Products Description

Frequency sensitive rheostat is a contactless electromagnetic starting element specially designed for wound rotor asynchronous motors. Leveraging the property that core eddy current loss varies with current frequency, it enables automatic and smooth impedance adjustment during motor startup. The product boasts a robust structure and requires no complex multi-stage switching mechanisms. It automatically limits current and boosts starting torque at the initial stage of motor startup. As the rotating speed rises, its impedance gradually decreases to deliver smooth stepless starting. Widely compatible with a full range of industrial heavy-duty transmission equipment, it greatly simplifies motor startup control procedures.

Product Advantages

Smooth Starting Throughout the Whole Process

No current surges occur during motor startup, and torque output remains stable and continuous throughout the starting cycle.

Contact-Free Design for Higher Reliability

Common failures such as contact erosion and jamming will not emerge during operation.

Simple and Durable Construction

The product features strong vibration resistance and thermal shock resistance, suitable for harsh industrial operating conditions.

Low Maintenance Requirements

Frequent disassembly and inspection are unnecessary in daily service, substantially cutting long-term operation and maintenance costs.

Notes

Do not leave Frequency sensitive rheostat connected to the rotor circuit for long-term continuous operation. Otherwise, motor operational losses will rise significantly and lead to overheating.

Never arbitrarily alter the iron core air gap or winding wiring configuration. Doing so will damage the preset resistance variation characteristics and impair motor startup performance.

If abnormal casing overheating, unusual noise or other faults are observed during operation, shut down the equipment and cut off power immediately for inspection. Resume operation only after troubleshooting.

Application Scope

Hoisting and Transportation Equipment

Suitable for starting wound rotor motors of overhead cranes, travelling cranes and tower cranes, meeting operating requirements of frequent start-stop cycles.

Mining Equipment

Used for motor startup of heavy mining equipment such as hoists and crushers, adapting to underground working conditions with high impact loads and heavy dust.

Metallurgical Industry

Matched with drive motors for rolling mills and blast furnace charging equipment, ensuring shock-free and smooth motor startup under heavy-load conditions.

General Industrial Transmission

Frequency sensitive rheostat can be applied to wound rotor motors of conventional industrial equipment including fans, water pumps and compressors to realize soft starting.

Relevant Data

Model	Size
	L	B	H	A	A1
BP1-004	245	225	235	150	125
BP1-006	245	251	235	150	151
BP1-008	245	277	235	150	177
BP1-010	245	303	235	150	203
BP1-012	245	329	235	150	229
BP1-204	300	192	220	250	92
BP1-205	300	207	220	250	107
BP1-206	300	222	220	250	122
BP1-208	300	252	220	250	152
BP1-210	300	282	220	250	182
BP1-212	300	312	220	250	212
BP1-305	480	232	400	400	132
BP1-306	480	247	400	400	147
BP1-308	480	277	400	400	177

Maintenance Methods

01/

Periodically check the tightness of all wiring terminals to avoid poor contact caused by loose connections from long-term vibration.

02/

Regularly clean dust accumulated on the enclosure and heat sinks to keep heat dissipation passages unobstructed and maintain optimal heat dissipation performance.

03/

Periodically power off the unit to test insulation resistance between windings and ground. Carry out drying and insulation reinforcement promptly if insulation performance degrades.

04/

Regularly examine the tightness of iron core laminations to prevent lamination loosening after prolonged operation, which may cause abnormal electromagnetic noise and overheating.

FAQ

Q: Can Frequency sensitive rheostat directly replace old-style starting resistance boxes?

A: It can work with most existing control circuits. Replacement can be completed without major modifications to the original circuit.

Q: How can we resolve insufficient starting torque issues of Frequency sensitive rheostat?

A: Performance can be optimized by adjusting winding taps and modifying iron core air gaps to improve the starting torque characteristics of the motor.