Introduce
YE3P series variable frequency speed regulating low voltage three-phase asynchronous motor
Frame number: H80-450
Capacity: 0.55~1000kW
Number of poles: 2~12P
Voltage: 1000v and below
The specific division standard of dust explosion-proof area
According to the frequency and duration of the explosive dust environment, the explosive dust environment is divided into 3 zones. When selecting a dust-type explosion-proof motor, the suitable motor can be determined according to the site characteristics corresponding to the explosion-proof grade.
Zone 20: An area in which a cloud of combustible dust in the air exists continuously or chronically or frequently for short periods in an explosive environment.
Examples of places that may produce 20 zones:
1, dust container inside the place;
2, storage tank, silo, etc., cyclone dust collector and filter;
3, in addition to the belt and some parts of the chain conveyor dust transfer system;
4, stirrer, grinder, dryer, loading equipment, etc.
Zone 21: A site that, during normal operation, is likely to occasionally exist in an explosive environment in the form of clouds of combustible dust in the air.
In most cases, the zone 21 range can be specified by an evaluation of the release source associated with the environment in which the explosive dust/air mixture is formed.
Examples of places that may produce Zone 21:
1, when there is explosive dust/air mixture inside the dust container, in order to operate and frequently move or open the nearest entry and exit of the dust container outside;
2, when no measures have been taken to prevent the formation of explosive dust/air mixture, in the nearest loading and unloading points, feeding belts, sampling points, truck unloading stations, belt unloading points, etc., outside the dust container;
3, if the dust accumulation and due to the process operation, the dust layer may be disturbed to form an explosive dust/air mixture, the dust container outside the place;
(4) Places inside dust containers where explosive dust clouds may occur (but neither continuously, nor for a long period of time, nor often), such as the interior of the bin with a long cleaning interval (if only occasionally loaded and/or discharged) and the accumulation side of the filter.
Zone 22: Places that are unlikely to exist in explosive environments in the form of airborne flammable dust clouds during normal operation, if only briefly.
Examples of places where 22 zones may be generated:
1, the exhaust port from the dust bag filter vent hole, if once failure, may escape explosive dust/air mixture. Places near the equipment that are rarely opened, or places near the equipment that are prone to leaks due to dust ejections at higher ambient pressure according to experience; Pneumatic equipment, flexible connections may be damaged in the vicinity of such places.
2. Storage bags with lots of powdered products. During operation, the storage bag may fail, causing dust diffusion.
(3) When measures are taken to prevent the formation of explosive dust/air mixtures, places generally classified as zones 21 can be reduced to zones 22. Such measures include exhaust ventilation. Measures should be taken near (dust bag) loading and discharging points, feeding belts, sampling points, truck unloading stations, belt unloading points, etc.
4, the formation of a controlled (clean) dust layer is likely to be disturbed to produce explosive dust/air mixture. Only if the dust layer is removed by cleaning prior to the formation of the hazardous dust/air mixture, it is a non-hazardous site.
Zone 21 is the highest dust explosion-proof grade of the dust explosion-proof motor, which can be used instead of zone 22, and zone 20 is prohibited from entering the electrical appliance.
The difference between B and A in the dust explosion-proof mark: B means that the explosion-proof bonding surface of the motor is A straight port bonding surface, and A means that the explosion-proof bonding surface of the motor is a plane bonding surface, and the two can be interused.
These two dust explosion-proof marks are generally no difference in price, but in the selection of flameproof structural method is different, A21 and B21 have dust environment 21 zone explosion-proof motor use grade requirements.