Chapter 6 Automotive Electrical and Electronic Systems
6.1 Lead Acid Battery and Circuit protection
devices
All of the vehicle fuses are usually contained in a holder called fuse block or relay block (Figure 6-2 and 6-3).
Figure 6-1 Battery construction
Chapter 6 Automotive Electrical and Electronic Systems
Chapter 6 Automotive Electrical and
ElectronBattery and Circuit protection devices 6.2 Charging System 6.3 Starting System 6.4 Ignition Systems 6.5 Lighting System 6.6 power window system 6.7 Supplemental Restraint Systems 6.8 Cruise control systems 6.9 Anti Theft Systems 6.10 Air Conditioning
Chapter 6 Automotive Electrical and Electronic Systems
6.1 Lead Acid Battery and Circuit protection devices
electrochemical overload fusible relay bimetallic strip
remainder
exceed
New Words
[i¸lektrəu'kemikəl] a.电化（学）的
['əuvə'ləud] ['fju:zəbl] ['rilei] [¸baimi'tæ lik] [strip]
[ri'meində]
[ik'si:d]
n.超载，过载，过负荷 a.易熔的，可熔化的 n.继电器 a.双金属的 n.条，带 n.剩余物，其余的人；a. 剩余的 v.超过，胜过
Chapter 6 Automotive Electrical and Electronic Systems
6.1 Lead Acid Battery and Circuit protection
devices
6.1.1 lead-acid storage battery A lead-acid storage battery (Figure 6-1) is an electrochemical device that produces voltage and delivers electrical current. The battery is the primary "source" of electrical energy used in vehicles today. When charging, the battery converts electricity into chemical energy, and when discharging, it converts chemical energy into electricity, producing a current. 6.1.2 Circuit protection devices It is necessary to protect electrical circuit against shorting (accidentally touching ground) that could burn up the wiring. Electrical units must be protected against overloads also. In circuits, Circuit protection devices must be installed in series with the electrical devices or wiring to be protected. The common types of circuit protection devices are fuse, fusible link and circuit breaker, see Table 6-1.
A circuit may be protected by a special wire that acts as a fuse. This wire is called a fusible link.
A Circuit breaker feeds current through a bimetallic strip and a set of points to the remainder of the circuit. When the current exceeds the breaker’s rating, the bimetallic strip heats and bends to separate the points. Once it cools, it will close the circuit.
Relays are used to direct large current flows that might overheat and damage a switch, they are a type of solenoid switch that closes electrical contacts. Most of relays are usually contained in relay block and junction block (J/B).