Factors Which Can Induce Corona in Elctric Motor

In some special industrial fields, the corona problem of the motor is relatively serious, which should arouse great attention of the manufacturer. High-voltage motors used in industrial applications such as tap water, chemical industry, metallurgy, cement, coal mines, or high-altitude environments are more prone to corona problems than ordinary application fields, that is, such fields or working conditions will induce the motor to generate corona.

Altitude

In a high altitude environment, the air is thin, which will reduce the corona initiation voltage of the motor winding. For high-voltage motors used under normal environmental conditions, the corona voltage is generally 6 kV, that is, motors whose rated voltage is not higher than 6 kV will not cause corona problems, but if it is in a plateau environment, the corona voltage will be lower. At this value, therefore, high altitude is a cause of corona.

Ambient Humidity

When the humidity of the environment in which the motor is used increases, the corona onset voltage also decreases. Therefore, in some environments with high humidity, such as tap water supply, humid environment close to the sea, and some operating environments with water vapor and fog in the environment during production and processing, the corona voltage of this type of motor will also be reduced, so A motor with a relatively high protection level should be selected according to the specific situation to effectively prevent the occurrence of corona problems.

High temperature

Some insulating or anti-corona materials will cause corona problems if the performance of these materials deteriorates due to the increase in temperature, especially when the temperature rise of the winding is too high.

Gap between winding and core slot 

During the production and processing of the high-voltage motor windings, it will be filled with appropriate slot filling rate and necessary materials, such as mica material wrapping, resistance tape wrapping, insulating material in the gap, and VPI vacuum pressure dipping and other measures to maximize the Eliminating the gap between the conductor and the core slot is a necessary and effective measure to reduce the occurrence of corona problems, and it is also the key to control the manufacture of high-voltage motor windings.

Therefore, the purchaser of high-voltage motors should let the motor manufacturer know the actual operating environmental conditions of the motor as much as possible, and the necessary technical measures can reduce or eliminate the impact of the motor corona problem on the quality of the motor.

Xian Tech Full Simo Motor Co., Ltd. is professional electric AC & DC motor manufacturer in China since 1955. Our products power varies from 0.37 kW to 25000 kW with voltage from 220 V to 11000 V. The motors are widely used in steel, power, cement, metallurgy, water conservation, mining, chemical and many other industries. Welcome to contact with us via email: sales@simo.com.cn