JS.JR Series Three-Phase Asynchronous Motors

Introduction

The JS and JR series medium-sized motors are designed to drive various types of machinery, such as ventilators, compressors, water pumps, crushers, ball mills, cutting machine tools, transportation machinery, and other equipment. They can be used as prime movers in coal mines, mechanical industries, power plants, and various industrial enterprises. Upon customer request, they can also be manufactured in a duct ventilation version.

The protective motors should be installed in indoor environments where the altitude does not exceed 1,000 meters, the surrounding air temperature is not higher than +40°C and not lower than 0°C, and the air is clean without acid, alkaline, or corrosive gases. The motors are not suitable for use in explosive gas or dust-laden environments.

If the surrounding air temperature exceeds the specified limits or the air is not clean, duct ventilation must be used. In this case, the cooling air temperature entering both ends of the motor should be between 0°C and +40°C, and the air pressure inside the ducts and the motor must be higher than the surrounding air pressure. In such cases, a blower or dust filter may be installed.

JS series squirrel-cage motors allow for direct-on-line starting at full voltage. If the customer's power grid does not allow direct-on-line starting, reduced-voltage starting can be used, but the starting torque will decrease in square proportion to the starting voltage. JR series motors must have a starting resistor in the rotor circuit before starting, and direct short-circuiting of the rotor windings is not permitted.

Structure

The basic installation type for the motor is horizontal with a foot-mounted base. All models of the motor can be connected to driven machinery via a coupling. The motor uses a symmetrical radial ventilation system, where cooling air enters from the intake vents on both side end covers. A portion of the air passes over the stator coil's terminal sections through a fan or fan blades on the motor rotor, while another portion passes through radial ventilation slots in the rotor iron core, then exits through the motor casing's exhaust vents.

The duct ventilation motor has the same ventilation system as described above.

The motor uses rolling bearings, with the bearing type listed in Table 1 and the bearing grease type as lithium-based grease ZL-3. From the motor's shaft extension end, the terminal box is located on the right side of the casing. JS series motors can be customized with dual shaft extensions upon customer request. Either shaft extension can be used to transmit the motor's rated power (only a coupling can be used on the ball bearing end).

JR series motors are allowed to run at reduced speed with a lower torque over extended periods. The allowed output power and torque should match the relationship outlined in Table 2 when operating at reduced speed.

If the motor’s load torque (for example, when driving a blower or water pump) and speed decrease in proportion to the square of the speed, the motor is allowed to run at lower speeds for extended periods.

Table 1 - Bearing Specifications

Table 2 - Power, Torque, and Speed Data

Motor Model Naming Convention

• JS115-6: Squirrel-cage asynchronous motor, Frame 11, core length 5, 6 poles.
• JR115-6: Wound rotor asynchronous motor, Frame 11, core length 5, 6 poles.

The JR series motors are available with both brush-lifting and short-circuit devices, as well as without these devices.