Electrical control systems are generally referred to as secondary control circuits for electrical equipment. Different equipment has different control circuits, and the control methods for high-voltage electrical equipment and low-voltage electrical equipment are also different. Specifically, an electrical control system is a combination of several electrical components used to control one or more objects, thereby ensuring the safe and reliable operation of the controlled equipment. Its main functions include: automatic control, protection, monitoring, and measurement.
What are the components of an electrical control system? The basic circuit of a commonly used control circuit consists of the following parts.
1. Power supply circuit: The power supply circuit can be supplied with various power sources such as AC380V, 220V and DC24V.
2. Protection Circuit: The working power supply of the protection (auxiliary) circuit can be single-phase 220V AC, 36V DC, or DC 220V AC, 24V DC, etc. It provides various protections for electrical equipment and lines, such as short circuit, overload and undervoltage. It is composed of protection components such as fuses, thermal relays, undervoltage coils, rectifier components and voltage regulator components.
3. Signal circuit: A circuit that can promptly reflect or display information about the normal and abnormal working status of equipment and lines, such as signal lights of different colors, audio equipment with different sounds, etc.
4. Automatic and Manual Circuits: To improve work efficiency, electrical equipment is generally equipped with automatic circuits. However, during installation, commissioning, and emergency handling, manual circuits are also necessary for debugging. Switching between automatic and manual modes is achieved through combination switches or changeover switches.
5. Braking and stopping circuit: The control link that cuts off the power supply to the circuit and takes certain braking measures to stop the motor quickly, such as energy consumption braking, power supply reverse connection braking, reverse connection braking and regenerative braking.
6. Self-locking and interlocking circuits: A self-locking circuit is an electrical mechanism that keeps the circuit energized and allows the electrical equipment to continue operating after the start button is released. For example, the normally open contact of a contactor is connected in series in the coil circuit. An interlocking circuit is a protective mechanism that ensures the safe and reliable operation of two or more electrical devices and components, allowing only one to be energized and start while preventing the other from starting. For example, the normally closed contacts of two contactors are connected in series in the coil circuit of the other contactor.
