On Monday 07 May 2018 22:56:15 Gregg Eshelman via Emc-users wrote: > The MC1650LS motor controller looks like a decent alternative to the > MC2100. It's newer and smaller yet is used with the same types of high > volt DC brush type exercise equipment motors. And prices are lower. > > Problem is I can't find diddly on connection diagrams or what sort of > extra bits are required to control the motor speed. With the MC2100 > there are many schematics out there for building a control circuit.
I've tried to use such,but not very satisfactory. They are scr/thyristor based controllers, meaning their response to loading or control signals is too slow for real control due to the effective switching speed of the drive being tied to the powerline. And most important is the fact that the control input is directly connected to the high side of the AC powerline, so the whole input circuit has to be isolated by something like a mesa spinx1. Any connection to anything else destroys the input circuit. The analog input from the spinx1 MUST be sent into the terminal that would be connected to the arm of the speed control thru a 10k to 27k resistor as that input is the summing junction of the feedback, and w/o the resistor, speed control is very very non-linear. In short, if you want real, linear speed control, scrounge up enough stuff to make a power supply that can source 125 to 130 volts and 20 amps surge, and use one of Jon's Pico Systems pwm-servo amplifiers. You'll have to cobble up two signals in your hal file, one of which needs to be 12 volts. I have a 90 volt 1 hp treadmill motor on the 7x12 running on about 107 volts so its probably making around 1.2 hp. Using one of Jons pwm-servo amps set for around 14 amps peak. And I am using a similar setup, with a 126 volt supply to drive the 90 volt, 1 hp OEM motor on the G0704. Its able to reach 3000 revs now from a former limit of around 2225 revs, but the practical limit is around 2900 as that motor has a resetable thermal limit buried in the windings. In high backgear and 2k revs, reverseing time is well under half a second, so its used heavily for rigid tapping. Current limit is set to about 16 amps. Both will make the motors chirp when the amps current limit kicks in. I might also remind you folks that the treadmill motors all have a pound or more in a screwed onto the motor shaft flywheel, which is also the polygroove belt pulley, that will unscrew itself if some means to lock it to the shaft is not done. Thats a pain, and has destroyed the shaft of a perfectly good motor. So there is a bit of hal trickery in the lathes hal file to stage and slow that reversal to try and keep it from screwing up the 2nd motor, and to reduce the strain on the drive belting cogs. If there is anything I've learned from that strong a motor, and that fast a control, its that the rest of the 7x12 spindle drive train is fragile. And a fast reversal is a sure way to break something. With a 5" 4 jaw chuck for a flywheel, rigid tapping is possible with the tap in the toolpost, but the turnaround overtravel distance needs to be programmed for an earlier reversal if the hole is blind. Spindle speeds for tapping, because of the overtravel, need to be held below 200 rpms. I have some hal stuff to measure that overtravel in both machines that I can display with a halmeter. But it outputs in encoder counts which need to be converted to distance by hand. Jon's pwm-servo amp is a full 4 quadrant controller. You can get very fast stops by programming an s25, g4p.15, m5 from an s2000 run. Just an m5 is a total shutdown and it coasts, but set it for very slow for a fraction of a second and you get a whump stop NOW! The scr/thyrister stuff works for slow control, but is dangerous to hook up. if you want good, instant control, the pico pwm-servo is the magic twanger up to 2 or maybe 3 hp. But be sure and tell Jon it will be driving a spindle so he will change the toroids used. -- 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) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
