What is an Electric Control Cabinet? Requirements for Electric Control Cabinet


The electric control cabinet is the equipment used in each power generation, distribution and substation.


Electric control cabinet is to assemble switchgear, measuring instrument, protective device and auxiliary equipment in closed or semiclosed metal cabinet or on screen width according to electrical wiring requirements, and its layout should meet the requirements of normal operation of power system, and is easy to overhaul and does not endanger people. A safe control cabinet (box) for personal and surrounding equipment. Including (distribution cabinet) (distribution box) (electrical control cabinet), etc., the circuit can be connected or disconnected by manual or automatic switch during normal operation.


Cut off the circuit or alarm with the help of protective electrical appliances in case of failure or abnormal operation. Various parameters in operation can be displayed by means of measuring instruments, and some electrical parameters can also be adjusted to prompt or send out signals for deviations from normal working conditions. Commonly used in various power generation, distribution and substations.


electric control cabinet


1. Requirements for electric control cabinet


Generally, the secondary line of low-voltage electric control cabinet, the minimum wiring cross-sectional area of the voltage line is 1.5 square meters, and the minimum cross-sectional area of the current loop is 2.5 square meters. The current signal line, etc., flows a current of 5 amps. In addition, the power line is yellow, green and red, and the zero line is blue or light blue (some are gray. Because international standards are also distinguished as European standards or American standards). The black line of the main line of the circuit is at least 1.5 square millimeters, the red line of the control line AC voltage 1.0 square, and the blue line of DC voltage 1.0 square. The signal line color is not required.


2. Standards for electric control cabinets


Some electric control cabinets have standards. It is called standard cabinet, GGD. The standard electric control cabinet implements the following standards: "GB50054-1995" low-voltage electrical appliance design specification, "GB50055-1993" general electrical equipment design specification, "GB50303-2002" industrial automation instrument engineering construction design specification, "GB7251-97" low-voltage complete set Control equipment for switchgear, "GB50171-97" Specifications for Construction and Acceptance of Electrical Installation Engineering Panels, Cabinets and Secondary Circuit Wiring", but most of the electric control cabinets are not standard. The reason for the non-standard is that when you do the project, according to In reality, how big a cabinet should be. Standard cabinets are sometimes too large to be practical.


3. Model compilation of electric control cabinet


3.1 Technical performance
3.1.1 Power supply voltage: AC380V, 50Hz
3.1.2 Control objects: three-phase asynchronous motors not greater than 320 kilowatts.
3.1.3 It can work reliably under the following conditions:
Altitude does not exceed 1000 meters.
The ambient temperature is not higher than 45°C and not lower than -30°C.
The relative humidity of the air is not more than 85% (20°C ± 5°C).
In non-explosive medium, and without conductive dust and corrosive gas.


3.2 Debugging and usage
The control circuit of this series of control cabinets (boxes) has both automatic control and manual control, and also has over-current, over-voltage, under-voltage, phase loss protection and accident reporting functions. Before using this product, it must be controlled according to the electrical schematic diagram. After rechecking the wiring, adjust the setting values ​​of the corresponding components according to the actual requirements of the motor, and then start.


3.2.1 Automatic operation: Turn on the power, the power indicator light is on, turn the transfer switch to the "automatic" position, and check whether the motor controlled by the control cabinet (box) operates according to the instructions of the liquid level controller. When the liquid level reaches the control liquid level, the corresponding liquid level indicator lights up, the corresponding normally open contact of the limit control relay is automatically closed, the secondary control circuit is automatically connected, the motor is started, and the running indicator light is on at the same time. When the water level reaches the stop water level, the corresponding indicator lights up, the normally closed contact of the corresponding limit control relay of the liquid level measuring and controlling instrument is disconnected, the secondary control circuit is opened, the motor stops working, and the running indicator light goes out.


3.2.2 Manual operation: turn on the power, the power indicator light is on, turn the transfer switch to the "manual" position, press the start button, the motor starts to run, the running indicator light is on, press the "stop" button, the motor stops, and it runs The light turns off.


3.2.3 Regardless of the control method adopted, when the limit water level is reached, the over-limit water level signal contact is connected, the secondary control circuit is de-energized, the motor stops running, and an audible and visual alarm signal is issued. If there is an accident during the operation of the motor, the accident indicator light will be on, and the electric bell will automatically report suffering. At this time, press the stop button to force the motor to stop working.


3.3 Ordering Information Electric Control Cabinet

3.3.1 The model and specification of the ordered product, and the model, specification and control method of the liquid level display and controller.
3.3.2 The model, power, rated current and number of motors to be equipped, the requirements for indicator light setting and instrument display requirements.
3.3.3 If there is a non-standard power transmission control cabinet (box), it can be negotiated and determined when ordering.

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