电路保护介绍

蓝黑军团

电路保护
Circuit Protection
什麽是电路保护？
What is circuit protection?
在电学中，我们把电路中超额的电流称为过量电流。过量电流，因为它们已经超
过了指定数值，所以被视为是不正常的。我们的客户正在寻求方法来减低或者避
免这种可能引起灾害的过量电流。电路保护设备就能阻止这种过量电流引起灾
害。
In an electrical circuit, we refer to an excess (FLA)flow of current as an overcurrent.
Overcurrents, since they exceed design or rated values, are considered abnormal. Our
customers look for ways to limit or interrupt these overcurrents, which (If allowed
through equipment)may cause damage. Circuit protection equipment provides our
customers with the means to prevent the damage.
为什麽客户会需求这种电路保护？
Why do our customers require circuit protection?
过量电流的保护是非常必须的，因为它可以阻止一个微小的、可控问题发展成为
一个更大的问题。潜在的有危害性的过量电流可以导致引起一个过量电压，部件
损伤或者短路事故。过量电流会导致负载过热。这种超过正常水平的热度也许会
破坏其他部件，或者导致火灾。如果没有过电流保护，当负载增加时相应就需要
更多的电流，直到最後这个设备会燃烧起来。通常就会引起火灾。因此，象UL、
csa、vde 等安全协会要求在绝大多数设备上装置过电流保护。
Overcurrent protection is necessary in order to prevent a small, controllable problem
from becoming a much larger issue. Potentially damaging overcurrents can result
form excessive voltages, component failure or an accidental shorting of a circuit.
Currents above the level the circuit was designed to handle produce excessive heat.
The higher heat level may destroy other components or producing damaging heat.
Most electric and electronic devices cannot distinguish between normal loads or
overloads. Without circuit protection, these devices would draw more currents as the
load increased, until finally the equipment burned itself out. Danger of fire is always a
possibility. For these reasons, safety agencies such as th UL,CSA, VDE require circuit
protection on most equipment. The faulty circuit must be interrupted for protection.
在过电流保护中什麽是可行的选择？
What are the choices available in equipment protection?
保险丝 fused
聚酯产品 polymer products
温度过电流保护器 thermal circuit breakers
磁性过电流保护器 magnetic circuit breakers
以上这些都能起到很好的保护电路的功能，在後续的段落中会有讨论到。
All serve useful functions and have their purpose, which will be discussd in the
following pages.
I. Fuses 保险丝
保险丝这种装置在由於短路而引起发热时、有涌入电流时、或者电流过量时切断
电路。传统的保险丝在负载过荷时能自动断开，但是仅此一次，以後就需要更换
一个新的。传统保险丝的核心是一根金属线，当电流过量时能发热到它的熔点。
当金属线熔断以後电路中的电流就降低为零了。
A fuse is a device which breads the circuit under conditions such as heating by a short
circuit, sustained inrush current, or overcurrent conditions. A traditional fuse will
“provide protection from an overload by opening only once and then it needs to be
replaces. The heart of a typical fuse is a length of wire that is heated to its melting
point by the excessive current. The circuit current flow decreases to zero as the wire
melts open.”
保险丝是一种价格低廉又可靠的保护电流方式，因为就它们价格来水它们能提供
一种相对灵敏的切断电流功能。它的缺点在於它们在保护电路的同时牺牲了自
己，而且当外界温度改变或者有微量负荷过栽时会有点不过精确。
Fuses can be an inexpensive, dependable means of protecting equipment and wiring ,
since they offer relatively high current interrupting capacity for their cost.
Disadvantages to using a fuse are that they destroy themselves in the protection
process, and thy are somewhat imprecise due to the effects of ambient temperature
changes and repeated exposure to surges and minor overloads.
保险丝装置的特性是指保险丝对於不同电流负载的反应灵敏程度。根据特性可以
分为三大种类，快跳— 瞬间反应，中跳— 通过缓和高涌入电流来保护电路装置，
慢跳— 可以承受一些涌入电流。电流的等级和特性都会影响保险丝的特性，因为
有相同电流等级的保险丝可以用不同的时间— 电流曲线来表示。慢跳保险丝具有
额外的温度惯性，因此它们可以承受一些短暂的涌入电流。有关选用保险丝的一
些其他因素包括操作电流，电压（交、直流），物理尺度限定，认证（UL、CVSA、
VDE），以及过量电流，保险丝断开所需要的时间长短。
The characteristics of a fuse design refer to how rapidly the fuse responds to various
current overloads. Fuse characteristics can be classified into three general categories,
fast acting, which has virtually no delay, medium-blo, which protects devices
subjected to moderate to high inrush currents ,and slo-blo, which can withstand some
inrush current. Current rating and characteristic are both needed to define a fuse since
fuses with the same current rating can be represented by considerable different
time-current curves. Slo-blo fused have additional thermal inertia designed in so that
they can withstand inrush or transient currents. Some of the factors that are involved
in the selection of a fuse include operating current, voltage(AC or DC), physical size
limitations, agency approvals(UL,CSA, VDE, or Military),as well as overload
current(in breaking capacity)and length of time in which the fuse must be open.
II．聚酯产品 polymer products
和传统保险丝不同，聚酯保险丝通过使错误电流最小化来使电流重新稳定下来。
聚酯保险丝是由能导电的塑料（由一种绝缘的水晶和一种导电性能级好的黑炭组
成）聚集在薄薄的层片中组成，在每一面中都附有ELETRODE。这个ELETRODE
甚至可以在装置中分配电压，而且可以提供一个附加铅片的平面。这种现状使可
导电的塑料材料能被应用於重整电流以保护回路装置，因此它们展示了在受热时
非常广阔的非直线形积极温度系数（PTC）。PTC 被广泛用来评价产品的抗热特
性。
Unlike traditional fuses, polymeric fuses provide resettable circuit protection by
limiting fault current. Polymeric fuses are made from a conductive plastic(made from
a non-conductive crystalline polymer and a highly conductive carbon black)formed
into thin sheets, with electrodes attached to either side. The electrodes ensure even
distribution of power through the device, and provide a surface for leads to be
attached or for custom mounting. The phenomenon that allows conductive plastic
materials to be used for resettable overcurrent protection devices is that they exhibit
a very large non-linear positive temperature coefficient(PTC)effect when heated. PTC
is a characteristic that many materials exhibit whereby resistance increases with
temperature.
用这种聚酯产品来保护电路的好处已经得到广泛的肯定，可应用於下列工业产品
中：
the benefits of polymer products as circuit protectors have been widely recognized
and applied to the following products and industries:
通信设备 communications equipment
个人手提式电脑 personal and laptop computers
中、小型电动马达 small and medium electric motors
音像设备和扬声器 audio equipment and speakers
测试仪器 test and measurement equipment
火警系统 security and fire alarm systems
医疗设备 medical electronics
航海设备 marine electronics
装电池产品 battery-operated toys
工业控制 industrial controls
III．过电保护器 circuit breakers
过电流保护器，能应用於更高的电流装置中，可以在瞬间切断电流。这种产品的
一个好处是重复使用性。一个过电流保护器可以使用很多次。有两种类型：温度
型和磁性型。
A circuit breaker, designed for higher current applications, will interrupt the circuit
during a short circuit or inrush of current. An advantage this product offers is tis
repeatability. Circuit brakersmay be used many times. There are two types of circuit
breakers: thermal and magnetic.
A． 温度过电流保护器 thermal circuit breakers
操作原理非常简单，温度过电流保护器提供了最可靠并且有效的方式之一来保护
电流装置。它们可以很好的保护各种部件以及系统-从马达到螺旋变压器，从印
刷的电路板，到低电压的分流装置例如车辆、船只、电池供能机械。“温度过电
流保护器利用一个双金属片在电路中的跳脱来工作。热量由负荷产生，是双金属
片产生变形，跳脱，因此切断了回路。温度过电流保护器和传统的保险丝相比，
有明显的优势，他们在跳脱之後还可以再使用，而且它们也可以当作主要的
ON/OFF 开关用来保护设备。
With simple operation through the heating effect of current, thermal circuit breakers
offer one of the most reliable and cost

蓝黑军团

effective forms of protection device available.
As a result they are well-suited for the protection of a broad range of components and
systems-from motors and transformer windings, through printed circuit boards, to the
low voltage power distribution circuits of road vehicles, boats, and battery powered
machines. “thermal circuit breakers utilize a bimetallic strip electrically in a series
with the circuit. The heat generated by the current during an overload deforms the
bimetallic strip and trips the breaker. Thermal breakers have significant advantage
over traditional fuses in that they can be reset after tripping. They can also be used as
the main ON/OFF switch for the equipment being protected.
这类设备都需要有能力一方面来识别安全的开关-ON 或者电流的变换，另一方面
同样存在危害性的负载。温度过电路保护器可以承受在马达发动时产生的高电流
涌入。同时，它们为马达的锁固转子提供了保护作用。温度CBE 的特性是它们
可以和它们所要保护的部件或者系统严格匹配。这样就可以减少对过大尺寸金属
线以及连接件的需求，同时提供了可靠的保护，甚至当电流负荷不是很大其他电
路保护装置无法工作的环境下都可以动作。
Such applications all require the ability to discriminate between safe switch-on surges
or transients on one hand, and harmful sustained overloads on the other. Thermal
circuit breakers can withstand high level surges, which arise from lamp loads or
motor-starting, for example. At the same time they afford protection against the
effects of genuine failure such as motor locked rotors. The characteristics of thermal
CBE’s (circuit breakers for equipment)can be matched closely to the ratings of the
component or system they are protecting. This eliminates the need for over-sizing of
wiring and connectors, while offering dependable protection, even under low level
overcurrent conditions which cannot be adequately provided for other methods of
circuit protection.
温度CBE 用以下三种机械装置之一来充分发挥它们的功能：
thermal circuit breakers utilize one of tree different mechanisms optimized for their
range of operation:
A snap action disc type bi-metal and contact asenbly
A bi-metal with a mechanical latch and separate spring loaded contact
A hot wire design with extremely fast switching time
All are individually calibrated in the factory to ensure safe, predictable performance
under a wide range of conditions.
B. magnetic circuit breakers 磁性过电流保护器
磁力过电流保护器的灵敏性更高，更可靠，更有效。它们有温度过电流保护器所
没有的优点。因为这种保护器是恒温的，所以不容易受外界温度的影响。这种过
电流保护器的设计理念是能给给客户提供一种自动的电路保护，开关功能以及电
路控制。
Magnetic circuit breakers provide highly precise, reliable and cost-effective solutions
to most design problems. They have the advantages of thermal breakers without their
disadvantages. Since the magnetic circuit breaker is considered to be temperature
stable, it is not appreciably affected by changes in ambient temperature. These circuit
breakers are designed to give our customers reliable automatic circuit protection
power switching and circuit control in a versatile , compact , cost-effective package.
磁力过电流保护器对微小电流的跳脱比温度过电流保护器更加精确。一般来说，
如果需求一种既精确又可靠的电路保护，那磁力过电流保护器就是最好的选择。
Magnetic circuit breakers offer a more precise trip time for delicate circuits than
thermal circuit breakers. Generally, wherever precise and reliable circuit protection is
required, a magnetic circuit breaker is specified.
磁力过电流保护器可以保护以下产品：
magnetic circuit breakers protect the following:
金属线 wiring
马达 motors
发电机和转换器 generators and transformers
固态电子系统 solid state systems
通信系统 telecommunications systems
微信息处理机 microprocessors
外围打印装置 peripheral and printing devices
工业自动化以及包装系统 industrial automation and packaging systems
机器工具 machine tools
医疗设备 medical and dental equipment
检测仪表 instrumentation
自动贩卖机 vending machines
过程控制系统 process control systems
电源供应 linear and switching power supplies
海事控制嵌板 marine control panels
办公设备 office machines
C 温度过电流保护器和磁力过电流保护器的特性
Characteristics of thermal and magnetic circuit breakers
温度过电流保护器 thermal
对温度敏感性 temperature sensitive
对电压无敏感性 not voltage sensitive
单极 single pole
间隔时间固定 fixed time delay
有Push or reset 功能或者是开关功能 push-to reset or switch function
仅限於电路保护功能 limited circuit functions
体积小 small package size
单价低廉 lower cost
磁力过电流保护器 magnetic
对温度不敏感 not temp sensitive
对电压有敏感性 voltage sensitive
单极或者多极 single or multi-pole
间隔时间不固定 various time delays
开关功能 switch function
各种不同的电路功能 variety of circuit funcitons
体积比温度过电流保护器大 larger package size
单价更高 higher cost
IV.应用 applications
电流保护这个领域要求操作特性必须完全符合精确的性能参数。您乘坐的飞机，
您居住的家园，您操作的电脑以及您使用的复印机等都有电路保护装置。
Circuit protection is an area where operating characteristics must meet precise
performance parameters. The aircraft you fly in, the house you live in, the computer
you operate and the photocopier you run all probably have circuit protection devices.
--电源供应：开关、线性的、ups、整流
--power supplies: switches, linear, UPS, rectifiers
--电源分流：电信、电脑、船只、剧院的灯盏、汽车栏杆
--power distribution: telecommunications ,computers, boat panes, theatrical lighting,
rail cars
－机械应用：复印机、测试检验设备、医疗设备、印刷机
--appliance protector: photocopiers, workstations, test&measurement equipment,
medical equipment , printers
－马达保护：HVAC 设备、潜水艇的泵、吸尘器、发电机装置
--motor protector: HVAC equipment, submersible pumps, vacuum cleaners,
generator sets.
－电池 battery charges
－国内机械：食品信息处理机、洗涤机、干燥机
--domestic appliances: food processors, washing machine, dryers
－军事装置：收音机、广播、地面支持设备、飞机
--military equipment: radios&broadcast, ground support, aerospace&airborne
－浪博保护 surge protectors
V．安全规则机构
为了保证产品和设备的安全运作，因此产生了这些安全机构，他们最基本的职责
包括：制定标准、对产品进行符合标准的评估，并且对符合标准的签发证书。这
些机构目的在於保护被电击、被机械致伤、火灾以及其他危险情况。同时，这种
保护行为也延伸到对电源供应部件以及和产品、设备中。
The need for ensuring consistently safe products and equipment prompted the creation
of safety agencies, whose prime responsibilities include writing standards, evaluation
of product to those standards, and issuing marks indicating compliance to the
applicable standards. These agencies are concerned with safety in forms such as
electrical shock, mechanical hazard, fire and other hazardous/ emergency conditions.
This concern is extended to the component power supply as well as end use
equipment or product.
由於每个国家制定的标准是不相容的，所以就不可能在全世界范围内使用同一种
保险丝。必须留意每个政府制定的标准是不同的。在设计的早期阶段就注意机构
的认证问题可以省掉很多麻烦。下面来看一下每个国家的认证标志。比较通用的
机构认证标志有：UL(美国)，CSA(加拿大)，VDE(德国),SEMKO（瑞士），BSI(英
国)，IEC(欧洲)
The incompatibility of standards between nations makes it impossible to use the same
fuse across the world in a given application. Attention needs to be given to the fact
that governing standards are different. Observation of this fact in the early design
stage will save trouble and confusion during the agency approval process. Look to
each nation’s marking s to ensure compliance. Some popular national agencies
include: UL(United nations), CSA(Canada), VDE(Germany), SEMKO(Sweden)，
BSI(United Kingdom), IEC(Europe)

美堂

鬼长鬼长的，字又小

一个白痴

学习了，谢谢楼主，，，

加糖的咖啡

介绍的挺详细的，要是能再多点资料就好了