want to use a magnetic starter you will need a Size 1 to handle a 3hp single phase motor. Most likely the starter you have is a Size 0 which is fine for a 3 phase motor but not a single phase. I liked the way the Furnas starter looked so I found a Size 1 on Ebay that fit my enclosure.
The motor size is a 145TC. You can use a 56C but you will need to replace the pulley since the 56 have a 5/8 shart compare to the 145 which is a 7/8 shaft. You will need a C frame since the motor bolts to the frame. I got a 56C so I swapped out both pulley so the matches. Suplus Center has pulleys and belts for short money.

[Bill Dufour]

If you do use a standard wall switch make it is two pole so it breaks both hots not just one. Good luck finding a 30amp switch for less then a used contactor.
Bill

[Curt Harms]

I must be looking at the wrong models. The Teco I spec’d out was $320.

http://dealerselectric.com/230V-sing...&GdPageSize=20

[andy bessette]

VFD is useless on a tablesaw. Replace the motor and resell the old one to recoup part of the cost.

[Tom Trees]

<p>

VFD is useless on a tablesaw. Replace the motor and resell the old one to recoup part of the cost.

I haven&#39;t read something I have disagreed with so much, for quite a while! You prob have a huge amp rating on your circut breaker,.... Me ? I have a 30a MCB with a 13a plug ...and around 40 feet of distance between them. I would blow the fuse every time if it were single phase motor...I can tailor the machine to whatever surroundings Im in. Even if you did find a second hand single phase 3HP motor (guessing the MCB in your consumer unit for the machine, has like over 80a?) I would keep the dual voltage (has it been stated?) 3 phase motor for another project. Thats my 2cents</p>

[andy bessette]

<p> I haven&#39;t read something I have disagreed with so much...

I'm simply heartbroken.

[Geoff Crimmins]

http://dealerselectric.com/230V-sing...&GdPageSize=20

While a table saw won't use the variable-speed feature of a VFD, and VFD will work fine as a phase converter on a table saw. I have a friend who put a VFD on an 8" Powermatic 60 jointer that has a 3-phase motor. Works great.

--Geoff

[Don Jarvie]

Will the VFD provide the full 3 hp or less? If it doesn’t give the full 3 hp then it’s worth the motor swap.

[Tom Trees]

Yes it will, I have been ripping iroko at near full depth without any signs of being underpowered

[Mike Henderson]

Will the VFD provide the full 3 hp or less? If it doesn’t give the full 3 hp then it’s worth the motor swap.

A VFD will operate a 3 phase motor exactly the same as if you hooked it to 3 phase power from the grid - as far as HP is concerned. It will also allow you to vary the speed.

VFDs provide three phases, each at full voltage and current. it is not like some of the workaround "phase converters" which only provide two phases and thus the motor does not provide full HP.

Mike

[Bill Dufour]

Make sure the motor and vfd are rated for the same voltage. If your motor is like 440/680 volts it will be cheaper to replace the motor.
Bill D

[Matt Day]

VFD is useless on a tablesaw. Replace the motor and resell the old one to recoup part of the cost.

Seriously? For one thing a bit of motor breaking is a nice feature on a table saw. Also 3 phase motors are bomb proof. It’s also a lot cheaper to add a vfd than buying a Unisaw specifically motor - PM66 motors are cheaper since they aren’t specific.

[Tom Trees]

I must say I dont have much breaking on my motor, I think I programmed 7 seconds ...
must look at the parameters I set again. (on a wee sheet somewhere)
I read that you should be aware what way the arbor nut tigthens, as it may come loose if you stop the saw too quick !!!
On my Startrite saw, the arbor nut tigthens the opposite way to the other Italian saw I have .
Can this jam the nut also ???

I haven&#39;t tried to test the Isacon/Askpower drives built in breaking I have BTW
The Isacon/Askpower has no terminals for a breaking resistor also, and the Huanyang has terminals,
but needs components soldered to enable the resistor to work,...
Theres a funny thread where someone used a hairdryer for this!

It might be wort looking up Wadkin Temple Jacks ones on youtube, if your looking for a VFD
Tom

[Mike Henderson]

Seriously? For one thing a bit of motor braking is a nice feature on a table saw. Also 3 phase motors are bomb proof. It’s also a lot cheaper to add a vfd than buying a Unisaw specifically motor - PM66 motors are cheaper since they aren’t specific.

Matt hit the nail on the head. About the only thing that can go wrong on a three phase motor is the bearings fail. Single phase motors have problems with the starting capacitor and the centrifugal switch - a lot more often than bearings.

This is assuming you don't overload the motor and burn it out, of course.

Mike