[How-To] Grizzly G0750G electrical cabinet

[jarhead]

I am curious how much of this electrical circuitry needs to be saved if i do a VFD conversion?

seems like it would be easier to gut the cabinet and start over so it all makes sense.

Currently it is 2HP single phase.

Thanks, Joe

 

[markba633csi]

All of it would go, unless there is a coolant pump relay in there somewhere

 

[mksj]

True you could remove most/all of it, but if you just are looking for a simple VFD install and do not want to figure out a new control system, you could remove the high voltage wiring to the forward and reverse contactors and use on set of NO inputs to trigger the respective VFD forward/reverse inputs. Even simpler is to snap on an auxiliary contact block with a NO switch to those two contactors and use that for the VFD run commands. No wiring changes needed, just direct connect your motor to the VFD instead of the terminal strip. That way all your controls working exactly the same inclusive of all the safety interlocks. There is one added wrinkle in wiring up a lathe with a foot brake is that the brake switch should be replaced with dual pole switches, one side (NC) maintains the current wiring, the other NO switch block is used to connect the VFD common/P24 to a programmed input for the free-run (base block) command. This way the VFD will not fight the foot braking when stopping the chuck.

 

[coolidge]

I will say this, I have found loose wires in more than one Grizzly electrical cabinet and cord grips gripping nothing but air (wrong size). Now I check every machine that comes in the door.

 

[jarhead]

True you could remove most/all of it, but if you just are looking for a simple VFD install and do not want to figure out a new control system, you could remove the high voltage wiring to the forward and reverse contactors and use on set of NO inputs to trigger the respective VFD forward/reverse inputs. Even simpler is to snap on an auxiliary contact block with a NO switch to those two contactors and use that for the VFD run commands. No wiring changes needed, just direct connect your motor to the VFD instead of the terminal strip. That way all your controls working exactly the same inclusive of all the safety interlocks. There is one added wrinkle in wiring up a lathe with a foot brake is that the brake switch should be replaced with dual pole switches, one side (NC) maintains the current wiring, the other NO switch block is used to connect the VFD common/P24 to a programmed input for the free-run (base block) command. This way the VFD will not fight the foot braking when stopping the chuck.

Thank you,
No foot brake on this model.
I have been looking at the schematic and am not sure of all the terminology yet. Trying to tell the difference between which contactor does what.

what is a NO input?
EDIT: Normally Open?

I've been reading other posts on here too so i learn more prior to tackling this.
Thanks, Joe