I. Overview of the JS Series Squirrel-Cage Rotor Three-Phase Asynchronous AC Motors

    JS-series medium-duty motors can drive various mechanical loads, such as fans, compressors, pumps, crushers, ball mills, machine tools, conveyors, and other equipment. They serve as prime movers in coal mines, machinery industries, power plants, and diverse industrial and mining enterprises.

    The JS series comprises squirrel-cage rotor three-phase asynchronous motors.

    JS-series motors comply with the Ministry-issued standard JB563-64 technical specifications.

    This series features a protected (guarded) enclosure. Upon user request, they may alternatively be supplied in a pipe-ventilated configuration.

Protected-enclosure motors must be installed at altitudes not exceeding 1,000 m, in indoor environments where ambient air temperature remains between 0 °C and +40 °C, and where air is clean and free of corrosive gases such as acids or alkalis. Motors must not operate in atmospheres containing explosive gases or excessive dust.

When ambient air temperature exceeds the above limits or when air cleanliness is inadequate, pipe ventilation must be adopted. In such cases, cooling air supplied to both ends of the motor shall be maintained at 0 °C to +40 °C, and air pressure inside the ducting and motor interior must exceed that of the surrounding atmosphere; blowers, dust filters, or similar auxiliary equipment shall be installed as required.

    JS-series squirrel-cage motors permit full-voltage direct-on-line starting. If the user’s power supply system does not allow full-voltage direct starting, reduced-voltage starting may be employed—however, starting torque will decrease proportionally to the square of the reduced starting voltage.

II. Brief Structural Description of the JS Series Squirrel-Cage Rotor Three-Phase Asynchronous AC Motors

The standard mounting arrangement is horizontal, with foot-mounted frames. All models are compatible with coupling-driven connection to the driven machinery. A symmetrical radial ventilation system is employed on both sides: cooling air enters via inlet openings on both end shields; part flows across the stator winding end-turns, propelled by rotor-mounted fans or fan blades, while another portion passes through radial ventilation ducts in the rotor core, finally exiting via outlet openings on the frame sides.

    The ventilation system for pipe-ventilated motors is identical to that described above.

    Motors utilize rolling bearings; specific bearing types are listed in Table 1, and lithium-based grease ZL-3 is used for bearing lubrication.

     When viewed from the motor’s shaft extension end, the terminal box is located on the right-hand side of the frame.

    JS-series motors can be manufactured with dual shaft extensions per customer requirement; either shaft extension may transmit the motor’s rated power (though only couplings—not belts or gears—may be used at the ball-bearing end).

If the motor’s load torque (e.g., when driving fans or pumps) decreases in proportion to the square of speed, the motor may operate continuously at reduced speeds.

Table 1                                                        Table 2

III. JS-Series Squirrel-Cage Rotor Three-Phase Asynchronous AC Motor Model Designation

Example:        JS115-6 denotes a squirrel-cage rotor asynchronous motor, Frame Size 11, core length code 5, 6-pole.

IV. JS-Series Squirrel-Cage Rotor Three-Phase Asynchronous AC Motor Mounting Dimensions Diagram