That isn't a particularly big servo. Much bigger servos are available. For example the brushed DC servos on my router are rated at 8.5NM continuous at 10A, 50NM peak at 60A (ISTR the drives are limited to around 30A). They are 1:1 drive onto 25mm pitch screws. Brushed DC servos tend to be lower revving/higher torque than brushless servos. They also usually have a higher peak torque. For instance those motors you linked have a peak of 3x continuous while my router's servos have a peak of 6x continuous. I have worked on machines with servos rated for 10kW or more (used as lathe spindle drives).
To replace steppers you can usually get away with a servo having a peak torque around 3/4 the stepper's holding torque. This is because stepper running torque is a lot less than it's holding torque and you can never run a stepper near it's maximum torque without risking lost steps. NEMA 42 steppers generally can't run very fast so doing a 1:1 replacement will require an over sized servo for the application, unless you want your machine to move much faster. Those servos are rated at 3000rpm. Work out how fast your steppers spin at max speed and work out the ratio. For example a 3:1 single stage belt reduction would give plenty of torque from those motors with a max speed of 1000rpm. Belts have negligible backlash and are fine for all but the most precision applications. Trapezoidal belts have slightly less backlash than HTD types. Les On 25/01/2017 09:07, Klemen Živkovič wrote: > I just checked: > http://www.automationtechnologiesinc.com/products-page/ac-servo-motors/the-ac-servo-driver-ac-servo-motor-400w-set > > to replace my 12Nm steppers - the torque on this motor is 1.27 Nm (they > rate is as high torque servos) - and is not near 12Nm, that my nema42 > steppers now provide. > Guess I need gearbox but this would introduce backlash - or there are some > brushless servos with around 12Nm torque available? > > Any ideas who can provide 12Nm servos if they exist at all? ------------------------------------------------------------------------------ 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
