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Springs - What is a Negator Constant Torque Spring Motor

The Neg’ator constant torque spring motor is a prestressed strip of spring material which is formed into a coil and stored on a small storage drum. 

The free end is then fastened to and backward wound onto a larger output drum. This is the “winding” portion of the spring’s cycle. When the output drum is released, the spring will return to the storage drum to assume its natural curvature thus rotating the output drum and providing virtually constant torque.

The torque of a Neg’ator spring motor is dependent on many factors including material width and thickness, the natural radius of curvature and the diameters of the drums. These motors, due to their high operating stress, provide many advantages in motor size and life cycle at a given load. 

Optimal applications would require fatigue life between 2,500 and 3,500 cycles. 

The constant torque output and long deflection capability of the Neg’ator power package provides a practical and economical alternative to electric motors, dead weights and power springs. This spring can provide up to 100 turns with little effect on torque output. 

Special Features – Neg’ator Spring Motors
- Long deflections at nearly constant torque. Positive or limited negative gradients can be achieved.
- Little intercoil friction and resultant hysteresis as is common in power springs.
- Permits high working stresses due to residual stress resulting in very high energy storage.
- Provides rotary motion directly from output drum or linear displacement via cable and spool arrangement.
- Light duty escapements and governers can be used. 

Hunter Spring’s experienced engineers can help you in designing a motor to meet your size, load and life cycle requirements. Our engineers can also suggest mounting arrangements and stopping devices which can help optimize the performance of your overall product design.

Request more information to see how we can help you with a Neg’ator constant force spring motor solution.