Acceleration Torque

WHAT THIS SCREEN ANSWERS

A motor may run a load comfortably at speed but struggle to get it there in time. Acceleration torque is the difference. It comes from rotational inertia and the requested rate of speed change, then sits on top of any steady process torque. This screen makes the transient demand explicit so a motor is not selected from only the running condition.

The key input is reflected inertia at the shaft being evaluated. A wheel, pulley, gearbox, screw, coupling, and payload all contribute, but they do not always contribute at the same shaft. A ratio changes reflected inertia by the square of that ratio. If the inertia was calculated on another shaft, convert it before using this page or move to the gearbox screen first.

MechPlane converts the requested rpm change to angular acceleration from the stated time. It then multiplies by inertia and adds the steady load torque. A shorter acceleration time raises the transient demand directly. That is useful because cycle-time pressure is often the unspoken reason a promising motor choice becomes marginal.

The result assumes a constant ramp, rigid transmission, and a known inertia. It does not capture jerk, backlash, compliance, controller tuning, thermal accumulation, or a real torque-speed curve. Use it to establish a preliminary peak requirement, then compare the drive against its duty envelope and confirm the motion profile with the selected component documentation.