1. Short-circuit protection When a short circuit occurs, the main circuit is cut off by the fuse of the fuse FU. In order to expand the protection range, the fuse is as close to the power supply as possible in the line, and is generally installed directly under the knife switch. 2. Overload prote... read more
The essential difference between a programmable controller and a traditional relay control system is the use of the scanning mode and the concept of a relay. PLC system design includes two parts: hardware design and software design. The design method of parallel development of hardware and software... read more
The contactor is an automatic electromagnetic type electric appliance, which is suitable for frequently connecting and disconnecting AC and DC main circuits and large-capacity control circuits over long distances. It is mainly used in automatic control of AC and DC motors, electric heating equipmen... read more
The synchronous speed of the motor n = 60 f / P. When the grid frequency f is fixed, n is inversely proportional to the number of pole pairs P. If the number of pole pairs P can be changed, then n will also change. Pole-changing speed regulation is only applicable to cage asynchronous motors. Multi... read more
The contact system is the actuator of an electrical appliance, and it functions to open and close the circuit. Therefore, the quality of the contacts directly affects the working performance of the entire appliance. There are many types of contact mechanisms, and according to their contact types, t... read more
Power system dispatching automation collects real-time information on the operation of the power system through the remote terminal (RTU) installed in each power plant and substation, and transmits it to the dispatching master station (MS) via the communication channel. Perform safety analysis, loa... read more
According to the size of the relay: 1) Miniature relays: relays with the longest side dimension not greater than 10 mm. 2) Ultra-compact miniature relays: relays with the longest side dimension greater than 10 mm, but not greater than 25 mm. 3) Miniature relays: relays with the longest side dimensi... read more
Low-voltage circuit breakers are also called automatic air circuit breakers, or automatic switches for short. Low-voltage circuit breakers are functionally equivalent to a combination of knife switches, fuses, thermal relays, and undervoltage relays. Their function is not only to frequently turn on ... read more
There are many electrical control methods for equipment, including relay contactor control, non-contact logic control, programmable controller control, computer control, etc. In short, the reasonable determination of the control plan is an important prerequisite for the realization of a simple, reli... read more
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