Gear pump special oil pump motor temperature rise test has a doorway, Dalan motor takes you to explore!

In the previous issues, Dalan Motor Xiaobian talked with everyone about the temperature rise or temperature of the motor. However, the seemingly simple problem of temperature rise or temperature of the motor is too esoteric. It is difficult to say how much. Said thoroughly. Let's take a look at the heat of temperature and temperature rise, and let's talk about the temperature rise or temperature test of the special oil pump motor of the gear pump.

In fact, the test of the temperature rise or temperature of the motor is also a big problem. It is roughly divided. The test methods of the motor temperature include the resistance method, the thermometer method, and the thermal element method. What methods should be adopted according to the actual needs, combined with a large amount of data accumulation, infiltrate some empirical methods, and strive to minimize the deviation between the measured value and the actual value.

Thermometer method:

The thermometer method measurement reflects the local surface temperature of the winding insulation. Many motor manufacturers have placed thermometers in the position of the rings during the type test. The measurement tests represent the temperature of the stator core of the motor. This number is on average about 15 °C lower than the actual maximum temperature of the winding insulation, the "hottest spot".

Resistance method:

The resistance method measurement reflects the average value of the magnet wire temperature of the entire winding. This number is 5 to 15 °C lower than the actual maximum temperature by different insulation levels. The principle of the method is to measure the cold and hot resistance of the conductor and calculate the average temperature rise of the winding according to the relevant formula. It is especially emphasized that this temperature rise is only the average temperature rise and does not represent the temperature rise of each point of the winding, but from the theoretical analysis point of view, the value measured by this method is relatively accurate.

Thermal element test method:

This method is to embed thermal elements such as copper, platinum resistance thermometers or thermocouples in windings, cores or other parts that need to measure the highest temperature. The measurement results reflect the temperature at which the temperature measuring element contacts. Large motors often use this method to monitor the operating temperature of the motor.

The temperature rises above the rating plate under rated load. No matter what the situation is, the motor is faulty, and it must be stopped for inspection, especially when the temperature rise suddenly becomes larger.

Possible reasons include:

(1) External cause: the grid voltage is too low or the line voltage drop is too large (more than 10%), the load is too heavy (more than 10%), the motor and machinery are not properly matched;

(2) Internal causes: single-phase operation of the motor (ie, the phase loss we often say), short-circuit between turns, phase-to-phase short circuit, grounding of the stator, damage to the fan or untightening, blockage of the air duct, damage to the bearing, friction between the stator and the rotor, motor and Cable joints are heated (especially copper-aluminum or aluminum-aluminum connections), and the motor is corroded or damp.

(3) Others: In theory, the motor can be reversed, but some motors have directionality (especially 2P motors). If it is reversed, the temperature rise will exceed many; this problem often occurs during the motor repair process.



----- Editor-in-Chief: Dalan Oil Pump Motor 02-Procurement Consultant

Copyright http: / (Dalan Motor) Reprint, please indicate the source
Http://news.chinawj.com.cn