March's Motion Ideas and Tips

【Application】Tension Control with Torque Motors

Torque motors are ideal for winding and unwinding type applications. A torque motor can act as a brake when back-driven or a simple device to provide tension. Depending on the torque setting, the motor will provide tension to the material while automatically taking up slack in the line.

How does it work?

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In addition to tension control, torque motors can also be used for certain stamping and pressing applications when coupled with a linear device.

How do you size a torque motor?

Application Requirements

Motor Sizing Calculations

Max Diameter = 12”
Min Diameter = 4”
Max force per material = 32 oz Force
Speed = 4” / sec

Tmin = F * (D / 2)
Tmin = 64 oz-in

Tmax = F * (D / 2)
Tmax = 192 oz-in

Vmin = (4” / sec) * (rev / {4” * pi}) * 60
Vmin = 19 RPM

Vmax = (4” / sec) * (rev/ {12” * pi}) *60
Vmax = 6.4 RPM

If gear ratio = 15:1
Tm = (Tmin/max) / (15) / (81%) (gear efficiency)
V = (Vmin/max) * (15)

Then motor torque {Tm} and speed {V} will be:

Tmin = 5.3 oz-in at 285 RPM
Tmax = 15.8 at 96 RPM

Consult the torque speed chart above. The results appear to fall within the specification of the motor when looking at the 60VAC or below curves.

0.125 Nm = 17.7 oz-in
0.05 Nm = 7.1 oz-in

Recommended Controller + Motor + Gear Ratio:
TMP-1 + 5TK20GN-AW2U + 5GN15KA

【Engineering Note】What is Modular Automation?

Our Engineering Notes blog is a collection of motion tips, application examples, and trending topics in motion control.

Modular automation is the next phase of factory automation where the same production line is separated into modules and can be quickly reconfigured for different needs.

We're ready for this trend. Are you?