This chart shows the gearbox output torque vs input speed.

The pink line is the gearbox's rated maximum output torque curve.

The dark blue line is the gearbox's rated continuous output torque curve.

The green lines are the application motion profiles.

The blue dot is the application nominal output torque. It is also sometimes refered to as the RMC (root-mean-cubed) output torque.

Key performance values and margins are displayed in the top right panel.

Tip:
As is the case for all ServoSoft charts, use the chart crosshairs to get chart values, zoom in and pan to focus on a particular area of the chart, and export the chart data to file for further analysis in a spreadsheet or other tools.

ServoSoft calculations are based on gearboxes with efficency that varies with speed.

This is important since most other sizing tools base their calculations on a single efficiency value, which is normally based on the ideal operating point of the gearbox.

As shown in this chart, the efficiency can vary from 84.5% to 90%. Using an efficiency value of 90% throughout the speed range yields a 6.5% error at low and high speeds.

The motor torque chart clearly demonstrates the effect of a gearbox effiency that changes with speed.

In the previous chart above, the gearbox efficiency starts at 84.5% at 0 rpm, then peaks at 90% at 1500 rpm, and then declines to 85% at 3000 rpm.

One important note is that as speed increases beyond 1500 rpm, the gearbox efficiency decreases, causing the motor torque to rise to maintain the same acceleration. Therefore more torque is needed, requiring more inverter current and power, which then effects the sizing of the the electrical system.