[slowlearner]

Good morning friends,
I have a 1992 4020 high torque mill. It hasnt been used over the past few years due to the economy. Our work load has increased lately and its time to bring the machine out of hibernation. I do need to give you a little history about this mill and the problem I have. A few years ago I had to replace the Mac solenoid valves with the Watts brand due to unavalibility. Since that time it was noted that the load meter would register in the red in both low and high ranges. Increasing the rpm to 150% would decrease the load on the meter. Not long after this the mill was shut down so nobody got around to working on it. I had to run this machine yesterday and noticed at the end of the shift that the spindle motor was to hot to hold your hand against.
I know now something is awry. I am the one who swapped the Mac's to the Watts valves is it possible I wired these in wrong or do I have another problem? I have lost touch with my go to guy for Fadals does anyone have
any ideas or been through this before? I thank you all in advance for your
knowledge and wisdom.

[slowlearner]

Update: I ran this spindle for 2 hours this morning in low range and everything is normal. Load registers around 25% and the motor is lukewarm.
So the hot motor only happens during high range. I was running the spindle at
2500 rpm yesterday and cutting wood when it got hot, so I wasnt overworking it. Any ideas?

[scadvice]

You said you were machining wood, sawdust in the motor could clog it and cause it to overheat.

Steve

[slowlearner]

I had not thought of that. I will blow some air through the endbell and see if anything comes out. I dont really believe in coincidence but the load meter
never registered above 40% until after the valves were changed. Is there
any way that it could be associated? Could I have wired the valves wrong?
Thanks for the reply.

[dksoba]

-Check if the belts are engaging/disengaging correctly by removing the head cover and switching between high and low speeds.

-Check if the hydraulic lines are filled with hydraulic oil (not air).

[zombie1363]

When running at 2500 rpm on the spindle, the spindle motor is maxed out at 5000 rpm.

Commanding S2501 will make machine shift into hi "gear" and motor will only run 1250 rpm and probably run cooler.

Checking for swollen or dragging belts is a good idea to. It should turn freely at all times and no chirps or "grabs" when spinning.