Life expectancy determination of form-wound coil isolation of high-voltage motor

Jeftenic, Ilija; Stanković, Koviljka; Kartalović, Nenad; Lončar, B.

doi:10.1109/ipmhvc.2016.8012829

Cited by 3 publications

(2 citation statements)

References 8 publications

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“…Variations in the operation temperature result in varying dimensional changes to the windings, insulation, core, and wedging systems. The mechanical stresses on the insulation due to different thermal expansion rates damage the insulation and result in surface damage and microcracking of the insulation [4,5]. This then enables moisture absorption and higher leakage currents [6].…”

Section: Introductionmentioning

confidence: 99%

Employing the Peltier Effect to Control Motor Operating Temperatures

et al. 2023

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Electrical insulation failure is the most common failure mechanism in electrical machines (motors and generators). High temperatures and/or temperature gradients (HTTG) are the main drivers of insulation failure in electrical machines. HTTG combine with and augment other destructive effects from over-voltage, to voltage transients, overload and load variations, poor construction techniques, and thermal cycling. These operating conditions cause insulation damage that leads to electrical insulation failure. The insulation failure process is greatly accelerated by pollutants and moisture absorption. A simple and robust way to reduce HTTG and moisture adsorption is by maintaining constant internal temperatures. The current method to maintain elevated internal temperatures and reduce condensation issues is by internal electrical heating elements. This paper examines the effectiveness of applying thermoelectric coolers (TECs), solid-state heat pumps (Peltier devices), as heaters to raise a motor’s internal temperature by pumping heat into the motor core rather than heating the internal air. TEC technology is relatively new, and the application of TECs to heat a motor’s internal volume has not previously been explored. In this paper, we explore the hypothesis that TECs can pump heat into a motor when out of service, reducing the HTTG by maintaining high winding slot temperatures and eliminating condensation issues. This paper describes a test motor setup with simple resistive heating (traditional method), compared with the application of TECs with heat sinks, heat pipes, and a water circulation heat exchanger, to gauge the capability of TECs to heat the inner core or winding area. In this paper, we demonstrate the full integration of TECs into a motor. The results show that each of the systems incorporating the TECs would effectively pump heat into the core and keep the winding hot, eliminating condensation issues and water ingress due to thermal cycling.

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Section: Introductionmentioning

confidence: 99%

Employing the Peltier Effect to Control Motor Operating Temperatures

et al. 2023

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“…Electrical motors fail for a variety of reasons [1,2] but 40% of motor failures are attributed to electrical insulation failure [3,4]. For motors and generators, a key factor leading to winding electrical insulation failure is insulation aging [5], where abrasion issues and micro-cracking effectively thins the insulation [6]. When combined with moisture absorption, leakage currents quickly lead to failure.…”

Section: Introductionmentioning

confidence: 99%

Research in Life Extension of Electrical Motors by Controlling the Impact of the Environment through Employing Peltier Effect

et al. 2022

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This paper explores the application of thermoelectric cooler/heater (TEC) modules (Peltier heat pumps devices) to control core and winding temperatures, aiming to reduce the effects of thermal cycling and moisture issues that affect the life of electrical machines. Electrical windings in a motor will fail for a variety of reasons, and a major contributor to adverse effects of a motor’s life is humidity. Due to thermal cycling, air containing moisture is drawn into a motor through a variety of access points such as terminal boxes, bearings, end covers and mounting systems. Even spare or replacement motors specially stored in heated spare equipment stores suffer from moisture ingress because of normal daily temperature changes. The better a machine can be kept warm, the less it is affected by moisture and the effects of mechanical stresses from cycling temperatures. A series of experiments were conducted, whereby a TEC was attached to a section of motor core and was set up to pump heat into the core segment. The thermal properties of the core material and the capacity to control winding temperatures along the core in specific locations and over time was measured. The results of this research demonstrate that the temperature of the motor can be tightly controlled, thus enabling the reduction of the effects of moisture, and reducing core and winding temperature differences. This has a positive influence in reducing the thermal stresses, which will result in improved insulation life and machine reliability.

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