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Topic: Advice on higher torque Stepper please (Read 916 times) previous topic - next topic

nemo1966

Oct 13, 2012, 07:05 pm Last Edit: Oct 13, 2012, 07:41 pm by nemo1966 Reason: 1
Hi guys, started my first project with the Arduno Uno, Easy Driver and the sparkfun stepper. It was to open and close a heavy drawer automatically using the stepper and setting it's limits with micro switches. Also incorporating a switch on reset (if someone turned off the power whilst in the middle of an operation).

After putting it together it was a breeze to get up up and running, I come from a software dev background  :)

Now I am thinking I would like to beef up the stepper to a higher torque version.  With this in mind I was looking at http://www.ebay.co.uk/itm/180973950166?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_8359wt_1396 in conjunction with the Big Easy Driver http://www.schmalzhaus.com/BigEasyDriver/

Problem: I notice on the spec of the stepper that it states 2.8v and 1.68A... is that right? where would I find such a power supply and how would that work with the big easy driver? e.g is 2.8v too low to operate it?

*** EDIT: Im wondering if its 28v

thanks in advance
Nemo

MarkT

What you have there is a bipolar high-performance stepper designed for high torque and high speed.  They are meant to be driven from a high voltage via a chopper IC that keeps the average winding current constant (like PWM for motors but controlled directly from current).  With a high voltage supply the chopping acts as a buck-regulator (which is power-efficient) but allows lots of back-EMF and thus high rotation speed.

A typical driver chip would be the A4988 or L6208 or many others

You'll notice the motor has low winding inductance as well as low resistance - this allows high PWM rates (above the step rate).
[ I won't respond to messages, use the forum please ]

nemo1966

Thanks fo the reply.

Son instead of the big easy driver I should be looking at something like this? http://www.hobbytronics.co.uk/a4988-stepper-motor-driver-regulated

thanks again
Nemo

MarkT

Yup.  Or use gearbox and a smaller simpler motor?

The high performance motors are principally used in CNC positioning systems to give both high speed and high-torque, sounds rather overkill for opening a drawer.
[ I won't respond to messages, use the forum please ]

nemo1966

It's not as straight forward as opening a drawer, the drawer also lifts a panel and the sparkfun may not have enough torque.

Could you recommend a smaller simpler motor with a higher torque than the sparkfun?

thanks

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