Torque

Bushing Mount Potentiometers

Standard torque specifications provide an optimum design for potentiometer life and electrical performance. Increasing the torque from the standard catalog specification may reduce rotational life. Conversely, reducing the torque increases susceptibility to the effects of vibration and shock. In some cases, noise will also increase.

For high torque requirements, it is necessary to specify minimum and maximum running torque. For optimum rotational life, the following torque specifications are typical:

Single-turn	0.5 to 3.0 oz-in
Multi-turn	2.0 to 8.0 oz-in (1.0 oz-in = 0.705 N-cm)

Higher torque is normally achieved by use of a thrust or wavy washer compressed between the rotor block and the front lid. An alternate method of achieving higher torque is by using o-rings and torque grease.

Servo Mount Potentiometers

The majority of requests for custom torque will involve servo-mounted potentiometers and will typically require a very low torque. In these cases, it is best to request technical assistance from the local Field Application Engineer before agreeing to the customer's request.

Resistance Tolerance

Bourns standard precision potentiometers are designed with optimum total resistance (TR) tolerance and linearity performance. Your customer should be advised that adjusting one parameter might affect the other due to the fact that they are interrelated. For example, tightening the TR tolerance makes it difficult to control linearity, and vice versa.

TR tolerances may be tightened to a limit depending on the element type:

Wirewound	±3%
Conductive plastic	±5%

Tighter resistance tolerances may be achieved by use of external shunting resistors in the customer's circuit design.