The TPM from alpha gear drives Inc. is a geared motor containing a rotary actuator based on an AC servo motor and high precision planetary gearing. The rotary actuator is characterized by a high dynamic response. With an overall length of 186 mm, the TPM 50 builds up a maximum output torque of 500 Nm at a mass moment of inertia of 2.9 kgcm2. This high dynamic response is due to the 50% reduction in the actuator’s mass moment of inertia, according to the company’s press release. This is because the rotor inertia is reduced by the low-speed motor and mass inertia on the gear side is reduced by about 90% because the gear pinion is directly integrated into the motor shaft, eliminating the need for a clutch.