Service Life Of Motor Research Articles

Present Situation and Future Prospects of Motor Cooling System

Background: The motor cooling system is mainly used in aerospace, automotive, and marine fields, where the motor system is cooled to extend the service life and safety of the motor. The running power of motors rises too fast, which leads to the failure of heat dissipation as expected and shortens the service life of motors. Therefore, it is necessary to choose an appropriate cooling mode for motors to improve their cooling structure, reduce their temperature rise, and improve their reliability and service life. The internal motor cooling system can perform fixed-point heat dissipation, but the overall heat dissipation is poor. The external motor cooling system can perform overall heat dissipation but has high requirements on the structure. Over the years, the application and development of motor cooling systems have gained more and more attention. Objective: This paper discusses the structural characteristics, advantages, and development trends of the motor cooling system in order to reduce the temperature rise of the motor and improve its reliability and service life. This paper aims to provide an overview and systematic guidance for future designs of the motor cooling system. Methods: According to the structural characteristics of the motor cooling system and the requirements of the motor application field, the most typical internal cooling system and external cooling system in the motor cooling system are summarized. Results: By analyzing the causes and hazards of motor heating, the limited requirements of the motor system in use are summarized. The motor system is classified and compared based on the structure, heat dissipation principle, and use of the motor heat dissipation system. The characteristics of small volume and strong heat dissipation ability are also summarized. Based on the analysis of the internal and external cooling system, the problems of complex structure and poor cooling effect are summarized, and the future development trend and direction of the motor cooling system are discussed in detail. Conclusion: This paper divides the motor cooling system into an internal cooling system and an external cooling system according to the specifications and operating environment. This paper expounds on internal and external cooling systems' different principles, advantages, and disadvantages. This paper summarizes the cooling systems in recent years in order to facilitate their subsequent development and use. The main components of additional patents for future inventions are motor cooling systems, innovation in structure simplification, and cost performance optimization.

Experimental research of variable rotation speed ICE-based electric power station

Developing variable rotation speed ICE-based stand-alone electric power stations which can supply distant regions and autonomous objects with electricity are of scientific interest due to the insufficient study. The relevance of developing such electric power stations is determined by their usage is to provide a significant fuel saving as well as increase ICE motor service life. The article describes the electric station of autonomous objects with improved fuel economy. The article describes multivariate characteristic. Multivariate characteristic shows the optimal frequency of rotation of the internal combustion engine. At this rotational speed there is the greatest fuel economy.

A Novel SVPWM Algorithm for Five-Level Active Neutral-Point-Clamped Converter

The five-level active neutral-point-clamped (5L-ANPC) converter is becoming an attractive topology of multilevel converter family. A novel SVPWM algorithm based on line voltage coordinate was studied in this paper to overcome shortcomings of the traditional algorithm. Through coordinate transformation, steps of determining the basic vectors and the solution about the basic vector corresponding action time are simplified. Combining with the characteristics of 5L-ANPC converter and the new control algorithm, a method of controlling the voltage balancing of dc-link capacitors and floating-capacitors is proposed. According to the voltage of dc-link capacitors, the suitable switching sequence which can balance the voltage of dc-link capacitors is chosen. The high common-mode voltage will affect the service life of motor and reduce the reliability of the system especially in high-voltage converter. The common-mode voltage is also reduced by choosing the right switching state in this paper. The validity of the proposed method was proved by the experimental results.

Effect of Cumulative Damage on Rocket Motor Service Life

ABSTRACTTwo series of antihail rocket propellant grains failed only 3 months after production, due to the appearance of cracks in the grain channel. Structural integrity analysis demonstrated sufficient reliability at the beginning of service life. Further analysis showed that under temperature loads, cumulative damage during the short period in field stocks caused the grain failure, despite the established opinion that such failure can become significant only after lengthy storage. A linear cumulative damage law is evaluated by exposing a number of hydroxyl-terminated polybutadiene (HTPB) composite propellant specimens to different but constant stress levels. The analysis showed that cumulative damage must not be overlooked at the design stage. Further, a positive correlation between the propellant cumulative damage law and tensile strength is strongly indicated.

Radiation-Resistant Valve-Inductor-Type Motor as a Part of Technological Installation for Recycling Nuclear Industrial Waste

Induction motors with conventional organic insulation are used at technological plants designed for recycling nuclear fuel waste of nuclear power stations. In the nuclear radiation environment, the service life of these asynchronous motors does not typically exceed 3-4 months as the winding insulation is destructed being exposed to nuclear radiation. This results in costs increase. To prolong the motor service life and reduce the costs, a valve-inductor-type motor is being developed for this application field due to a simple construction of the stator windings and the feasibility of using non-organic insulation.

Assessment scheme for the chemical compatibility of materials with cast double base propellants

AbstractThe scheme for the compatibility assessment of materials with cast double base propellants as operated at Royal Ordnance Summerfield is described. Central to the scheme is the recognition that evaluation of the compatibility of materials must consider two areas of safety. These are on‐site process safety requirements, and rocket motor service life which includes safe chemicalstability and the long term functioning and reliability of a store. To rationalize testing, a system of compatibility testing to defined categories classified by the application and usage of a material is followed.

Rocket motor service life calculations based on the first-passage method

Covers advancements in spacecraft and tactical and strategic missile systems, including subsystem design and application, mission design and analysis, materials and structures, developments in space sciences, space processing and manufacturing, space operations, and applications of space technologies to other fields.