Wuhan molded case circuit breaker selection manual

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Wuhan molded case circuit breaker selection manual; Through the relay, the zigzag test of one control signal controlling another or several signals can be realized: when the zigzag reaches 90 degrees under the specified bending center diameter,

Wuhan molded case circuit breaker selection manual can be used as the position limit switch of mechanical equipment, and can also be used to detect whether iron doors, windows, etc. are in the specified position

optical relay

optical relay is a semiconductor relay used for ac/dc, which refers to a device integrating light-emitting devices and light receiving devices

the type of fuse is mainly selected according to the protection characteristics of load and the size of short-circuit current. For motors and lighting branch lines with small capacity, fuses are often used as overload and short-circuit protection, so the melting coefficient of the melt is expected to be appropriately small. RQA series fuse with lead tin alloy melt is usually selected. For motors and lighting mains with large capacity, the short-circuit protection and breaking capacity shall be emphatically considered. h) Process realization: the experimental process, measurement, display and analysis are all completed by microcomputer step 2: slow loading; Generally, RM10 and RL1 series fuses with high breaking capacity are selected; When the short-circuit current is large, RT0 and rtl2 series fuses with current limiting effect should be used. The rated current of the melt can be selected according to the following methods:

the melt of the fast fuse is made of pure silver. Because of its low resistivity, good ductility and good chemical stability, the melt of the fast fuse can be made into thin sheets and has a round hole narrow neck structure. In case of short-circuit fault, the current density at the narrow neck is high, so the narrow neck is fused first and divided into many small sections by quartz sand. In this way, the formed by melt fusing is divided into many small sections by quartz sand. The current is small, the distribution space is small, and it is easy to be absorbed by arc extinguishing agent. Because the quartz sand is insulated, an insulator is formed immediately after extinguishing to break the circuit

characteristics of fast fuse

1. When protecting stable loads without starting process, such as lighting lines, resistors, electric furnaces, etc., the rated current of the melt is slightly greater than or equal to the rated current in the load circuit

2. The melt current of the motor protecting a single long-term operation can be selected according to the starting current or the following formula:

irn ≥ (1.5 ~ 2.5) in

where irn-- the rated melt current; In-- rated current of motor. If the motor starts frequently, the coefficient in the formula can be appropriately increased to 3 ~ 3.5, which shall be determined according to the actual situation

3. Protect multiple long-term motors (power supply mains)

irn ≥ (1.5 ~ 2.5) in all indoor pavilions are full! "We need to build more and more outdoor temporary pavilions Max+ σ In

3) integrated signal: for example, when multiple control signals are input to the multi winding relay in the specified form, the predetermined control effect is achieved through comparison and integration

4) automatic, remote control and monitoring: for example, the relay on the automatic device and other electrical appliances can form a program control circuit to realize automatic operation

main classification

1. classification according to the working principle or structural characteristics of the relay

1) electromagnetic relay: use the circuit in the input circuit in the electromagnet iron core


7) polarization relay: a relay with the combined action of polarization magnetic field and control current through the magnetic field generated by the control coil. The action direction of the relay depends on the direction of the current flowing through the control coil

8) other types of relays: such as optical relay, acoustic relay, thermal relay, instrument relay, Hall effect relay, differential relay, etc

2. Classification according to the overall dimensions of relays

1) miniature relays

2) Ultra Miniature miniature relays

3) miniature miniature relays

note: for sealed or enclosed relays, the overall dimensions are the dimensions of the relay body in three mutually perpendicular directions, excluding the dimensions of mounting parts, lead out ends, ribs, flanging, and sealing solder joints

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