Micromill running sporadically

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Benny
CNC Expert
CNC Expert
Posts: 201
Joined: Fri 20 Oct , 2006 15:27 pm
Location: USA

Micromill running sporadically

Post by Benny » Wed 05 Nov , 2008 15:59 pm

Customer writes in....
The CNC Mill was running sporatically, and when the
school electrician looked at it, he said the switch and the motor were bad.
When I turn on the switch for the cutter, nothing happens. Please help!

Benny
CNC Expert
CNC Expert
Posts: 201
Joined: Fri 20 Oct , 2006 15:27 pm
Location: USA

Micromill running sporadically

Post by Benny » Wed 05 Nov , 2008 16:04 pm

Things to look at:
1. Possible faulty Rocker On/Off switch on the front panel:
Check across the terminals with a Volt/Ohm Meter (VOM) set on ohms.
Or, check terminals L1 and L2 on the spindle control card for 110vAC current when the switch is turned on.
2. Possible Bad fuse --- Install a new fuse.
3. Possible Faulty Guard Switch or Guard Relay:
4. Does the relay open/close when the guard is opened/closed?
5. Possible Faulty spindle speed pot:
6. Check across terminals with the VOM set on ohms.
7. Possible Faulty spindle control board:
Look for burned components or does it smell burned.
8. Possible loose wire:
Pull and/or tug on the wire connections, tighten as needed.
9. Possible bad Spindle motor:
The spindle motor is DC. The 110 vAC power has to go thru the spindle card to convert to DC. With the spindle switch ON, VOM set on AC Volts. Check voltage at the L1 and L2 terminals - 110vAC. VOM set on DC volts. Terminals A+ (positive, Red wire) and A- (negative, Black wire) up to 90 vDC, depending on position of spindle speed knob.

It would be a matter of testing the motor and the different components.

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