## Most Recent Update

• - A collaboration with Jared. Before any build log, here's a video: That was a Rubik's cube being solved in 0.38 seconds. The time is from the moment the ...
2 months ago

### Electric Motor Data

I built a benchtop electric motor dynamometer.   Here's a collection of data from some electric motors I've used.  This page will be regularly updated as I collect more data.

Have a motor you want characterized?  Get in touch.

Motors Data

Each motor has a PDF summary with some basic data like torque constant, resistance, and test parameters, as well as a few plots.  Here's what these plots are, and how you could possibly use the data.

Efficiency Map
A classic plot in the automotive world.  The efficiency map is $$\frac{torque\cdot speed}{voltage\cdot current}$$, at every torque and speed point.  The efficiency maps are only for 1st quadrant operation: positive torque and positive speed.  Otherwise you get divide by zero problems.  Here's an example of an efficiency map:

The little "islands" in the plot are annoying artefacts of interpolating a surface from scattered data.

Loss Map
The loss map is $$|(torque\cdot speed) - (voltage\cdot current)|$$ at every operating point.  This tells you how much power is dissipated in the motor and controller at a given torque and speed.  Useful for determining how hot your motor is going to get.  Here's an example loss map:

Input Power Map
The input power map is just $$voltage\cdot current$$ at every operating point.  This tells you how much battery or power supply power is required for a given torque and speed.  The red boundary on the plot is the zero-power point.  On one side of the boundary, the motor draws power from the power supply to achieve the torque and speed, and on the other side of the boundary, power is put back into the power supply, i.e. "regenerative braking".  Useful for determining energy requirements for a given task.  Here's an example input power map: