Home decoration, the circuit problem is more important, especially now more and more appliances used in the home, so the leakage protector is a must, can have a good protection, what is the leakage protection device wiring diagram What are the wiring methods and precautions of the leakage protector?
Earth leakage protector wiring diagram:
Leakage protector wiring method:
1, according to different electrical equipment power supply methods choose different leakage protection
Single-phase 220V power supply of electrical equipment, should use two-pole or two-pole unipolar leakage protection device.
Three-phase three-wire 380V power supply of electrical equipment, should use three-pole leakage protection.
Three-phase four-wire 380V power supply of electrical equipment or single-phase equipment and three-phase equipment sharing circuit, should use three-pole four-wire or four-pole four-wire leakage protection.
2. According to the normal leakage current of the electric circuit, select the rated leakage current of the leakage protection device
When selecting the rated leakage action current value of the leakage protector, full consideration shall be given to the normal leakage current value of the protected line and equipment.
The rated leakage current of the selected leakage protector shall be less than 2 times the maximum value of the normal leakage current of the electrical line and equipment.
The rated voltage, rated current, short-circuit breaking capacity, rated leakage current, and breaking time of the leakage protector shall meet the requirements of the protected power supply line and electrical equipment.
Leakage protector wiring error mode:
1. When used for branch line protection, each branch line should have its own dedicated zero line, and the zero lines of two adjacent branch lines must not be connected. If the two branch lines are connected, the currents in the neutral line flow to each other, destroying the working current balance in the zero-sequence current transformer, and causing the leakage protector to malfunction. If you want to use the zero line of the power branch line as the neutral line of the lighting branch line, you will cause the leakage protector of the power branch line to operate.
2. A power-consuming device can only be connected to one branch of the protection branch. It must not be connected across the two branch circuits. It must not be connected to the front of the zero-sequence current transformer. It must not be powered by the 1-wire system. Otherwise, it will cause leakage. The protector malfunctions.
3, equipped with leakage protection device and not equipped with electric leakage protection device, shall not share a grounding device. For example, when the insulation of the motor M1 is damaged and the shell is charged, the outer shell of the motor M2 is also electrified. Since the current does not pass through the leakage protector, leakage protection is not performed.
4. Single-phase loads should be distributed as evenly as possible. If the distribution is uneven (for example, if the phase of a phase is long and the equipment is concentrated), the phase of the load is heavier, and the leakage current is larger. Therefore, the unbalanced leakage current of the three-phase mains increases, and when it reaches a certain value, it will make the trunk. The head-end leakage protector moves.
5. The protected circuit (including the working neutral line) shall pass through the through-holes of the zero-sequence current transformer and the leakage protector. The three-pole leakage protector shall not be used in place of the four-pole, three-phase, four-pole or leakage protector. If it is a three-phase, five-wire system, the protective ground wire must not pass through the transformer of the leakage protector, but must be connected to the zero line or the repeated grounding electrode at the front end (incoming terminal) of the first pole leakage protector.
Leakage protector connection method notes:
1. The neutral side of the load protector's load side must not be shared with other circuits.
2. When the leakage protection device is marked with the load side and the power supply side, the wiring shall be installed according to the regulations, and shall not be reversed.
3. Install a leakage protector with short-circuit protection. Ensure that there is sufficient arcing distance in the arc discharge direction. The size of the arcing distance is determined by the manufacturer of the leakage protector.
4. The neutral line and the protection line must be strictly distinguished during installation. The neutral line of the three-pole four-wire or four-pole leakage protector should be connected to the leakage protector. The neutral conductor that passes through the leakage protector must not be used as a protection line, and it must not be repetitively grounded or connected to the conductive leakage part of the device. The protection line must not be connected to the leakage protection device.
Leakage protector wiring diagram, leakage protector wiring method and precautions are shared here with everyone. Leakage protectors are required in the home. This is an important protection for us when using home appliances.
1, thermal relay
Thermal relays are also called thermocouples. When the load current flows through the heat-generating element (a kind of alloy resistance plate, which generates concurrent heat dissipation when passing through the current), the expansion element near it is heated. The expansion element is formed by welding two metal sheets with different expansion properties along the entire surface and is called a bimetal sheet. The lower metal sheet of the bimetal has a larger coefficient of expansion. When exceeding a certain current, the heat of the heating element bends the bimetal upward, thus causing the mechanism to deflect, and the contacts in the control circuit are disconnected, so that the main contact of the contactor is disconnected and the load circuit is cut off.
2, the control button
The control button is a main control device with a simple structure and a wide range of applications. It is a manual master device that is used to switch on or short-circuit a small current circuit during a period of time.
3, the middle relay
Intermediate relay: Used in relay protection and automatic control systems to increase the number and capacity of contacts. It is used to pass intermediate signals in the control circuit. The structure and principle of the intermediate relay is basically the same as that of the AC contactor. The main difference with the contactor is that the main contact of the contactor can pass a large current, while the contact of the intermediate relay can only pass a small current. Therefore, it can only be used in control circuits. It is generally without a main contact because the overload capacity is relatively small. Therefore, all of it uses auxiliary contacts and the number is relatively large. The new national standard defines K as the intermediate relay and KA as the old national standard. It is usually a DC power supply. A few use AC power.
4, contactor
The working principle of the DC contactor is as follows: When the contactor coil is energized, the coil current generates a magnetic field, so that the static iron core generates an electromagnetic suction to attract the moving iron core and drive the contact action: the normally closed contact is open, the normally open contact is closed, and the two The players are linked. When the coil is de-energized, the electromagnetic suction force disappears and the armature is released under the action of the release spring to restore the contact: the normally open contact opens and the normally closed contact closes.
The working principle is the same as that of the AC contactor. The difference lies in that the attraction coil of the AC contactor is powered by the AC power supply, the attraction coil of the DC contactor is powered by the DC power supply, and because the DC contactor coil is DC, the DC has no instantaneous value. At any time, the effective value is equal, there is no zero crossing, so the DC contactor armature does not need to install a short-circuit ring that prevents the zero-point voltage from generating a low suction force and causes the contactor to vibrate loudly.
5, universal switch
It is a multi-position, multi-stage, and multi-circuit control master. When the operating handle is rotated, the cam inside the switch is driven to rotate, so that the contacts are closed or disconnected in a predetermined order.
Universal switch is mainly used for the conversion of various control lines, voltmeter, ammeter commutation measurement control, switching and remote control of distribution equipment lines. Universal switch can also be used to directly control the start, speed, and commutation of small-capacity motors.
Commonly used products are LW5 and LW6 series. The LW5 series can control small-capacity motors up to and including 5.5kW; the LW6 series can only control small-capacity motors up to 2.2kW. For reversible operation control, reverse starting is allowed only after the motor is stopped. LW5 series universal switch can be divided into two types: self-resetting and self-positioning. The so-called self-resetting means that when the handle is toggled in a certain gear position, the handle is automatically returned to its original position after the hand is released; the positioning type means that when the handle is placed in a certain position, it cannot automatically return to its original position and stops at the position. This stall.
The handle operation position of the universal changeover switch is represented by an angle. The handles of different types of universal transfer switches have different universal transfer switch contacts, and the graphical symbols in the circuit diagram are shown in FIG. 2 . However, since the contact state of the contacts is related to the position of the operation handle, in addition to drawing the contact graphic symbols in the circuit diagram, the relationship between the operation handle and the contact state of the contacts should also be drawn. When the universal switch is turned to the left by 45°, the contacts 1-2, 3-4, 5-6 are closed and the contacts 7-8 are opened; when the switch is turned to 0°, only the contacts 5-6 are closed, right At 45°, the contacts 7-8 close and the rest open.
6, low voltage circuit breaker
Low-voltage circuit breakers, also known as automatic switches, are appliances that have both manual switching and automatic voltage loss, undervoltage, overload, and short circuit protection. It can be used to distribute electrical energy, starting asynchronous motors infrequently, and protecting the power lines and motors. When they are severely overloaded or short-circuited and under-voltage faults, they can automatically cut off the circuit. Their functions are equivalent to fuse-type switches and Overheating relays and other combinations. In addition, after breaking the fault current, it is generally not necessary to change components, and it has been widely used.
Structure and working principle Low-voltage circuit breakers consist of operating mechanisms, contacts, protection devices (various trip units), and arc extinguishing systems. The main contacts of the low-voltage circuit breaker are manually operated or electrically closed. After the main contact is closed, the free tripping mechanism locks the main contact in the closing position. The coil of the overcurrent release and the thermal element of the thermal release are connected in series with the main circuit and the coil of the undervoltage release is connected in parallel with the supply. When the circuit is short-circuited or severely overloaded, the armature of the over-current release pulls in, causing the free tripping mechanism to act, and the main contact opens the main circuit. When the circuit is overloaded, the thermal element of the thermal release heats up to bend the bimetal and push the free tripping mechanism. When the circuit is under voltage, the armature of the undervoltage release releases. The free trip mechanism is also actuated. The shunt release is used as a remote control. In normal operation, the coil is powered off. When a distance control is required, the start button is pressed to energize the coil. The armature drives the free trip mechanism to make the main touch. Disconnect.
7, isolation switch
Isolating switch is the most widely used electrical appliance in high-voltage switchgear. Its working principle and structure are relatively simple. However, due to the large amount of use and high work reliability, the design, establishment and safe operation of substations and power plants are required. The impact is large. The main characteristic of the knife gate is that it has no arc extinguishing ability, and it can only divide and combine circuits without load current. The main role is:
1) After the gate is opened, establish a reliable insulation gap, and separate the equipment or circuit that needs to be repaired from the power supply with a distinct disconnection point to ensure the safety of the maintenance personnel and equipment.
2) According to operating needs, change the line.
3) It can be used to separate and combine small currents in the line, such as the charging current of bushings, busbars, connectors, and short cables, the capacitive current of the switching voltage-sharing capacitor, the circulating current when the double busbar is switched, and the excitation current of the voltage transformer. Wait.
4) According to the specific conditions of different structure types, it can be used to divide and combine the no-load excitation current of a certain capacity transformer.
Outdoor knife gates can be divided into single-column, double-column and three-column, depending on the structure of their insulating pillars. Among them, the single-column type knife gate directly uses the vertical space as the electrical insulation of the fracture under the overhead busbar. Therefore, the obvious advantage is that it saves the floor area, reduces the number of lead wires, and the state of the closing and closing is particularly clear. In the case of ultra-high voltage transmission, the use of a single-column type knife gate in substations will have an even greater effect in saving floor space.
In low-voltage equipment, it is mainly applied to low-voltage terminal distribution systems such as houses and buildings. The main function: with load breaking and connected line isolation function.
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