Pay attention to the temperature rise limit of exp

2022-09-23
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Pay attention to the temperature rise limit of explosion-proof electrical equipment

if the various conditions of explosion-proof electrical equipment affecting the given temperature rise are not appropriate, it may cause danger. Therefore, when selecting equipment for green products, we must carefully study these conditions. 1. Load conditions (1) working mode and rating the rating of electrical equipment must be suitable for the load value under the working mode of the equipment. The relationship between the formula and the rated value of the working party in recent years is as follows: A. continuous working mode, continuous rated value should be adopted; B. Short time rating shall be adopted for short-time working mode; C. Intermittent working mode and repeated working mode should adopt the concept of "code" related to the heating and cooling state of electrical equipment in corresponding operation: original code, inverse code, complement code, ASC Ⅱ gray code, continuous rating of approximate temperature change, short-time rating and repeated rating. (2) Working characteristics electrical equipment must select appropriate working characteristics according to the conditions of use. A. When the electrical equipment starts, stops or rotates repeatedly, it is necessary to study the inertia moment of the specified load, braking type and braking time, as well as the load duration and frequency. B. When speed control is required, the speed control range and load characteristics (constant torque or power, etc.) shall be specified. The working methods mentioned above are explained as follows: working time refers to the use state of electrical equipment during load time. Continuous working mode actually refers to the continuous operation after the temperature rise reaches the specified value under a certain load. The short-term working mode refers to that under a certain load, when the temperature rise of the electrical equipment has not reached the maximum specified value, it should stop running after the specified time, and then start up when the equipment temperature has fallen to the same as the ambient temperature. Intermittent working mode refers to that under a certain load, the electrical equipment stops after running for a certain period of time when the temperature rise reaches the maximum specified value. When it does not fall to the same as the ambient temperature, it can run under the same load again, and then work repeatedly at irregular intervals. The repeated working mode refers to that the operation period and the shutdown period are regarded as a cycle, which is the repeated working mode. 2. Cooling mode and its protection device electrical equipment can easily cause environmental pollution during the operation of the cold waste plastic granulator, but achieve the purpose of reducing temperature, so the cooling mode and cooling conditions should be determined. Cooling methods of electrical equipment are generally divided into self cooling type and other cooling type. Self cooling depends on the conditions of the electrical equipment itself to emit the heat generated by itself. Some equipment is equipped with heat sinks on the surface of the shell, through which the heat is dissipated; Some add a cooling fan on the rotating shaft to take away the heat through the fan

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