Explosion-proof motor explosion-proof principle and inspection methods

Explosion-proof motor Explosion-proof principle and detection methods. The explosion-proof principle of explosion-proof motors is that they can withstand internal explosion pressure without deformation or damage. Using the gap cutting principle, when an explosion occurs inside the motor, firstly, the motor casing has sufficient strength, and during the internal explosion, it prevents flames and explosion products from spreading outwards through the gaps in the casing, preventing external explosive mixtures from igniting. When the fire passes through the gaps of all joints of the motor casing, the joints cool the flame, reducing the flame propagation speed. So let's learn about the explosion-proof principle and inspection methods of explosion-proof motors!

Explosion-proof motor inspection methods:

1. Baseline pressure measurement

Explosion-proof motor The measurement of baseline pressure is used to determine the maximum explosion pressure inside the explosion-proof servo motor during an explosion. An overvoltage test is conducted at 1.5 times the baseline pressure to evaluate the strength of the motor casing. The reference pressure is a value higher than the smooth pressure higher than the atmospheric pressure obtained from the experiment. During the test, the explosion-proof servo motor is placed in an explosion-proof chamber, the inside of the explosion-proof servo motor is filled with an explosive gas mixture, and the internal mixture is ignited using a spark plug installed on the motor casing. The internal explosion pressure is measured using a pressure sensor installed on the casing. A pressure sensor is installed on the front and rear covers of the explosion-proof servo motor, and three tests are conducted. The largest value is used as the reference pressure. Tests are conducted separately under stationary and rotating conditions, and both ends of the cover are ignited separately. At least four sets of motor tests are conducted, and pressure overlap usually occurs during the test. In this case, five tests are required for the corresponding gas. In Class B, to measure the explosion pressure, at least five experiments need to be repeated in a mixture of (241) hydrogen/methane (85/15).

2. Exam data analysis

If one side of the motor end cap catches fire, a certain degree of pressure overlap will occur during the internal explosion. That is, this is because the internal cavity of the motor is separated into two cavities by the rotor, and these two cavities are stable and connected through the air gap between the rotors. The explosion pressure on the non-ignition side is much greater than the explosion pressure on the ignition side. For example, the explosion pressure on the non-ignition side of the EX motor is 5 times the explosion pressure on the ignition side. Therefore, the phenomenon of pressure overlap occurs during the explosion. Ignition at the extended end of the shaft generally results in a higher measured explosion pressure than ignition at the fan end. Due to the complex internal cavity structure of the motor, the explosion pressure of the explosion-proof servo motor in the rotating state is generally greater than that in the stationary state, and there is uncertainty in the test results. The measurement of the motor reference pressure needs to be measured by igniting both end caps separately in the stationary and rotating states. In this way, but there is also a stationary explosion pressure greater than the rotating state. The flame propagation and shock wave propagation generated after ignition at different positions are very complex, and the explosion pressure inside the motor can be reliably measured.

3. Static pressure test

After the standard measurement baseline pressure of the explosion-proof motor, an overvoltage test is conducted at 1.5 times the baseline pressure to evaluate the strength of the explosion-proof servo motor casing. The static pressure test is a commonly used test method by manufacturers. The static pressure test (usually called a hydrostatic test) is also a routine test conducted during the manufacturing process of explosion-proof motors. There are two test methods: dynamic pressure test and static pressure test. The dynamic pressure test is a test method generally used by testing institutions. The test pressure reaches the reference pressure.

The above is an introduction to Explosion-proof motor the explosion-proof principle and inspection methods. If you want to learn more, please feel free to contact us!