HOW TO SELECT AN MBS DYNAMOMETER?

Minimum information required to select a dynamometer:

1. The type(s) of motor(s) to be tested 

2. The power output of the motor

3. Know how the motor(s) mount to a structure 

  • Face mount (i.e., NEMA 56C)

  • Base mount (i.e., 286T, 405T) 

4. What information is required about the motor 

  • Speed vs. torque curve

  • Endurance testing

  • Temperature rise

  • The time at which something fails

Having approximate speed and torque curves would help. Either provide the above information to MBS, who will help you select a system or follow the steps to select a system and provide the information from above and below to MBS when purchasing:

Step 1: Motor Power Output

 

Know the power dissipation. For most applications, the system/brake should be sized to dissipate the power output of the motor under test continuously. If only requiring speed vs. torque curves, the higher 30-second power dissipation curve may be used. Note that a cooling interval of 5 to 10 minutes is required prior to operating the brake at the 30-second power curve again. It is good practice to leave a little room for error which means do not select a system that will use the very limits of the brakes performance.

Step 2: Transmission

Know approximately how much torque the motor provides and at what speeds. Select a pulley ratio so that the brake provides more torque to the motor than the motor may provide. For example, if the motor may provide 1,000 in-oz. of torque, and the brake only provides 550 in-oz. of torque, using a 2:1 ratio (where the brake spins twice as fast as the motor) will convert 550 in-oz. of brake torque to 1,100 in-oz. to the motor. Verify that the maximum brake speed remains below the maximum speed of the motor multiplied by the pulley ratio.

 

If trying to obtain speed vs. torque curve, the stall torque of an MBS dynamometer must be greater than the stall torque of the motor.

Step 3: Load Cell and location

The size and location (i.e., measuring motor torque vs. measuring brake torque) of the load cell(s) may be determined after reading the specification/data sheets of the dynamometers.

Step 4: Transducers (voltage and current) - Optional

Know the type of power and range supplied to the motor under test.