Test Stand and Testing Method for an Asynchronous Electric Motor Equipped with a Sliding Liquid Metal Contact Unit

Determination of the real mechanical characteristics of an asynchronous electric motor with a phase rotor equipped with a liquid metal contact unit is one of the most important parts of research and development work. Considering the significant changes made to the engine design by creating a sliding liquid metal contact unit, it was necessary to develop a specialized test bench. The purpose of the study is to develop a test bench and methodology for conducting braking tests of asynchronous electric motors with a phase rotor equipped with a sliding liquid-metal contact unit. Calculation. The design feature of the stand is the use of a VAZ disc brake as a braking device. The used torque sensor M40 from Tilkom allows for torque control taking into account the requirements of the GOST IEC 60034-2-1-2017 standard with a relative error of no more than 0.2% at an output signal frequency of 5 kHz. A special feature of the testing method is the need to preheat the inner strip of the sliding liquid metal contact unit to a temperature of about 60°C to prevent crystallization of liquid gallium and its intermetallics. Processing of the Results Obtained. The difference in torque values at the rated rotation speed of an asynchronous electric motor with a phase rotor of the 5 MTN112-6ul series, equipped with a sliding liquid-metal contact unit and equipped with a traditional brush mechanism at the rated rotation speed was no more than 3%. The difference in values changed with a change in the phase imbalance of the power supply network. Conclusions. The developed stand and the method of braking tests of the asynchronous electric motor with a phase rotor of the 5 MTN112-6ul series, equipped with a sliding liquid-metal contact unit, made it possible to establish that the value of the torque at the nominal rotation frequency differs from the torque at the same rotation frequency of the base motor by no more than 5%.