[CH33]

I'm looking for a solution to fix a clunking noise when I manually move my z-axis. I have a G0704 Grizzly Mill that has been converted to CNC with a G540 Gecko Drive. I believe the noise is caused by some backwards current being produced from spinning the motor because if I disconnect the motor from the Gecko drive the noise disappears. I have attached a video of the noise when the motor is connected to the G540. Here is the motor used on the z-axis: https://www.automationtechnologiesin...l34h295-43-8a/

[Jim Dawson]

Two possible fixes:

1) Mechanically disconnect the motor when operating manually.

2) Use a 4 pole switch to disconnect the motor electrically when using manually.

[CH33]

Hey Jim,

Thanks for the reply. I like the idea of the switch. I wonder if there is an electrical component that will create a diode when the motor driver is off. Even if there was it might take more time than it is worth while a switch is simple and easy.

[Jim Dawson]

Hey Jim,

Thanks for the reply. I like the idea of the switch. I wonder if there is an electrical component that will create a diode when the motor driver is off. Even if there was it might take more time than it is worth while a switch is simple and easy.

A four pole relay would work, but I think you would want to apply power to energize the relay before applying power to the drive, and shut down in the reverse order. You don't want to connect/disconnect the motor with the drive powered up.

I mechanically disconnect mine, have a lever that disengages the gear drive. But that won't work in your case.

[CH33]

I'm going to try out a 4 pole switch. I think an easy improvement to the Gecko driver would be to have diodes to prevent this. I contacted the Gecko technical support about this issue yesterday so I will post if they tell me anything useful. Thanks Jim.

[CH33]

For reference if anyone else ever has this issue; Gecko finally called me back and the designer of the Gecko drivers explained how to avoid this. He said that if I turn the power supply on and trip the emergency fault switch that power will still be applied to an H-bridge inside the driver and wouldn't allow current to flow backwards when using the mill manually. I have verified that this fixes the issue.