Study On Rapid Detecting Methods For AC Traction Motor Windings Insulation Status Of Urban Rail Vehicle

With the development of China’s economic construction and accelerating of urbanization,more and more people come into the cities.Meanwhile,a large number of urban population bringing the increasing pressure to the urban transportation.For easing the pressure,urban mass transit provides a good solution.In order to ensure the safety of urban rail vehicles,vehicle inspection and maintenance should be carried out to ensure the rail vehicle to work in the normal state.As a key component of urban rail vehicles,the performance of AC traction motor directly affects the safety of the urban rail vehicles.Due to the harsh working environment,it’s difficult to guarantee the windings insulation state,thus windings insulation of AC traction motor are often prone to failure.In order to adapt to the requirements for AC motor windings rapid test of urban rail vehicle, on the basic of analynizing AC traction motor windings fault types,characterization and mechanism of fault phenomena, this paper presents a portable device to detect the state of the windings insulation without detaching the traction motor from the bogie.By using 110 V DC battery of the rail vehicle as the power supply system, the device can do the AC high-voltage test,DC high-voltage test and turn-to-turn high-voltage test rapidly.Thus achieved evaluating the full insulation performance of AC traction motor windings.Considering the shortcoming of the traditional turn-to-turn high voltage test for the AC traction motor windings,such as excessive test equipment,unportability,Because when the windings insulation state get deteriorated,the equivalent inductance of the windings decrease, in order to achieve detecting the insulation state of motor winding with the urban rail vehicle, this paper proposes a test method. This method is to load the high-voltage pulse to the motor windings,then measure the rising time of internal windings current,because of the different windings inductance between the fault windings and non-fault windings can cause the diffierences about the rising time,by the contrast of two different rising times to detect the defective windings.