I. Overview

The JR-series medium-duty motors can drive various types of machinery—including fans, compressors, pumps, crushers, ball mills, machine tools, conveyors, and other equipment—and serve as prime movers in coal mines, machinery industries, power plants, and diverse industrial and mining enterprises.

    The JR series comprises wound-rotor three-phase induction motors.

    JR-series motors comply with the Ministry-issued standard JB564-64 technical specifications.

    This series features a protected (guarded) enclosure. Upon user request, motors may alternatively be supplied with pipe-ventilated construction.

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

When ambient air temperature exceeds the above limits or air cleanliness is inadequate, pipe ventilation must be adopted. In such cases, cooling air supplied to both motor ends must be maintained at 0 °C to +40 °C, and internal air pressure within the ducting and motor must exceed ambient pressure; blowers, dust filters, or similar auxiliary equipment shall be added if necessary.

II. Structural Summary

    The standard mounting configuration is horizontal, with foot-mounted frame. All models permit coupling to driven machinery via couplings. Motors employ a symmetrical radial ventilation system: cooling air enters through inlet ports on both end shields; part flows across stator winding end-turns via rotor-mounted fans or fan blades, while another part passes through radial ventilation ducts in the rotor core, finally exiting via side-mounted outlet ports on the frame.

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

    Motors use rolling bearings; applicable bearing designations are listed in Table 1, and lithium-based grease ZL-3 is specified for bearing lubrication.

     Viewed from the drive-end shaft extension, the terminal box is located on the right-hand side of the frame.

    JR-series motors permit continuous operation at reduced speeds under torque-reduced conditions. The permissible output power and torque versus speed relationship must conform to the requirements specified in Table 2.

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

Table 1                                                        Table 2

III. Model Number Interpretation

Example:       

JR115-6 denotes a wound-rotor asynchronous motor, Frame No. 11, core length No. 5, 6-pole.

JR-series motors are available in two configurations: with brush-lifting and short-circuiting devices, or without brush-lifting and short-circuiting devices.

III. Mounting Dimensions Comparison Table