Kirk Wallace wrote: > I am thinking about building amps to replace my Bandit stepper amps: > > http://www.wallacecompany.com/machine_shop/Shizuoka/00001-1a.jpg > > http://www.wallacecompany.com/machine_shop/Shizuoka/Driver% > 20Schematic1.jpg > > The motor supply is 45 Volts and I am shooting for 10 amp output. The > input will be half-step quadrature. I am thinking about using an HIP4080 > for the core of the design: > Be VERY cautious of this chip! After using it in my first servo amp, and having a lot of trouble with them blowing up, I called Harris and got hold of the applictions engineer for that chip. He assured me that I was doing better than any other customer, as I was getting nearly reliable operation at 59 V, while no other customer had ever succeded in running them above 54 V. (This is for a chip boldly advertised as good to 80 V on the DC bus, 96 V on the high-side bootstrap voltage!) Oh, well, that was GREAT news. He advised a whole bunch of crazy schemes to isolate the chip from transients, but in the end agreed all that would give me 4 or 5 more volts.
If you supply is a very stable 45 V, it might work. But, after all, it is a synchronous-antiphase driver, and will cause a lot of iron heating in the motor. With only a little more work, you can use a REALLY solid chip like the IR2113, never have to worry about voltage, and build a sign-magnitude drive that will likely run the motor 30 C cooler. > > or should I invest my time in another bridge driver? > > Also, I suppose that if I have a fast enough PWM source, I could get EMC > to micro step? > Sure. Once you have a current control loop for each phase, microstepping is pretty trivial. But, unless you put in a system for damping mid-band resonance, you will still have a mediocre driver. My personal strategy if I was going to make a 10 A microstepping driver for myself (not as a commercial product) would be to buy some Gecko 201 or 203 drives and change the transistors and current sense resistors. Basically 10 components to change, and instant 10 A driver with about the best characteristics you could imagine. Jon ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
