Hi all,
I posted this message on my build log here and Gerry (ger21) suggested I post it here also.
I recently bought a 3HP water cooled spindle and a matching VFD from here. It took some time but I managed to track down some proper, three core, shielded, control cable with 4 sq mm cross section conductors. 6 metres cost me £52 GBP!!! - expensive stuff but they sent me 8 metres. At 13mm diameter, this stuff is not easy to work with and my first problem was to try and solder the cable to the connector when the solder buckets were too small for the size of conductor. Eventually managed that OK, wire up the input cable, put in a temporary, gravity feed water tank and ventured to try the spindle.
First attempt was not good but after a couple of questions to the seller, to get some of the program data, all things looked good. The spindle whispers up to 24000rpm and there is absolutely no vibration whatsoever. I am truly impressed with this motor.
Next thing to try was to run the machine at the same time as the spindle and this is where I ran into massive problems. On start up of the spindle, the machine motors vibrate like mad and start to take off. This also happens as the motor runs down, just before it stops. The scary thing is that this also happens when the Gecko drives are in the fault condition and no computer attached. I did not think it was possible for this to happen as I have a charge pump attached to the controller. On careful inspection, the relay on the charge pump switches on and off rapidly of its own accord during run up and run down of the spindle.
The plug for both the controller and VFD share a dual socket in the workshop and the workshop has two ring mains. Removing the VFD plug and plugging it into another socket, at the other end of the workshop and on a different ring, improved matters but there was still some interference.
An electronics friend of mine tried a couple of filters on both the VFD input and controller input but these made little difference also. He concluded that the noise was travelling down the ground lines and basically, getting everywhere on the mains circuitry.
Before anyone asks, all my cables and wires to the servos, encoders and limit/home switches are shielded. The shielding on the spindle cable is also the ground.
I am hoping that someone, looking in, can shed some light on this problem and offer a solution as I am sure I am not the only one who has had this problem.
Cheers,
Mike