In case anyone might be interested, I mentioned on IRC some issues I had with a blown out unipolar drive:
http://www.wallacecompany.com/machine_shop/Shizuoka/00001-1a.jpg http://www.wallacecompany.com/machine_shop/Shizuoka/Bandit_Stepper_Driver.png http://www.wallacecompany.com/machine_shop/Shizuoka/Shiz_TIP36-1a.jpg (Darlington = two xstrs on one mini pcb, TIP36C PNP pair on high side for PWM current control on AA and BB, TIP35C NPN pair on low side for motor coil stepping on A1, A2, B1, and B2) I got the last of the parts yesterday and installed them to the Y drive and it works fine now. Unfortunately, the Z drive went out while testing. This time I knew what to look for and had spares, so I repaired the Z drive in short order. I hope there isn't another issue causing these drives to go out. It seems that a transistor shorts out, taking the other high or low side transistor out, then the fuse. On the other hand, if there was an overload from the motor, I suspect just the fuse would blow. (BTW, TIP35/6 = 25A, Fuse = 12A Fast Blow) In looking at how Darlington transistors work, I'm surprised that two of the same transistors are used for the first and second stage (hFE = 1600). I suppose transistors are cheap enough that there are no savings in using a smaller transistor for the first stage. If another transistor blows out, I may try a modern single module Darlington like these: http://www.digikey.com/product-detail/en/2SD2083/2SD2083-ND/3661817 http://www.digikey.com/product-detail/en/2SB1383/2SB1383-ND/3929429 (hFE = 2000, one high side, one low side) Although, I really don't want to put much more effort into these old drives. Plus the circuit traces are pulling up when I remove the old parts. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/ ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
