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steppers (x4)

Jan Cumps

Can you have enough stepper motors? Maybe.

I did an investment. I had one driver IC and a good motor. I added 4 somewhat heavier motors, and 4 Allegro A4988 drivers.

image

(for my own documentation)

  • Motor Type: Bipolar Stepper
  • Step Angle: 1.8 deg.
  • Holding Torque: 40N.cm (56oz.in)
  • Rated Current/phase: 1.7A
  • Phase Resistance: 1.5Ohm±10%
  • Insulation Resistance: 100MΩ¸ Min, 500VDC
  • Insulation Strength: 500VAC for one minute
  • Physical Specification:
  • Frame Size: 42 x 42mm (1.7 inch x 1.7 inch)
  • Body Length: 40mm
  • Shaft Diameter: 5mm
  • Number of Wire Leads: 4
  • Wire Length: 400mm
  • Weight: 280g
  • Temperature rise: 80deg Max(rated current, 2 phase on)


Rood B+
Groen A-
Zwart A+
Blauw B- 

image

One more strange stepper is on its way from China:
image, 

Goal is to control them with a single Pico.

  • in reply to obones

    Hello on the gantry crains i have worked on they 2 motors running in parallel, 

    compaired to the CNC plasma machines that use 2 drives for 2 motors  (maximum deviation of 1mm) across 8m

    using rexroth motors and drives with both drives feed back to plc

  • in reply to acdc90

    I think they are not stepper motors, I guess? Are they induction motors or something else for the gantry crane for instance, or servo motors?

  • in reply to shabaz

    The advantage of driving both sides of a gantry is not that you get more force but that applying the force equally to both sides massively reduces the demands on the sliding bearings.

    On a big gantry it's probably essential.

    Probably the best (cheap) way to do it is a motor driver per motor with a single controller (which doesn't need to know there are two motors).

    (For cheap read open loop stepper motors !)

    MK

  • in reply to michaelkellett

    Makes sense.. I was commenting on Steve's question regarding the possibility of doubling up the power before @obones menrioned gantries, which would have that requirement for the bearings as you mention.

    I wonder if slight inductance differences would cause some amount of losses or vibration if each end was driven from a geared down stepper, since each burst of rotational force may occur with slightly different amounts at each end (which led me to wonder what types of motors are actually used for such a purpose). I don't really understand motor characteristics, nor mechanical systems much in general at all though, so I probably have some naive thinking here.

  • in reply to obones

    I'd say: single logic / control part - and wire them so that they turn in the opposite direction.

    You may have to beef up the power part of the driver. For a TI DRV8711, it would mean other power MOSFETs, for an integrated driver, you may have to shop for one that can deal with higher current (and voltage headroom).

    Or a driver per motor, using the same logic STEP signal

  • in reply to acdc90

    Thanks, I wasn't in the same ballpark in terms of span, it's more of an idea about reusing inkjet printers mechanical parts to create a "home made" plotter or laser engraver.
    But that's something in a corner of my head, not even close to starting

  • in reply to obones

    A scanner that I took apart, had a single stepper (with reduction) for the scan wagon. And a toothed belt that interacted with cogwheels at both sides of the scanner. So the force was equal on both sides, but the rubber gave a bit of mechanical leeway.