New guy here with some questions about speed control.
I am helping a friend get his R2/Boss8 mill working in exchange for some time on it. The problem is that the spindle only turns at 500 RPM regardless of the position of the hi/lo lever or the speed selected from the console (or from G code). No error messages are ever displayed and the rest of the machine works flawlessly. He was told by a tech some time ago that the tubular shaped proximity switch located within the Hi/Lo selector mechanism (top RH side of the head) was defective. A $500 replacement part from Bridgeport was deemed too expensive, and the mill has just been sitting.
I have a couple of questions -
1. Does anyone know what kind of detector it is? A simple magnetic switch, or an inductive type detector? There are 3 wires leading from the detector itself into the control panel which leads me to think it's some kind of electronic device rather than a simple magnetic switch. I'm sure I can find an alternate source for a replacement, but there are several different types to choose from. (ie http://www.balluff.com/Balluff/us/Pr...w/?menuLevel=1 )
2. Does anyone know what the detector is sensing, or how it functions? After removing the sensor from the linkage, and then selecting Hi/Lo, it's hard to tell what it is sensing as there is very little physical movement of parts other than the shaft that rotates about 180 and makes the gear change in the head. I can't see anything that appears to be magnetic so it must be sensing the proximity of something that I haven't yet seen.
3. Is anyone familiar with the circuit? I'm looking for troubleshooting techniques that can isolate the problem to the sensor.
One last point. The mill runs at 500 regardless of whether the sensor is physically installed in the shifter, or removed. I have not tried disconnecting the wires inside the control panel.
All answers, suggestions, ideas are most appreciated.