Wires, harnesses, fuses, connectors, switches and relays are all essential components of automotive circuits, the basic components of automotive circuits. Today Xiaobian comes to popularize their basic knowledge.
WireThe wires have low voltage wires and high voltage wires.
Line selection factors: insulation, current through the size and mechanical strength. And the application conditions are different, and each of the three factors has its own focus, for example:
High-voltage circuit: According to the insulation requirements of high voltage resistance of thousands to tens of volts, the wire with small core cross-section but thick insulation cladding is used.
Low-voltage circuit circuit: selected according to the working current magnitude and mechanical strength. As the number of electrical appliances used in automobiles increases, the number of wires increases. For ease of installation and overhaul, a two-color line is used, the primary color is the base color, and the secondary color is the strip ribbon or spiral ribbon of the loop fabric, and the main color is marked. Before, the secondary color is behind.
Wire color and representation
2. Wire harnessIn the car, in order to make the line clear, easy to install and protect the wire insulation, in addition to the high-voltage line and the battery wire, the car wire is wrapped with an insulating material such as a thin polyvinyl chloride tape, which is called a wire harness.
When installing the harness, the following precautions should be taken:
(1) The wire harness is fastened with a circlip and a dowel to prevent loosening and grinding;
(2) The wire harness at the corner or the part that has moved relative to it should not be pulled too tightly.
(3) Apply rubber, felt mats or casings through the hole and around the acute angle to protect them from wear and tear, causing grounding, short-circuiting and even fire;
(4) Each terminal must be connected reliably and in good contact.
3. ConnectorThe connectors can be divided into the following categories: the first type is the connection harness and the electrical components; the second type is the connection harness and the harness; the third type is the connection between the harness and the body; the fourth type is the transition connection, which needs to be connected in the connector. The wires are connected by shorting terminals.
In order to facilitate wiring, the wire ends of each wire end of the automobile wiring harness are welded with a wiring card, and the insulating pipe is sleeved at the connection between the wire and the wiring card, and the frequently removed wiring card generally adopts an open type, and the wiring card with less disassembly opportunities is often adopted. Closed, as shown.
1) Relay
The relay has two types of function relays and circuit control relays. Such as flash relay, wiper intermittent relay is a functional relay. Circuit control relays are common in automobiles, such as headlight relays, fog light relays, start relays, horn relays, and load-shedding relays. Its function is to control the relay through the small current of the switch. After the relay contact is closed, the large current is directly supplied to the electric appliance, and the protection switch contact is not ablated.
When relays are distinguished by structural principle, there are mainly electromagnetic relays, reed relays, bimetal relays, and electronic relays. The relay is divided into normally open type, normally closed type and open and close mixed type according to the contact state. The relay is divided into two types according to the shape: round and square; according to the number of pins, it is divided into 3 feet, 4 feet, 5 feet and so on. According to the contact state, it is divided into normally open type, normally closed type and open and close mixed type. Most of the relays use electromagnetic relays consisting of electromagnets and contacts.
The shape and internal principle of common relays are shown in the figure.
2) Circuit protection device
The automobile circuit protection device is used to automatically cut off the circuit when the line or electrical equipment is short-circuited or overloaded to ensure the safety of electrical equipment and lines. Circuit protection devices commonly used in automobiles include fusible wires, circuit breakers, and fuses (chips).
Common symbols for three circuit protection devices such as fusible wires, circuit breakers and fuses are shown in the figure.
Common symbolic fusible link for circuit protection devices
Fuse (fuse) use note:
(1) After the fuse is blown, the cause of the fault must be found first and completely eliminated.
(2) When replacing the fuse, it must be the same as the original specification, especially if the fuse is larger than the specified capacity, otherwise the protection will be lost.
(3) Poor contact between the fuse holder and the fuse will cause voltage drop and heat generation. Therefore, special attention should be paid to checking for oxidation and contamination. If there is dirt and oxides, it should be polished with fine sandpaper to make it in good contact.
Magnetic Transducer,Smd Magnetic Transducer,Buzzer Magnetic Transducer,Magnetic Transducer Buzzer
NINGBO SANCO ELECTRONICS CO., LTD. , https://www.sancobuzzer.com