Introduction to NEMA standard motors and explosion-proof standards
NEMA standard motor
NEMA standard motors are mainly used in the United States, Canada, and Mexico. The operating frequency of the motor is 60HZ and the operating voltage is 230/460V. The corresponding synchronous motor speeds are: 3600RPM for 2-pole motors, 1800RPM for 4-pole motors, and 1200RPM for 6-pole motors. The main brands of NEMA standard motors are: Baldor Motor, Reliance Ryan Motor, Emerson US Emerson US Motor, Marathon Motor.
Definition of NEMA standard motor protection level
Enclosure(NEMA) | Corresponding IP#(IEC) | Definition |
ODP | Reach IP22 | Prevent fingers from touching or approaching live or rotating parts in the shell. It can prevent solid foreign objects with a diameter greater than 12mm from entering the shell, and dripping water within a 15-degree angle to the vertical should have no harmful effects |
WPⅠ | Reach IP23 | Prevent fingers from touching or approaching live or rotating parts in the shell. It can prevent solid foreign objects with a diameter greater than 12mm from entering the shell, and water spraying within a 60-degree angle with the vertical line should have no harmful effects |
WPⅡ | Reach IP24 | Prevent fingers from touching or approaching live or rotating parts in the shell. It can prevent solid foreign objects with a diameter greater than 12MM from entering the shell, and there should be no harmful effects when subjected to splashing water in any direction |
TEFC | Reach IP54 | Completely prevent fingers from touching or approaching live or rotating parts in the shell. Prevent harmful dust deposits. The dust cannot be completely prevented from entering the motor housing, but the amount of dust entering will not affect the normal use of the motor. Withstand splashing water from any direction should have no harmful effects |
XP(Explosion proof) | Reach IP54 | Completely prevent fingers from touching or approaching live or rotating parts in the shell. Prevent harmful dust deposits. The dust cannot be completely prevented from entering the motor housing, but the amount of dust entering will not affect the normal use of the motor. Withstand splashing water from any direction should have no harmful effects |
WASHDOWN(Water flush) | IP55 | Completely prevent fingers from touching or approaching live or rotating parts in the shell. Prevent harmful dust deposits. The dust cannot be completely prevented from entering the motor housing, but the amount of dust entering will not affect the normal use of the motor. Withstand water spray from any direction should have no harmful effects |
NEMA standard motor explosion-proof grade definition
Hazardous location: An area where an explosion or fire may occur due to flammable gas, steam, dust, light source or suspended matter.
DIVISION 1 (Zone 1): DIVISION 1 (Zone 1) is a general situation, and the hazards may appear in daily production or frequent repairs and maintenance.
DIVISION2 (Zone 2); DIVISION 2 (Zone 2) is an occasion where hazards occur under abnormal conditions. Hazardous substances are confined in closed containers or closed systems. The hazard only occurs in the event of an accidental impact, collision or unusual misoperation.
CLASS Ⅰ (Class Ⅰ): The area where the combustible gas or steam in the air reaches a certain amount, and explosion or fire occurs.
CLASS Ⅱ (Class Ⅱ): Places that are hazardous due to combustible dust
CLASS Ⅱ (Class Ⅲ): occasions with flammable light sources or suspended solids
GROUPS | The gas and steam in CLASS Ⅰ (Class Ⅰ) places are divided into four groups A, B, C, and D. These substances are classified according to combustion temperature, explosion pressure and other combustion characteristics | GROUP A | Acetylene |
GROUP B | Hydrogen | ||
GROUP C | Acetic acid, ethylene, recycled propane | ||
GROUP D | Gasoline, ethane, benzene, butane, propane, alcohol, paint solvent, steam, natural gas | ||
CLASS Ⅱ (Class Ⅱ) is divided into three groups: E, F and G. These groups are divided according to the burning temperature and conductivity of hazardous substances. | GROUP E | Metal dust | |
GROUP F | Coal dust, coke dust | ||
GROUP G | Flour, starch, grain dust |
Operating temperature code | Maximum temperature range | Temperature code | Note | |
Start | Termination | |||
450 | 842 | T1 | ||
300 | 572 | T2 | ||
280 | 536 | T2A | ||
260 | 500 | T2B | ||
230 | 446 | T2C | ||
215 | 419 | T2D | ||
200 | 392 | T3 | ||
180 | 356 | T3A | ||
165 | 329 | T3B | ||
160 | 320 | T3C | ||
135 | 275 | T4 | ||
120 | 248 | T4A | ||
100 | 212 | T5 | ||
85 | 185 | T6 | ||
Motor surface temperature code definition
Note: explosion-proof DIVISION (zone), CLASS (level), GROUP (group) and temperature code must be specified in the order of explosion-proof motors