3ph Motor Install, Need Recommendations

lol, again with that, I know that motor is a lot, but its what I have, and I will not be purchasing any other motors for it. forget the HP number, its a 3ph .5hp motor now, what would you do with the pulleys, being that I DONT have good stock pulleys, and with VFD control can get away from most but NOT all belt changes..... but I don't want to buy stock type pulleys, I want different pulleys, the motor will not have steps, but the countershaft can have a max of 3 steps, or maybe, just maybe the motor has 2 steps, for hi and low, and the countershaft has 2 steps for hi and low, with the freq control to make up the rest.....
 
oh yeah one more thing, VFDs have an amp output limit control.....
 
True. But you said that you were going to have to butcher the cabinet to install the huge motor. The Commercial cabinet is pretty strong but it won't be if you cut half of the right wall out. I'll bet that if you got on CL and said that you had a 1-1/2 HP 3 ph motor that you were willing to trade for a 3/4 HP 3 ph one, you'd quickly enough get a taker. It's your machine and you can do whatever you want to it. But using that motor just makes no sense.
 
I'm in alaska, most people see or hear 3 phase and run lol. I'd only have to cut the cabinet if I chose to use the stock motor pulleys cause they stick out kinda far away from the cabinet wall. That why I mentioned using a deep dish pulley in an earlier post as it would move the motor over several inches, or I could run the motor shaft out the side of the cabinet, where the big pulley is at... no cutting.
I'm not interested in what anyone else would or wouldn't do, I'm only interested in the pulleys, and sizes YOU would run given you had this motor to install and there were NO other motors
 
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OK. Now I understand what you meant by "deep dish" pulley. If you do that, before you install the pulley, you need to "remote" the oiler as it is just barely accessible as it is. As an out of place afterthought, hanging that heavy a motor 'way in the back of the cabinet is going to be "interesting" (no room for a helper). So don't forget to install the motor pulley before you start installing the motor the FIRST time.

What is the motor's shaft diameter? What is the motor's maximum continuous duty rated RPM? What is the motors minimum continuous duty rated RPM @ 1/2 HP?
 
Not sure on the rpms, the power graph from Baldor says it makes 0% of rated output at 1700rpm, and 150% @1735rpm, the rated speed is 1755rpm I have a hard time believing that I would be able to stop it by hand at 1700rpm since the graph says it would be making zero hp..., it has an .875-.8745 (7/8) shaft. 145TC frame, flange front mount or foot mount TEFC
The motor on my mill doesn't seem to care all that much when I've cut with it at half rpm/hertz
 
chevydyl said:
Oh yeah, I also have a 1.5hp DC high torque treadmill motor I could use, it has about a 5000rpm range, problem with that motor is it has a screwed on pulley, that's a serpentine type belt drive, that's my other option, I could use that instead of the 3ph motor. I think that one would need some underdrive pulleys to use so I would stay in the range of lathe speeds, with some extra speed for polishing or whatever
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Chuck up the screwed-on pulley and turn it into either a V-belt pulley of the proper size or an adapter to put a v-belt pulley onto. If the fan is integral with the pulley/flywheel use a muffin fan to cool the motor. If you use either a multigroove or 3/8" cogged belt you can put quite a small pulley on the motor.
 
There must be something wrong with the graph. That makes no sense at all!

The maximum rated RPM is needed because at some point it's going to fly apart from centrifugal force. The minimum is needed because the slower it runs, the less cooling the fan will provide. You don't want to burn it up. On the plus side there, you don't need to get but about 1/2 HP out of it.

Without those numbers, I can't say which would be better but where I was headed was this. If the motor will run safely (not overheat) at 575 RPM, and you use two pulleys the diameter of the faster set on the 2-step motor and first countershaft pulleys, with the speed controller set to run the motor at 1725 RPM the 4-step cone pulleys would give you the four higher speeds shown on the chart on the lathe. With the motor set to run at 575 RPM, you would get the four slower speeds. I seriously doubt that the motor will safely run at 5175 RPM, which would be the other option of those two.

Or, once you know how fast you can conservatively run the motor, you could re-do the speed chart and go for something in between.

But in any case, a hollow (deep dish) pulley is by far the best way to solve the motor mounting problem.

Back to hanging the motor, and its weight, when I originally set mine up in 1982, I hung the 3/4 HP TEFC the hard way, holding the motor up with one hand. But that was soon to be 35 years ago. I don't recall why at the moment but last year I decided that I needed to slightly reposistion the motor. So I made a saddle of wood that I bolted to the top of a scissors jack and used that for all the heavy lifting.
 
The motor is way oversized, which is actually to your benefit (and quite common with VFD equipped lathe/mills which usually have a 10 fold operating VFD speed range usually with 2 manual speed ranges Lo/High) as you will have rated Hp output that you had before at much lower RPM. You should have full toque down to at least 15Hz or lower. Since the motor is way bigger than you had, it is very doubtful that you will have any cooling issues with the motor even running at 10-15Hz (300 RPM and above). TEFC motors start to have cooling issues at speeds below 15Hz and over 90Hz, possible exception might be running it at full load continuously, not going to happen. I do not know the safe upper speed for on this lathe, probably something under 2000 RPM. I would determine the pulley sizes based on the maximum expected RPM you want to achieve with the motor at 90Hz or approximately 2500 RPM (this is a safe and acceptable upper bound for the motor per most manufacturer's for this type/size of motor). You need to determine the lathe maximum safe operating speed and then work out the pulley ratios.
 
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chevydyl said:
Not sure on the rpms, the power graph from Baldor says it makes 0% of rated output at 1700rpm, and 150% @1735rpm, the rated speed is 1755rpm I have a hard time believing that I would be able to stop it by hand at 1700rpm since the graph says it would be making zero hp..., it has an .875-.8745 (7/8) shaft. 145TC frame, flange front mount or foot mount TEFC
The motor on my mill doesn't seem to care all that much when I've cut with it at half rpm/hertz
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I think those numbers are for 60Hz operation. Zero doesn't make sense but the other numbers are reasonable. Do you have a link to that table?

[Edit] If the graph you have is like the one posted by mksj you aren't reading it correctly (It's admittedly confusing).
 
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