[Poseidon]

Hi Doc,

Sorry to hear of your inverter woes. Thankfully, someone else is carrying the Sieg SX4 here in the US(Milling Machines) and at $ 300.00 less than Grizzly. Support from Grizzly is almost non-existent. I even tried contacting Sieg but they told me that I had to go through the distributor which, at that time, was only MTW in Canada and Grizzly in the US. My replacement has been working since its installation but I have always been using the POT to turn the motor down. Do you have a source for the transistors that sit below the main board?

BTW, is your unit already CNC'd? I ask because the E-stop becomes even more important with the conversion but, given the reliability problem with the inverter board, I have been keeping the keyboard handy for its Escape(Esc) key to stop the automated motion of the table.

[DrWiggly]

I do not have CNC connected.

See the update to my recent post. Grizzly has not forsaken me! In my discussions with Tech Support, we speculated that since the problem does not occur on most of the machines they sell, and since replacing the controller doesn't fix the problem, some other part of the machine has to make my unit different from most others. The "Emergency Stop" switch operates by simply turning off the AC power to the control unit, so the motor is the only other part that seems suspect.

The DC motor has Hall magnetic sensors in it to detect the rotor position and switch the power phases as needed. If the sensors were behind or ahead of the rotor a little or noisy or some other way not exactly right, that might do it. I'll post what happens with this experiment.

The power transistors used in the motor controller are mounted directly on the heat sink and their leads are soldered on the circuit board. They are Fairchild FGL60N100BNTD insulated gate bipolar transistors (IGBTs) and cost about $6.42 from mouser.com or many other electronic parts suppliers. It is important to remove the old solder to clear the holes so that you can slide in the leads of the replacements. I also replaced the insulating film between the transistor and the heatsink just for good measure.