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stepper motor not delivering expected torque.

Hello,

We have a NEMA-23 a stepper motor from there:

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270 oz/in Model # RHT23-270 rated at 2.48 V and 4 amps.

and we are using a stepper driver FT-3 from there:

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the FT-3 driver works for unipolar motor, so I am really expecting

1.35 Nm (190 oz-in) torque for the motor mentionned above. Yet, when we implement this solution ( a power supply of 5 V and resistors of .6 Ohms), we barely get 1/10th of that torque. What are we doing wrong ?

Jake.

Reply to
Newbie
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A couple of points.

  1. A stepper motors torque is rated while it is stopped. The faster it turns the less torque it has because the coils can't charge fast enough.
Reply to
Dan Mauch

Dan, Thank you,

I understand for the torque curve showing a decreasing slope, so that indeed when it turns, the motor cannot have the max holding torque. Yet, we are talking about relatively slow speed. Irrespective I see you point.

Now to the second one, what do you mean we need to ballast resistors: increase resistor size ? If so I can show my calculation so that everybody can get a lesson out of our initiation in this realm :-)

Jake.

Reply to
Newbie

Do you have a current reading from your powersupply? Lots of supplies have current limits. Be sure you're really getting 5V at 4A before jumping to conclusions.

Reply to
Randy M. Dumse

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