I’m getting towards the end of my DIY CNC build and I’m having trouble getting my spindle to run. When started it turns probably less than an 8th of a turn then stops and has a resistance if you try to turn it by hand until I stop the VFD. The display on the VFD with show a small Hz rating for a split second as the spindle twitches before going to 0 and output current is displayed as constant 5.9A.

https://youtu.be/yG2R5bPUDbA

I have purchased a 800w G-Penny water cooled spindle rated at 220 volts, 400Hz, 4A and 24,000rpm. To run this I’ve chosen an Invertek Optidrive E3 230v 1ph to 3ph drive rated at 1.5kW and 0-500Hz control range.

I’m using a 4 core SY shielded control cable to connect the drive and motor with pins 1,2,3 to U,V,W respectively at the drive and pin 4 and the shielding both to the earth (pin 4 is connected internally and grounds the entire machine).

I’ve connected a wire linking terminals 1 and 2 to act as an enable switch and all other terminals are empty. Then I’ve configured the basic parameters as:

P-01 Max Speed = 24000
P-02 Min Speed = 6000
P-03 Acceleration Time = 3.0
P-04 Deceleration Time = 3.0
P-05 Stopping Mode = 0 (Ramped Stop)
P-06 Energy Optimiser = 0 (Disabled)
P-07 Motor Rated Voltage = 220
P-08 Motor Rated Current = 4.0
P-09 Motor Rated Frequency = 400
P-10 Motor Rated Speed = 24000
P-11 Low Frequency Torque Boost = Default rating dependant.
P-12 Control Mode = 1 (Keypad Control, Single Direction)

I believe the cable connections to be fine as I get almost identical readings if I measure the resistance between phases at the motor with the plug removed or at the drive via the spindle power cable. I’ve got 3.8 – 3.9 Ohms between all three phases and less than 0.7 Ohms from ground to any point on the CNC machine including spindle.

Also with the power off the spindle rotates freely by hand so I haven’t over tightened the clamp, it only gets hard to rotate when powered up.

Any help greatly appreciated. Thanks.