In some working conditions, direct attachment of an SMSR isn't possible or desirable. In these certain situations, the shaft the SMSR is intended to drive is its only support. When an SMSR is mounted directly onto a driven shaft with no other extra support, it must be attached to a torque arm. This is a pivoted link that connects the SMSR to a fixed anchor point. The purpose this arm is to resist the torque developed by the SMSR while it is running, meaning it will prevent the SMSR from counter-rotating on the machine structure during operation.
Torque arms come in many different sizes and can be designed to suit specific applications. The are a very useful accessory and, in some working conditions, essential to have to ensure safety and effective operation of the SMSR.
