Which type of motor protector should I choose?

There are no uniform standards for motor protectors sold on the market, and the model specifications are varied. But which one is the most suitable? How to choose? Dalan Motor reminds you that you should fully consider the actual needs of motor protection when selecting the model, and reasonably choose the protection function and protection method to achieve good protection effect, to improve equipment operation reliability, reduce unplanned parking, and reduce accident losses. The basic selection methods are as follows: 1. Conditions related to selection 1 Motor parameters: First understand the specifications, functional characteristics, protection type, rated voltage, rated current, rated power, power frequency, and insulation level of the motor. 2 Environmental conditions: mainly refers to normal temperature, high temperature, high cold, corrosion degree, vibration, sand, altitude, electromagnetic pollution, etc. 3 Motor use: mainly refers to the characteristics of the mechanical equipment required to drag, such as fans, pumps, air compressors, lathes, oil field pumping units and other mechanical properties of different loads. 4 control mode: control mode has manual, automatic, local control, remote control, stand-alone operation, centralized control of production lines, etc. Start-up methods include direct, step-down, star angle, frequency sensitive varistor, inverter, and soft start. 5 Other aspects: the user's on-site production monitoring management, the severity of the impact of abnormal shutdown on production. 6 There are many factors related to the selection of the protector, such as the installation location, power supply situation, power distribution system, etc.; also consider whether to protect the newly purchased motor configuration, or upgrade the motor protection, or improve the accident motor protection. Etc.; also consider the difficulty of changing the motor protection mode and the degree of impact on production; the selection and adjustment of the protector should be considered comprehensively according to the actual working conditions on site. 2, the common type of motor protector 1 thermal relay: ordinary small-capacity AC motor, working conditions are good, there is no frequent start-up and other harsh conditions; due to poor accuracy, reliability can not be guaranteed, not recommended. 2Electronic type: Detect three-phase current value, set the current value using potentiometer or dial switch, the circuit is generally analog, with anti-time limit or definite time limit. The protection functions include overload, phase loss, stall, etc. The fault type is displayed by an indicator light, and the running power is displayed by a digital tube. 3Intelligent type: Detect three-phase current value, protector uses single-chip microcomputer to realize intelligent comprehensive protection of motor, integrate protection, measurement, communication and display. The setting current is digitally set and operated by the operation panel button. The user can modify various parameters on the spot according to the specific conditions of the motor; the high-voltage motor protection adopts intelligent protection device. 4 Thermal protection type: The thermal element is embedded in the motor, and the protection is good according to the temperature of the motor winding. However, when the motor capacity is large, it needs to be used together with the current monitoring type to avoid the temperature rising sharply when the motor is blocked. The motor winding is damaged due to the hysteresis of the temperature measuring element. 5 Magnetic field temperature detection type: The magnetic field detection coil and the temperature measurement element are embedded in the motor, and are protected according to the change of the internal rotating magnetic field of the motor and the change of temperature. The main functions include overload, stall, phase loss, overheat protection and wear monitoring. The protection function is perfect, and the disadvantage is that the magnetic field detecting coil and the temperature sensor need to be installed inside the motor. 3, the choice of protector type 1 for the working conditions are not high, the operation control is simple, the machine has a small impact on the production of single-machine independent operation of the motor, you can choose the ordinary type of protector, because the ordinary type of protector structure is simple, install the wiring on site Easy to replace, simple to operate, and cost-effective. 2 For the harsh working conditions, high reliability requirements, especially for motors involving automated production lines, should use high-end, full-featured intelligent protectors. 3 For explosion-proof motors, eccentricity due to bearing wear may cause high temperature friction at the explosion-proof gap, which may cause explosion hazard. The wear condition monitoring function should be selected. For special equipment such as large-capacity high-pressure submersible pumps, due to the difficulty in inspection and maintenance, the wear condition monitoring function should also be selected, and the temperature of the bearing should be monitored to avoid major economic losses caused by broom accidents. 4Applicable to protectors with explosion-proof requirements, according to the specific requirements of the application site, select the corresponding explosion-proof protector to avoid safety accidents. ----- Responsible Editor: Dalan Oil Pump Motor 02- Purchasing Consultant Copyright http:/(Dalan Motor) Reprint, please indicate the source http://news.chinawj.com.cn

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