A summary of motor temperature rise and the temperature rise of the knowledge: Temperature rise is the motor and the environment temperature difference is caused by the electric heating. Run the motor iron core in alternating magnetic field can produce iron loss, winding can produce copper loss, after the power supply and other stray loss, etc. These will make the motor temperature perkins diesel generator rise. On the other hand motor will also heat dissipation. When heating and cooling is equal to equilibrium state, temperature no longer rises and stable on a level. When fever increase or reduce the heat will destroy the balance, make temperature continues to rise, enlarge the temperature, increased heat dissipation, at a higher temperature reaches a new equilibrium. But when the temperature difference of the temperature rise www.facebook.com/dongfeng.motor has increased than before, so that temperature is an important index in motor design and operation, marked the fever of the motor, in operation, such as the motor temperature rise suddenly increases, motor has a fault, or duct obstruction or load is too heavy. Factors such as temperature and temperature relationships: For the normal operation of the motor, in theory, under the rated load its temperature rise should have nothing to do with environment temperature, but the fact is still affected by the factors such as environmental temperature. When the temperature drops, the normal motor temperature rise will decrease slightly.
This is because the winding resistance R, copper consumption reduced. Each drop 1 ℃, R down about 0.4%. To the cold machine, the ambient temperature increase 10 ℃, the ac synchronous motor temperature increased by 1.5 ~ 3 ℃. This is because the winding copper loss increases with temperature rise. So the temperature change of large influence on motor and closed. Every high air humidity 10%, due to the improvement of thermal conductivity, temperature rise can be reduced by 0.07 ~ 0.38 ℃, an average of 0.19 ℃. Elevation in 1 000 m for the standard, every litres of 100 m, the temperature rise of the temperature increase limit value of 1%. The maximum permissible limit working temperature and working temperature: Usually say that the class A limit working temperature is 105 ℃, A level of the highest working temperature is 90 ℃. So, limit working temperature and the maximum allowable working temperature difference? In fact, it is associated with measuring method, different measuring methods, it reflects the values, the meaning is different also. The thermometer method The measurement results reflect the local surface temperature of the winding insulation. This number, on average, than the actual maximum temperature winding insulation lower "the hot spot" of about 15 ℃. The most simple, the most widely used at the scene of the medium and small motor. Resistance method The measurement results reflect the average temperature of the winding wires. The number than the actual maximum temperature according to different insulation level lower 5 ~ 15 ℃. The method is to measure the conductor of the cold and hot resistance, according to the formula to calculate the average temperature rise. Embedment will copper or platinum resistance thermometer thermometer trial or thermocouples embedded in the winding and iron core or other need to measure the expected high temperature parts. The measurement results reflect the temperature of the temperature measuring element contact point. Large motor is often adopted to monitor the operating temperature of the machine. (see electrical engineer) measurement methods to measure the temperature and the actual maximum temperature have certain difference, so the insulation must be "limit working temperature minus the difference between" is "the highest working temperature".
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