Many companies are now increasing their research, development and manufacture of high-efficiency motors to conform to these new mandatory standards and expectations. These development programs demand rigorous testing of multiple parameters to establish that any new designs meet – and possibly exceed – the requirements of the relevant standards.
One of the more important areas of testing is in torque measurement and in many cases there is more than one approach. HBM has a number of different solutions to suit customers’ individual needs.
T20WN torque transducer
For example, HBM’s T20WN torque transducer measures static and dynamic torque and rotation speed or angle for turning or static machine parts. It is designed for measuring small to medium torques, such as are found on performance or function test benches for domestic or business machines. The T20WN has an integrated bearing that allows it to be fitted as a support bearing and simplifies handling as well as featuring electronics with a ±10 V output signal.
T40B digital torque transducer
By contrast the T40B digital torque transducer can measure static and dynamic torque on rotating shafts. In addition, the torque transducer is equipped with a magnetic speed measuring system. Test beds can be extremely compact because of the short construction of the transducer making it suitable for a very wide range of applications.
Chinese regulations require that instrumentation used to measure torque is accurate to ±0.2% of full scale while instrumentation used to measure frequency needs an accuracy of ±0.1% full scale. Speed measurements must be accurate within 0.1% or 1 revolution per minute whichever gives the least error.
With HBM’s T40B series the temperature impact TC 0 and TC span is 0.05%/10K (50Nm = 0.1%/10K) and in most motor test applications there is little temperature change so the focus is more on linearity and repeatability. This means that HBM’s T40B torque transducer can ensure an accuracy of better than 0.2% full scale while taking into account the most important parameters.
In addition the T40B torque transducers are available with different ranges - 5kNm, 1kNm, 200Nm, 50Nm – so that they can easily meet the requirement for torque sensors with accuracy 0.2% full scale for motor tests. This saves costs while the simplified installation makes maintenance much easier.
The T40B features an output pulse count of 1024 pulses/revolution from 50 Nm to 10 kNm, covering all measuring ranges. The magnetic rotational speed measuring system with high output pulse count allows precise measurement of rotational speed, especially at low rotational speeds, to give reliable measured values.