[velocityxlrg]

Are there any published RPM vs. HP curves available for the 1100 series III? I've checked the Tormach website, the manual, and the factory test report, but I can't find any kind of graph or actual numbers.

[FuriousGeorge]

Not sure about the graphs, but I know that you get max torque between 2500 and 3000 RPMs (if you're in high). I would love to see the actual numbers.

[SCzEngrgGroup]

It's a 3-phase motor with VFD, which means it's essentially constant torque up to the motors base speed (which should be printed on the motors ID plate), and constant HP above base speed.

Regards,
Ray L.

[nitewatchman]

It's a 3-phase motor with VFD, which means it's essentially constant torque up to the motors base speed (which should be printed on the motors ID plate), and constant HP above base speed.

Regards,
Ray L.

That's a True Statement.

Now the question is, to rephrase it: What is the relationship between the HP and RPM at speeds below motor base speed?

Obiviously at 0 RPMs the HP also is 0 and at Base Speed (1800RPM I think) the HP is maxed.

I don't know either and would really like to see the answer or a chart.

Running my 1100 in the high speed range at 500 RPM and plunge cutting with a 5/8" end mill keeps the HP Meter bumping the yellow but the total machine current draw for everything including spindle, controller, display, drives, fans, lights, etc. is only 9.5A.

nitewatchman

[SCzEngrgGroup]

HP = Torque(ft-lbs) * RPM / 5252

So, if the motor is 1.5HP at 1800 RPM:

Torque = HP * 5252 / 1800 = 4.37 ft-lbs.

Using the first equation, you can calculate HP at any ROM below base speed. Using the second, you can calculate torque at any RPM above base speed, keeping in mind that HP is constant.

Unfortunately, motor ratings are pretty much best-case numbers, so what you actually see in the real world will generally be less. For a 1.5HP motor, I would not expect to actually be able to *use* more than 1.0 -1.25 HP under most conditions.

Regards,
Ray L.

[gjvander]

Let me know if I screwed this up.

[gjvander]

Just some numbers to back up what I plotted. I had a spectrum analyzer and an accelerometer hooked up my Tormach to balance the rotor in place.

The FFT showed two distinct peaks when for S5140 : 5227 RPM and 4298 RPM. The 5227 RPM is the spindle vibration, the 4298 RPM is the motor vibration.

4298 RPM / 60 = 71.63 Hz. The VFD is at 143 Hz for 5140 RPM (as read in cabinet display). 143 Hz / 71.63 = ~2, so I assume the motor is a 2 pole.

Installed pulley ratio is 5228 RPM /4298 RPM = 1.216.

Nameplate on motor says rated at 60 Hz. It actually lists 1715 RPM as spin speed for 60 Hz, but I am using the measured numbers.

Like Ray said above Torque = HP * 5252 / RPM. So Torque = 1.475 * 5252 / 1800 = 4.3 ft.lbs. x 12 to get to in.lbs = 51.64 in.lbs / pulley ratio because we are speeding up the spindle = 42.5 in.lbs @ 2190 RPM Spindle speed (1800 RPM motor speed).

Flame away...

Regards,

Geo

[BAMCNC.COM]

Cool!

[nitewatchman]

Cool!

+1

[Al_The_Man]

Nameplate on motor says rated at 60 Hz. It actually lists 1715 RPM as spin speed for 60 Hz, but I am using the measured numbers.
, so I assume the motor is a 2 pole.

That would be a 4 pole motor.
Al.

[TurboStep]

Check out the following post:
http://www.cnczone.com/forums/tormac...ml#post1257430

Quote "Thanks to Greg Jackson and Matt Doeppers from Tormach, and HSMAdvisor user (David C. Allen) who made a request, i was able to create Horse Power/RPM curves for Tormach PCNC770 and PCNC1100 models"

This might be what you're looking for. The source of the information should be reliable.
Step

[mrquacker]

Now what about the 770 and its 10k spindle?

[velocityxlrg]

Thanks to all for the info. FS Wizard Maching Calculator seem to have the actual data points I was looking for.