Protection warning method and system for frequency converter equipped with multiple motors

Abstract

The invention discloses a protection warning method and system for a frequency converter equipped with multiple motors. According to the protection warning method, the current signal among the frequency converter and the motors is detected, an alarm signal is sent out when overcurrent, default phase or three-phase imbalance occur. By adoption of the protection warning method and system, abnormal faults can be found in time, and the fault motors can be effectively determined.

Description

technical field [0001] The invention relates to a protection and alarm system with a frequency converter and multiple motors and its realization method. Background technique [0002] It is more common in industrial equipment to drive multiple motors to run by one frequency converter, such as: woodworking engraving machine, stone cutting machine, etc. When these equipments are running, one of the motors will be overloaded, over-current, lack of phase, and the current will not Balance fault, if the remaining motors are still running normally, the inverter will not alarm, and the faulty motor has overload, overcurrent, phase loss or current imbalance faults but has not been found, which will eventually cause the faulty motor to burn out; if a short circuit fault occurs , The inverter alarms and stops, but the faulty motor cannot be quickly determined, and it takes a long time to detect the fault point. The above situations will affect the production output and product quality, ...

AI Technical Summary

Problems solved by technology

However, the existing motor state identification device adopts a technical solution circuit that is quite complicated, the equipment cost is high, and the detection of the motor running state is not accurate enough.

[0005] If all the motor overload and overheating signals are sent to DCS for inspection and monitoring to issue an alarm, this is easy and convenient, but there are many motors on site, so if they are sent to DCS, the number of DCS control points will increase a lot, and DCS will need to add a lot of cards components, then the DCS system will be correspondingly large, and a lot of cables from the on-site motor to the DCS will be added, so the investment will be even greater

[0006] In an existing frequency converter with multiple motor systems, one of the motor failures causes multiple motors to stop at the site, or the motors burn out due to long-term faulty operation. It is too difficult to troubleshoot the excessive number of motors on site, and it is impossible to quickly determine the problem. The point of failure will seriously affect the product quality or burn the motor, and even bring about more serious personal safety problems; the existing DCS inspection and monitoring and alarm system can solve the above problems, but the cost is very large, and it is difficult for manufacturers based on cost considerations and site constraints. accept this offer

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