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High and low voltage switchgear

2019-09-26

Hello, there are usually rolling capacitor compensation cabinets that can be used together with high and low voltage switchgear.

Alias, local capacitor compensation cabinet.

Soft starters for high and low voltage switchgear usually have voltage transformers, voltage transformers, AC contactors, operating voltage valid periods, and live displays.

The condition of the motor soft start cabinet must be used.

1. The transformer used in the processing plant has a very large capacity, and the motor starts a large amount of current, which jeopardizes the normal operation of other power-consuming machines and equipment, and even seriously jeopardizes the safety of the transformer.

2, the power grid is not stable or the power network pressure drop is large, the motor is difficult to start, the high-low voltage switchgear soft start must be applied to reduce the amount of starting current, so that all normal starting and running, no harm to the power network.

3, such as power mills, crushers, rolling presses, centrifugal pumps, refrigeration compressors, centrifugal fans and other machinery and equipment load is too heavy, the motor is often difficult to start.

4, start with a frequency sensitive varistor, often damage the frequency sensitive package, start with auto-coupling blood pressure, the actual effect is not very good.

5. When the motor starts, the amount of easy starting current is too large and the motor is burnt.

6. When constructing, rebuilding or renovating the production line.

7, high- low voltage switchgear soft start cabinet when the starter is upgraded.

Soft starter (soft starter) This kind of motor soft start, soft parking, light load, environmental protection and energy saving and various maintenance functions are integrated into the motor control equipment.

The starting characteristics of the asynchronous motor are two key values, the starting current amount and the starting torque. The soft starter is the starting voltage of the switching power supply that is added to the motor according to the change, so as to reduce the starting current and start the turning. distance

The characteristics of the number of soft starters can reasonably limit the inrush current, prevent the extra impact torque and its impact on the Internet of the power distribution equipment, and reasonably reduce the false opening posture of the route knife switch and the AC contactor; The stopped motor can reasonably manipulate the temperature of the motor and greatly increase the service life of the motor. At present, the application is relatively common. The general soft starter in the project has a soft starter of water resistance cabinet (soft starter for liquid resistor), soft start of solid state hard disk, soft start of magnetic control, soft start of rolling DC frequency conversion. The soft start principle of the water resistance cabinet is for the winding motor:

In the motor rotor control loop of the winding motor, a unique configuration of the lithium battery electrolyte is used as a resistor. According to the adjustment of the concentration value of the lithium battery electrolyte and changing the spacing between the two boards, the resistor of the series resistor is activated. Throughout the whole process, the characteristics of the motor mechanical equipment are considered to be the string resistance value, so that the motor can be arbitrarily increased speed and stably started under the condition of obtaining large starting torque and minimum starting current. Short-circuit motor rotor control after starting The circuit is used to start the motor.

For cage motors:

Cage motor water resistance cabinet is a special material solution used as a resistor. In the unique design scheme of the pressure liquid resistance box, the pole piece is introduced into the electric level, and is connected into the motor stator control circuit. When the motor starts, according to the liquid The resistance and start-up time control keeps the smooth and non-impacting blood pressure of the squirrel cage motor. The solid-state hard disk soft-start principle uses a thyristor to turn on the power supply circuit to reduce the operating voltage applied to the motor, and then gradually increases the operating voltage and current amount of the motor to increase the motor torque according to the gradual operation until the motor accelerates to a fast speed. . This type of starting method can reduce the amount of starting shock current of the motor and reduce the impact on the power grid and the motor itself. Together, it also reduces the impact of the mechanical equipment of the mechanical equipment load equipment on the motor to increase the service life of the equipment, reduce the common faults and shutdown maintenance time. The magnetic soft start is based on the closed-loop control system, and the auto-coupling DC excitation regulator is adjusted. The size of the alternating current in the winding, smooth changes the inductive reactance of the magnetron reactor, so that the inductive reactance is reduced from large to small fully automatic in the reserved time, keeping the motor soft start. The rolling soft-start soft-start high-voltage inverter soft start is an electromagnetic energy control device that converts the DC switching power supply into another frequency by using the conduction function of the power engineering integrated circuit process, and the DC variable frequency operation can maintain the smooth starting and speed regulation of the motor. The variable speed coverage is wide, high efficiency, and it maintains the soft start, over current, over voltage and over voltage protection of the asynchronous motor. The technical principle of AC motor speed control shows the key solutions for improving product quality and production volume, environmental protection and energy saving, energy saving, improving load and improving economic benefits.


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