The motor speed regulation of 5 ton bridge crane usually adopts the rotor series speed regulation mode, that is to change the slip speed regulation mode. With the development of frequency control technology, a new breakthrough has been made in the research and development of special frequency converter for lifting equipment, which has been widely used.
1、Design principle of variable frequency speed regulation technology
There are many kinds of frequency converter, and the control mode is mainly low-voltage frequency converter. Due to the advantages and disadvantages of various control methods, when designing variable-frequency speed regulation technology, it is necessary to reasonably determine the system composition function and the capacity of relevant system components according to the specific situation. The commonly used lifting mechanism is generally open-loop control mode. The selection of frequency converter shall meet the following requirements.
(1) The voltage level is consistent with the control motor.
(2) The rated current is 1.1-15 times of the rated current of the control motor.
(3) Select according to the load of controlled equipment.
In addition, it also involves the determination and selection of circuit breaker, contactor, fast fuse, braking resistance and braking unit, overload thermal relay, main circuit cable and control circuit.
(1) When the 5 ton bridge crane is driven by frequency converter, the performance of the whole crane is greatly improved. Such as improving work efficiency, improving power factor, simplifying external wiring, etc., power saving can reach 30% efficiency and reduce cost.
(2) 5 ton bridge crane can realize the functions of stepless speed regulation of motor, smooth and stable traveling of crane, convenient operation, etc., improve the reliability of motor in harsh environment, greatly reduce the damage rate of components and maintenance workload, and greatly improve the maintainability of equipment.
(3) The frequency converter has complete protection functions, such as over-current, overload, over-voltage and other alarm and stop functions, which reduce the failure rate of the crane and improve the safety performance of the equipment. At the same time, the inverter also has the function of limited current. Soft start can reduce the impact on the power grid when the motor starts, which is conducive to the normal operation of other equipment in the power grid.
Overhead Crane Of Dejun Hoist and Crane
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