Posted by duncan webster on 04/04/2023 20:56:34:
From the info on the web it looks like a single phase induction motor, so you'll have to swap the motor. I wouldn't have thought it was worth the effort, and you will lose power at low speed.
That's down to implementation.
The recommendation for using VFD's for speed control I've had from ABB and others (when discussing pumping and material conveying applications) is thus:
- Purchase an "Inverter Duty" motor which is rated for a given power output (on a curve) over a given frequency range (this varies with vendor/design and includes options like 10-50Hz, 10-100Hz, 50-250Hz or even 40-400Hz for different types of constant torque and variable torque applications).
- You should base the motor selection based on it's rated Power at the RPM corresponding to the greatest highest power requirement.*
- Gear the motor drive so that your lowest required equipment speed is equivalent to your motors lowest rated frequency.
- If you need a very high gear reduction to achieve this use a 6 or 8 pole motor.
- Set the VFD parameters up so that it matches the frequency-power curve of the motor, accounting for the increased back EMF
They were very clear that you should not be running motors below their rated frequency.
Applying that to the use case here, a 40-400hz 4 pole motor with a fixed two stage 5:1 and 2:1 pulley reduction could give a speed range from say 24-2400rpm, which would be suitable for pretty much anything you might realistically drive in a MT2 drill spindle.
If you only do smaller work you might consider a different setup like buying a 50-250 Hz 2 pole with a 5:1 reduction to give 300-3000rpm.
*In our use case this would mean looking at the recommended metal removal rates for drills of various sizes in various materials, developing curves for power consumption and using those identify the point at which the highest power demand is and it's corresponding RPM, so you can match that to the motor's curve.
Edited By Jelly on 05/04/2023 12:34:33
Edited By Jelly on 05/04/2023 12:50:44