Did I get a good deal on these Steppers? :)

[mrbasher]

Hi all,

I was out today at lunch foraging through the local electronics "surplus" store and found what looked to be some pretty nice stepper motors for $19 each...

Specs: http://www.linengineering.com/LinE/c...s/pdf/5718.pdf
Lin Engineering
Size NEMA 23
Model 5718L-04P
Amps 6.50
Torque 294.0 oz-in.
Step 1.8 deg.

From what I could find online they seem to be much more expensive than what I paid... I picked up three of them just because, but they must have had 20 or more of them there. I assume they are used, but they don't have a mark on them.

[Dorsal]

So, who did you get them from? Name? Address?
The voltage requirement to drive those motors in series ( 32 x the sqrt of the inductance) is 32 X (sqrt 1.3) = 36.48 V so power supplies and controller cards won't be an issue at all.

[ger21]

That's a good price, but the problem is that you'll need more expensive drives to supply the 6.5 amps.
Up to 3.5 amps, you can use a Gecko G540 which is about $75/ motor.
To get the 6.5 amps, you'll need a Gecko G201X which is $114/ motor.

If you buy a G540 with motors, similar power motors are about $40 each, but you get the G540 for $50 less.

So, bottom line, is if you already have the drives for them, it's a really good deal. If you don't have the drives, it would have been cheaper to buy a G540 and new motors.

[Dorsal]

Oh yeah - I forgot to look at the Amps / phase number.

[mrbasher]

Thanks guys

So is there any advantage to using a motor with a higher amp rating?

Also, the motors were at a place called Vetco in Bellevue, WA.

I might have a line on getting some of these: http://www.motionshop.com/pr/lineng-RMS2.shtml but I'm still waiting for the guy to email me back...

[H500]

A high amp motor is not as good as a low amp one of the same torque because you will need a more expensive driver.

[RomanLini]

Higher amp motors also have significantly lower inductance and will be more prone to resonance problems when used at low speeds due to the much higher excitation energy per step.

I would consider anything more than 3A/phase in Nema size23 as possibility of being problematic motors at low speeds. Those motors may have even been sold off as surplus because of resonance problems.