The function of the thermal relay is mainly used to carry out overload maintenance on the asynchronous motor, and his operating principle is that after the overload current passes through the thermal element, the bimetal sheet is heated and twisted to advance the action organization to drive the contact action, so as to disconnect the motor control circuit to realize the motor power-off thermal relay parking, and play the role of overload maintenance. In view of the fact that the heat transfer needs to be a long time during the heating and twisting process of the bimetal sheet, therefore, the thermal relay cannot be used for short-circuit maintenance, but can only be used for overload maintenance, and the symbol of the thermal relay is FR.
Because the thermal relay operates when heated, the thermal inertia is large, so even if the current through the heating element exceeds the setting current several times in a short time, the thermal relay will not operate immediately. Only in this way, when the motor starts, the thermal relay will not act due to the large starting current, otherwise the motor will not be able to start. On the other hand, if the current exceeds the setting current by not much, it will operate for a long time. It can be seen that the role of thermal relay and fuse is different, thermal relay can only be used for overload maintenance and can not be used for short-circuit maintenance, while fuse can only be used for short-circuit maintenance and can not be used for overload maintenance. In a well-developed control circuit, especially in a motor with a large capacity, both types of maintenance should be available.
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Analysis of 10 reasons for frequent tripping of Schneider leakage switches
1. Defective device
If the lead wire of each pile head is not firmly connected and loosened for a long time, it will cause the pile to heat and oxidize, burn out the outer insulation of the wire, and announce sparks and burnt smell, resulting in undervoltage of the line and air switch action.
2. Leakage switch with ...
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Schneider circuit board maintenance work commonly used instrumentation
Before preparing to do circuit board repair work, you should prepare some things and appearances to help repairers better carry out circuit board repair operations, according to our circuit board repair training center for many years of experience has shown that prepare some necessary circuit board repair things and appearance, to be able to reach ...
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Schneider PLC control cabinet installation wiring method
(1) When placing signal cables with different properties into the same conduit, they must be isolated
(2) Try to avoid accommodating multiple power cords in the same conduit. When it is necessary to set up, a partition should be placed inside the conduit and the partition should be grounded.
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Schneider DC air open up plus or minus? How to connect the incoming and outgoing lines?
The air switch is divided into the upper inlet line and the lower inlet line of the power supply, 1 is - 3 is + 2 is + 4 is - when the upper line is inlet, 2 is + 4 is - This is related to the internal trip curve.
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How can industry be high-quality and sustainable? - Schneider
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Schneider instrumentation maintenance precautions
1. When assembling and adjusting the appearance, the original position should be recorded for rehabilitation.
2. When repairing the appearance of precision instruments, if you accidentally bounce small parts away, you should first determine the position where you can fly down.
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Schneider Instrumentation Classification
1. Industrial automation appearance and control system. This is generally referred to as PA, FA in foreign countries. PA is called process automation, and FA is called factory automation. The appearance and control system used in process automation and factory automation belong to this category, and some parts of the appearance of analytical instruments and electrical instruments also belong to the ...
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Precautions for the use and maintenance of instruments and meters - Schneider
Attention should be paid to the following matters during the use and maintenance of the appearance of the instrument:
1. Don't blindly knock and bump when overhauling, so as not to expand the problem, and the more you repair, the worse it will become.
2. Do not plug and unplug various control boards and plugs with electricity. Due to the power-on ...
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Introduction to Schneider limit switch series
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Light and medium load use;
Waist-shaped device holes for easy adjustment of mechanical errors;
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Analysis of common problems of Schneider inverter
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Because the maximum output frequency parameter of the inverter is "TFR", the factory default value is 60Hz. So when the inverter output is 50Hz, the analog output is 16mA. At this time, only ...
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The difference between high voltage and low voltage of Schneider inverter
1. What is the difference between high-voltage inverter and low-voltage inverter?
Frequency converters can be broadly divided into two categories: high-voltage frequency converters and low-voltage frequency converters.
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Schneider diode selection experience and substitution method
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Point-contact germanium diodes are generally used for detection diodes, such as 2AP series. When selecting, the detection diode with high operating frequency, small reverse current and large forward current should be selected according to the specific requirements of the circuit. Although the detection and rectification of ...
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Schneider instrumentation maintenance precautions
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Design and calculation method of inverter braking resistance - Schneider
1. The number of braking resistor boxes is roughly calculated as: motor power (KW)/11.2 (take the upper limit of the integer).
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conf→400-
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Line leakage detection method - Schneider
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Advantages of Schneider molded case circuit breaker
The contact orientation is 100% secure
As for the circuit breaker, the indication of the handle can also be said to be the fault indicator of the circuit breaker, if it is "blurred" for a while, it may cause irreparable damage. Therefore, according to the requirements of the national standard, in any case, the hand of the circuit breaker ...
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(1) Caused by incorrect parameter setting.
If the acceleration time of the inverter is set too short, the change of the output frequency of the inverter far exceeds the change of the motor frequency, and when the inverter is started, it will trip due to overcurrent. Adjusting the acceleration time accordingly to different load conditions can eliminate this problem.
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Schneider miniature circuit breaker code calling
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