The primary function of MBS dynamometers is to measure the torque as a function of speed; it allows for the output power to be calculated. Our dynamometers have different set-ups and levels of complexity to test a variety of sizes and types of motors/systems. There are three types of motor mountings: Face, Base, and Carriage. The Face and Base mount styles have two standard frame sizes. There is the three (3) inch series for small motors and the five (5) inch series for larger ones. The frame size of the dynamometers is defined in Section 1 of How To Specify a Dynamometer.

Voltage and current transducers are optional items that are used to measure and record the input power to the motor under test. These are simple devices and are not meant for power analysis (i.e., noise, harmonics, power factor). Our dynamometers can measure and record three types of input power to the motors: 

  • DC, 

  • AC (single phase) 

  • 3-phase (3-ph) AC.

DC voltage and current transducers are required to test a DC motor. For a single phase AC motor, AC voltage, and current transducers are required. To test a 3-phase AC motor, 3-phase voltage and current transducers are required. 

There are two types of 3-phase voltage transducers: 

  • 3-wire, 3-phase (to measure line-to-line voltage: L1-L2, L2-L3, L3-L1) 

  • 4-wire, 3-phase (to measure line-to-neutral: L1-N, L2-N, L3-N).

For DC, AC and AC 3-phase motors holes for voltage and current transducers are pre-drilled. The transducers may be purchased with the system or at a later time. Other types of transducers (to measure pressure and flow rate) may be employed by the dynamometer when testing air or hydraulic motors.


The dynamometer structure, which the Unit Under Test (UUT) couples to, is equipped with a safety cover to prevent an operator from injuring his/her fingers with dynamometer's rotating parts. Another safety feature is a hard stop to prevent the load cell from exceeding load limits.


An optional item is the MBS-IR-1, a temperature sensor that monitors the instant temperature of the brake’s drag ring. It prevents the brake from overheating if used in the non-continuous torque region.

In our tandem dynamometers, we also offer thermocouple inputs to measure and record different sections of the UUT’s temperature. The measurements are graphed in the Test Output graph and are available in the Raw Data table.