如具有特殊环境防护能力的电机，还须在电机系列规格号的后面加特珠环境代号，例YB160M, -2W，w表示户外用。表5- 11为电机的特殊环境代号。
根据GB 50058《爆炸和火灾危险环境电力装置设计规范》标准，把爆炸和火灾危险环境分为爆炸性气体环境、爆炸性粉尘环境和火灾环境三种。表5- 12为爆炸与火灾危险环境和分区的一般定义。爆炸性气体环境用电气设备种类，I 类为煤矿用电气设备，II类为除煤矿外其他爆炸性气体环境用电气设备。用于煤矿的电气设备其爆炸性气体环境除甲烷外，可能还有其他爆炸性气体时，应按I类和II类的相应气体要求进行规定制造与检验，I类性能低于II类，因此不能对等的用于工厂，所有防爆型式的II类电气设备，其允许的最高表面温度分为T1~T6六组，如表5-13所示。防爆电气设备除符合通用要求外，还须分别符合各防爆型式的专用标准。
根据爆炸危险区域的分区，电气设备的种类和防爆结构的要求，应选择相应的电气设备，电机的防爆结构型式选择见表5-15。选用的防爆电气设备的级别和组别，不应低于该爆炸性气体环境内爆炸性气体混合物的级别和组别。当存在有两种以上易燃性物质形成的爆炸性气体混合物时，应按危险程度较高的级别和组别选用防爆电气设备。对爆炸性气体选择电机的组别和温度组别见表5 - 16。渣浆泵
Classification of protection grade of motor shell of slurry pump
According to GB 4208 standard, the enclosure protection level code is composed of characteristic number IP and protection characteristic number (2). See table 5-9 and table 5-10 for protection characteristic figures.
Sometimes, when it is necessary to express some additional meaning, s or m, W are added after the characteristic number to mark between IP and the characteristic number.
S-the test to prevent water from entering into the interior to reach harmful degree is conducted when the equipment is not in operation (static).
M-tests to prevent water from entering the interior to a harmful degree are carried out with the equipment running.
W -- used under specified climatic conditions and with additional protective measures or methods.
If there is no supplementary letter, it means that this protection level is applicable under all normal use conditions. If only one characteristic number is needed to indicate the degree of protection, the ignored number must be replaced by the letter X, such as IPx4.
The protection level of D, e and N explosion-proof motors shall not be lower than IP54.
(2) protection type of special environment
For motors with special environmental protection capacity, the special environment code shall be added after the motor series specification number, for example, yb160m, - 2W, w indicates outdoor use. Table 5-11 shows the special environment code of the motor.
8. Motors for explosive and fire hazardous environments
(1) division of explosion and fire hazard environment and classification of explosion-proof equipment
According to GB 50058 code for design of electric power installations in explosive and fire hazard environment, the explosive and fire hazard environment is divided into explosive gas environment, explosive dust environment and fire environment. Table 5-12 gives the general definition of explosion and fire hazard environment and zone. Types of electrical equipment for explosive gas environment: class I electrical equipment for coal mine, class II electrical equipment for explosive gas environment other than coal mine. In addition to methane, the explosive gas environment of electrical equipment used in coal mines may have other explosive gases, which shall be manufactured and inspected according to the corresponding gas requirements of class I and class II. The performance of class I is lower than that of class II, so it cannot be used in factories equally. For all explosion-proof type of class II electrical equipment, the maximum allowable surface temperature is divided into six groups T1 ~ T6, as shown in table 5-13. In addition to meeting the general requirements, explosion-proof electrical equipment shall also meet the special standards of each explosion-proof type.
Class I I flameproof (d) and intrinsically safe "I" electrical equipment are divided into class IIa, IIb and IIC. The equipment marked IIB can be used for the service conditions of IIA equipment, and the equipment marked iic can be used for the service conditions of IIA and IIB equipment.
Examples of explosion-proof signs are shown in table 5-14.
(2) motor selection in explosive gas environment
Corresponding electrical equipment shall be selected according to the division of explosion hazardous area, type of electrical equipment and requirements of explosion-proof structure. See table 5-15 for the selection of explosion-proof structure type of motor. The grade and group of the selected explosion-proof electrical equipment shall not be lower than that of the explosive gas mixture in the explosive gas environment. When there is an explosive gas mixture formed by more than two inflammable substances, the explosion-proof electrical equipment shall be selected according to the higher level and group of danger. See table 5-16 for explosive gas selection motor group and temperature group. Slurry pump