1、 Conditions related to selection
The selection of motor protection involves the reasonable matching relationship between the motor and the protector. The following are several conditions and factors related to protection, providing reference for users when selecting.
01. In terms of motors
The model specifications, motor functional characteristics, protection type, rated voltage, rated current, rated power, power frequency, insulation level, etc. that need to be understood first. These contents can provide users with reference on how to correctly use, maintain, and select protectors.
02. Environmental conditions
Mainly refers to normal temperature, high temperature, high cold, corrosion degree, vibration degree, sandstorm, altitude, electromagnetic pollution, etc.
03. Purpose of Electric Motor
Mainly refers to the characteristics required for dragging mechanical equipment, such as fans, water pumps, air compressors, lathes, oil field pumping units, and other different load mechanical characteristics.
04. In terms of control system
The control modes include manual, automatic, local control, remote control, independent operation of a single machine, and centralized control of the production line. The starting methods include direct, voltage reduction, star delta, frequency sensitive variable resistor, frequency converter, soft start, etc.
05. Other aspects
Are users more casual or rigorous in on-site production monitoring and management, and the severity of the impact of abnormal downtime on production.
There are many factors related to the selection of protectors, such as installation location, power supply situation, and coordination with the distribution system; It is also necessary to consider whether to configure protection for newly purchased motors, upgrade motor protection, or improve protection for accident motors; We also need to consider the difficulty of changing the motor protection method and its impact on production; The selection and adjustment of protectors should be comprehensively considered based on the actual working conditions on site.
2、 Selection of Yinmengda motor under working conditions
1. For single machine independent operation motors that do not require high working conditions, simple operation and control, and have relatively casual monitoring and management, and have little impact on production during shutdown, ordinary type protectors can be used. Due to the simple structure of ordinary type protectors, on-site installation, wiring, replacement, and operation are simple, convenient, and have high cost-effectiveness.
2. For MCC systems that require high working conditions, safety, and continuity, as well as a high degree of automation and the need for dedicated control, monitoring, and management, medium to high end and fully functional protectors should be selected for network monitoring.
3. For explosion-proof motors, eccentricity caused by bearing wear may result in high temperature friction at the explosion-proof gap, posing an explosion hazard. Therefore, the wear status monitoring function should be selected. For large capacity high-pressure submersible pumps, due to the difficulty of inspection and maintenance, wear status monitoring function should also be selected to avoid significant economic losses caused by sweeping accidents.
4. Protective devices used in places with explosion-proof requirements should be selected according to the specific requirements of the application site to avoid safety accidents.
3、 Main functional characteristics of intelligent motor protector
Protection functions: overload protection, phase failure protection, three-phase unbalance protection, locked rotor protection, undervoltage protection, overvoltage protection, leakage protection, ground fault protection, light load protection, no-load protection, short circuit protection.
Control functions: direct start, forward and reverse start, star delta start, direct bypass start, autotransformer step-down start, multi-party start control.
Display monitoring: operating status, three-phase current, line voltage, leakage current, fault information, cumulative working time of the motor, number of faults, and other information.
Setting functions: rated current, protection current curve, starting time, three-phase imbalance, locked rotor ratio, leakage current value, overvoltage and undervoltage value, communication address, self starting time of the motor when the protector is powered on.
Remote transmission function: It has DC4-20mA standard analog output and does not require an external power supply.
Communication function: 256 protectors can form a conventional protection control network with a computer through RS485 serial communication. Remote data setting and display alarm, remote motor start, stop control, etc.
Memory function: It can store the causes of ten recent motor failures, and can press the reset button to retrieve the fault code of the last motor occurrence, and press it again to display the previous one.
