Improvement of the Thermal and Mechanical Strength of the Starting Cage of Double-Cage Induction Motors

Abstract

This article discusses the thermal and mechanical exposure of the starting cage of a double-cage induction motor rotor during start-up. Damage to the starting cage is the most common cause of failure of a double-cage winding during long start-ups. It has been indicated that the end region of the double-cage winding is a key area in the search for a more damage-resistant solution. Among the available studies on improving the mechanical strength of double-cage windings, which typically focuses on improving the cooling system, modifying the shape of the slots, or altering the bar material, a new concept of improving the mechanical strength through the modification of the structure of the end region has appeared. This is achieved by applying sleeves onto the ends of the starting cage bars, which helps to reduce the temperature of the connection between the starting bars and the end rings. A simulation of the temperature field of a double-cage induction motor with this new design is performed and discussed in this paper. It has been confirmed that the new design solution effectively improves the mechanical strength of the starting cage, making it less prone to damage caused by thermal stresses.

Machine Health Monitoring and Fault Diagnosis Techniques Review in Industrial Power-Line Network

“…Different authors [23][24][25][26] in recent years have discussed multiple-motor faults detection using MCSA method, but they isolated motors from the system. Author [26] introduced, in a concise manner, MCSA for the diagnosis of abnormal mechanical and electrical conditions that specify, or may cause, a failure of multiple induction motors, but analyse through separation of the system. The MCSA utilises the results of signal analysis of the stator electric current for the detection of broken rotor bars, air-gap eccentricity and other component damage.…”

“…Normally, model-based methods have also been used to collect the dynamic response of systems under normal and fault conditions, by different authors [25][26][27][28], but on motors isolated from systems. A general architecture of the modelbased method is shown in Figure 3 as follows.…”

Starting Pulse Vibration Torque Analysis of Aviation Variable Frequency Asynchronous Motor Based on Low-Frequency Step-Down Starting Methods

“…It is assumed that the constant power load is driven, and the motor starts with load at the same time for meeting k st the design requires k st = 1.2~1.4. Coupled with the (15) and (19), (21) and (25), (27) and (31), respectively. The simulation results are shown in Table 3.…”

“…Therefore, the starting pulse vibration of aviation variable frequency asynchronous motors is very large at a low-frequency (360 Hz) power supply, and the impact on the mechanical system is more serious [19]. It directly affects the reliability, fatigue, and life of mechanical system [20,21]. The higher requirement is proposed for the mechanical system design.…”

Bearing Fault Diagnosis Approach under Data Quality Issues

“…Applying this approach on any system is directly dependent on the real system model and its outputs. In this approach, the dynamic response is collected from the system under faulty and normal operating conditions [8][9][10]. Then, a comparison between the output response parameters and simulated data can help in assessing the condition of the mechanical component.…”