Q&A common to TB-type, PMA-type, and ATM-type measuring instruments

What kinds of motor characteristics do those instruments measure?

Sugawara offers measuring instruments for the following three types of motor load characteristics tests: (1) speed-torque tests; (2) angle-torque tests; and (3) frequency-torque tests. The speed-torque test (1) gradually applies an external load to a test motor rotating under no load to measure motor rotation speed and generated torque at various load levels. For the angle-torque test (2), the test motor secured to the measuring instrument is slowly rotated one full turn. The instrument measures the angle of rotation while the motor turns 360 degrees and the torque generated at each measured angle. The measured torque is sometimes called cogging torque when the motor is deenergized. The torque measured while the motor is in an excitation state is also referred to as torque ripple. The frequency-torque test (3) measures the relationship between the stepper motor drive frequency and torque. It’s also known as pull-in/pull-out torque measurement.

What sensor is used to measure torque?

Torque is generally measured with a strain gauge. In the ATM measurement component used to detect extremely low cogging torque, a sensor with a special shape ensures high-precision measurements. The PC-MMA1 series incorporates an eddy current brake system instead of a strain gauge. This product series is capable of measuring minute speed-torque characteristics by calculating torque from the relative rotation speeds of the motor and magnetic field generator. Sugawara also offers an MEA series that measures motor characteristics by calculating torque based on the moment of inertia inherent to the motor and the motor's angular acceleration, without applying a load to the motor.

Is there a way to measure the characteristics of a motor without a shaft?

In most cases, we can support your measurement with a dedicated jig if you can provide detailed information on the motor shape and other aspects of the motor.