mach 3/boss 5 spindle shuts off by itself, will only run a few seconds

I I was having trouble getting the spindle on my machine to run and as recommended pulled the fuse behind # 14 optoisolator. spindle ran fine without the fuse in. I replaced the opto on #14 and now am able to run the spindle for just about 15 seconds or so and then it automatically shuts off. On MDI, m3 calls for spindle start, I manually start the spindle and mach runs the delay macro, then the spindle shuts down shortly thereafter. anyone know what might be wrong? there is no load on the spindle and the brake is off- it spins freely by hand so I suppose mach is turning it off, but I'm new to mach and not sure what I'm doing...

any ideas?

tom

Hello Tom have you tried the oil reservoir to see if it's level has gone to low and the float switch has come into circuit, this will shut the machine down as it drops out one of the relays. Best of luck Colin

Generally the oil being low will make it not start at all. I have had similar problems on mine. First thing I would check is the wires for the Z axis limit and home switches. I have had trouble with them moving around when the z jogs down and stopping the program. They are just behind the cover on the front of the head. Make sure the wires are all tight and not abraded where they could be shorting.

If that doesn't help, I would look around for other dirty connections or loose wires. When the spindle turns on, the vibration may make a connection jitter a little and cause a spindle fault.

Good Luck
Matt

Its not the machine, it is mach or the BOB, and/or me not knowing what I'm doing. With the fuse pulled on the BOB the spindle works fine. There is oil in the oiler, and bypassing the low oil switch has no effect.
t

if the motor has a drag ob it , it maybe over heating and tripping the heat contacts inside the motor , the bearig between the motor v-drive may be corruptand ausing the drag,, thats just my take, it maybe el;ctric, i hope you find a competent repaireman,

Then I would look at noise issues.

Does it estop mach when the spindle stops? If so, it could be a noisy input causing mach to estop which turns off the spindle. If this is the case, try increasing the debounce on the inputs and possibly add a .1 uF capacitor across the two wires of each input.

Which BOB are you using? Hillbilly?

Matt