There are large selections of various springs for brush holders. The advantage of constant force spring for carbon brush are as following: Constant pressure for commutator in any brush length. Increases brush life, reduces electrical wear. Compact design for smaller motor overall diameter that allows longer brushes and larger commutators, featuring reduced spark, lower influence of electromagnetic interference(EMI). The product range from 0.03~0.75mm in thickness and 1~50mm in width.

Constant torque spring is made by winding steel strip into coil. When springs are counter wound on to output drum from its natural type by a load, force to resist uncoiling will be occurred. However, if load disappears, a constant torque will be output from output drum at the same time. Therefore, it is called constant torque spring. Comparing it with traditional power spring, its advantages are following?To exert nearly constant torque during entire stroke. It has better performance than power spring in more revolution designs. All revolutions are almost useful revolutions. It’s high efficiency. The product range from 0.03~0.75mm in thickness and 1~50mm in width.