Stepper Motor Question

Very likely, but be sure the stepper doesn't try to draw more current
than the L293D wants to provide.

A Google search for 'l293d bipolar stepper' turned up up the following
on the first hit. Looks pretty promising:

http://mechatronics.mech.northwestern.edu/design_ref/actuators/stepper_drive1.html

-- Gordon

The spec sheet for the stepper says the 35L048B1B-N is 5V bipolar with 11
ohms resistance per winding which I calculate as 454 ma (5/11) (not
counting voltage drop in the driver), and the L293D says good to 600 ma.
Is that all you need to do to calculate the current requirement of a
stepper when the spec sheet doesn't give a current rating?  Or are there
other issues to think about?

--
Curt Welch                                            http://CurtWelch.Com/
curt@kcwc.com                                        http://NewsReader.Com/

I didn't bother looking at the spec sheet, but actually, a lot of people
"over-volt" steppers to get more torque out of them. That increases the
current obviously. But the L293D is stackable (so they say; I've never
done it), to increase current rating. Lots of things to play with.

Steppers are seldom *ideal* motors to use unless you use fancier driving
techniques, like current chopping. Then you get into all kinds of design
parameters for the drivers. So the correct answer to the original
question, other than "42," is "maybe."

-- Gordon

Consider using the SN754410 which is pin compatible with the L293D,
but has almost twice the current capacity.

It might be prudent to measure the actual coil resistance of a few
of the steppers before totally relying on the spec. sheet.  Sometimes,
the manufacturer changes the manufacturing process (changes wire gauge)
without updating the spec. sheet.

-Wayne

IMHO you can't make any sense of a stepper motor spec
without a speed against torque graph, stating volts and
current. If the supplier doesn't plaster it all over the
advert then it's usually fairly safe to assume it's a bit
naff. If they give you a 'holding torque' but no 'pull in
torque', you know it's a disaster.

So the qualified answer has to be, 'Yes, if your application
does not require any kind of speed'.

Steppers come in 2 flavours when you start talking speed.
Those with high impedance coils designed for constant volts
and those with low impedance coils designed for constant
current.

The problem with the constant voltage type is the high
impedance of the coil. You can't switch it very quickly so
the power falls away like a lead balloon very early on in
the speed torque curve.

The constant current type work with LOTS more volts than the
coil is rated for. Impedance is overcome by volts so they
can go much faster before you reach the lead balloon part of
the torque curve. The problem is the extra circuitry
required to control the current.

These steppers are by Portescap, but not their fabled disk
magnet technology which makes for some of the fastest
steppers in creation :o)