greetings & a happy new year to all; I finally figured I felt good enough to go out to the garage and see if I could resurect the 6040. When last putzing it I had left it with the machine motion to lights and coolant pump, and the mist pump disconnected from the 7i76 and was in between sessions in the cath-lab fixing my ticker.
One of this two was a dead short on the 12 volt field supply, and when I traced the wire to the lights & motor coolant relay, I found that I'd not installed a flywheel diode across that coil because I was out of a suitable diode. So I ordered a bag of 100 volt 4 amp diodes. While I'm keeping this chair warm, they came in, so I went out anc cut a 40" piece of light zip as that was more suitable, crimping a diode into the hiltchi sleeves, pulled thar relay loose and connected it, throwing other end toward the interface box. Moved the ladder and hooked the other end up. Cycled it from linuxcnc several tines, worked perfectly. Hooled up the mister motor power, worked as designed after a couple minutes to reprime the pump as it had a good month to bleed back. By then my legs are telling me they are going to give me hell for cramps in the night, I've been laying around too long. So thats the background. Question for Peter: Could the lack of that diode have triggered a substrate scr in the 7i76D?, crowbaring the field power, but which due to the supply trying to cycle, never got clear to zero volts to reset that invisible scr. It could only be healed with a full powerdown, which is the only theory I can come up with that makes sense. The same 7i76D output, with a flywheel diode seems to be running it flawlessly now. The supply is rated at 12 volts and 2.1 amps so doesn't (probably) have enough cajones to burn things up. All relays on, its a tad under an amp total. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
