My Cure For THe Powermatic 3 Phase Blues

[Dave Cav]

I am running two 3 phase, 5 HP motors with VFDs off of 220. One is a TECO FM50 3 HP model ($185 from Factorymation) which is on my Delta 12/14" table saw. I have been operating the saw with this VFD for a couple of years with no problems. It's set up for a 10 second ramp up and is good for 10.5 amps normal operating current, and will put out 150% for up to sixty seconds if necessary.

The other VFD is a TECO CV7300 7.5 HP VFD. This is nominally a 3 phase in, 3 phase out model, but it works fine with 220 input although the output will be derated, as discussed in previous posts. It is connected to my Powermatic 180 thickness planer, and again, it has been operating for about a year with no problems. I used a bigger VFD on the thickness planer as it is more heavily loaded than the table saw and I wanted to have the full 5 HP available for planing.

Let me know if you need more details, but I wouldn't hesitate for a second to reinstall the 5 HP motor and run it with a 3 HP VFD.

[Chip Lindley]

The 5 HP motor has a 184C mount. The 3 HP has a 145C mount, with a smaller bolt pattern(?) I think.

John

Old Parts List for a PM66 of your saw's vintage, shows FOUR different motors (two 2hp and two 5hp, in 1-ph and 3-phase models. All have a "TC" frame. The Parts List shows only one motor mount part.

From studying Baldor drawings, I surmise that 56C, 184C and 145C frames have 5/8", 7/8" and 1-1/8" shafts, respectively, but the same bolt pattern, with holes spaced 5-7/8" o/c. Same with the newer 184TC frame.