قريبا الموضوع الثالث ان شاء الله
قريبا الموضوع الثالث ان شاء الله
ما شاء الله مجهود رائع ومتميز
كم كنت محتاج الى هذا الجزء من الكهرباء بداية من معنى الفولت voltage
سأكون على متابعة معك باذن الله
جزاك الله خيرا
محمد بجد ماشاء الله عليك
وانا عارفة انت تعبت اد اية على ماوصلت للموضوع
وكمان على مانزلته بجد ربنا يبارك فيك
مشكووووووووووور اخي على هذا الموضوع الرائع ونتمنا ان تحضر لنا موضوع عن النضريات في الكهرباء مثل نضرية اوم ودوائر ثفنن ونورتن واكرر الشكر
مشكوررر على هذة الردود
ان الله فى عون العبد ما دام العبد فى عون اخيه .
بسم الله الرحمن الرحيم
سوف ابدا الان انشاء الله بوضع الجزء الثالث وهو
وسوف نتكلم فية عن الشوتش وانواعة وكيف يعمل وايضا الريلى ويضا السولنايد ( صمام يعمل بالمجلب المغناطيسى )
Control devices are used to "turn on" or "turn off" current flow in an electrical circuit. Control devices include a variety of switches, relays, and solenoids. Electronic control devices include capacitors, diodes, and transistors, but those will be discussed in another training module.
Control devices are needed to start, stop, or redirect current flow in an electrical circuit. Most switches require physical movement for operation while relays and solenoids are operated with electromagnetism.
RELAYSSingle Pole Single Throw (SPST)
Single Pole Double Throw (SPDT)
Multiple Pole Multiple Throw (MPMT or Gang Switch)
A switch is the most common circuit control device. Switches usually have two or more sets of contacts. Opening these contacts is called "break" or "open" the circuit, Closing the contacts is called "make" or "completing" the circuit.
Switches are described by the number of Poles and Throws they have. "Poles" refer to the number of input circuit terminals while "Throws" refer to the number of output circuit terminal. Switches are referred to as SPST (single-pole, single-throw), SPDT (single-pole, double-throw), or MPMT (multiple-pole, multiple-throw).
SINGLE POLE SINGLE THROW SPST)
The simplest type of switch is a "hinged pawl" or "knife blade" switch. It either "completes" (turn on) or "break" (turn off) the circuit in a single circuit. This switch has a single input pole and a single output throw.
SINGLE POLE DOUBLE THROW SPDT)
A single-pole input, double-throw output switch has one wire going it and two wires coming out. A Headlamp dimmer switch is a good example of a single-pole double-throw switch. The switch sends current to either the high-beams or low-beams of the headlight circuit.MULTIPLE POLE MULTIPLE THROW MPMT)
Multiple-Pole input, Multiple-Throw output switches, which are also known as "gang" switches, have movable contacts in wired in parallel. These switches move together to supply different sets of output contacts with current. An ignition switch is a good example of a multiple-pole multiple-throw switch. Each switch sends current from different source to different output circuits at the same time depending on position. The dotted line between the switches indicates they move together; one will not move without the other moving as well.
The momentary contact switch has a spring-loaded contact that keeps it from making the circuit except when pressure is applied to the button. This is a "normally open" type (shown below). A horn switch is a good example of a momentary contact switch. Push the horn button and the hold sounds; release the button and the horn stops.
A variation of this type is the normally closed (not shown) which works the opposite as described above. The spring holds the contacts closed except when the button is pressed. In other words the circuit is "ON" until the button is pushed to break the circuit.
A mercury switch is made of a sealed capsule that is partially filled with mercury. In one end of the capsule are two electrical contacts. As the switch is rotated (moved from true vertical) the mercury flows to the opposite end of the capsule with the contacts, completing the circuit. Mercury switches are often be used to detect motion, such as the one used in the engine compartment on the light. Other uses include fuel cut off for roll-overs, and some air bag sensor applications. Mercury is a hazardous waste and should be handled with care.
A temperature-sensitive switch, also known as a "bi-metallic" switch, usually contains a bimetal element that bends when heated to make contact completing a circuit or to break contact opening a circuit. In an engine coolant temperature switch, when the coolant reaches the temperature limit, the bimetal element bends causing the contacts in the switch to close. This completes the circuit and lights the warning indicator on the instrument panel.TIME DELAY SWITCH
The time delay switch contains a bimetal strip, contacts, and a heating element. The time delay switch is normally closed. As current flows through the switch, current flows through the heating element causing it to heat, which causes the bimetal strip to bend and open the contacts. As current continues to flows through the heating element, the bimetal strip is kept hot, keeping the switch contacts open. The amount of time delay before the contacts open is determined by the characteristics of the bimetal strip and the amount of heat produced by the heating element. When power to the switch is turned off, the heating element cools and the bimetal strip returns to the rest position and the contacts are closed. A common application for a time delay switch is the rear window defroster.
The flasher operates basically the same as the time delay switch; except when the contacts open, current stops flowing through the heating element. This causes the heating element and bimetal strip to cool. The bimetal strip returns to the rest position which closes the contacts, allowing current to flow through the contacts and heating element again. This cycle repeats over and over until power to the flasher is eliminated. Common uses for this type of switch are the turn signals or the four-way flasher (hazard lamps).
A relay is simply a remote-control switch, which uses a small amount of current to control a large amount of current. A typical relay has both a control circuit and a power circuit. Relay construction contains an iron core, electromagnetic coil, and an armature (moveable contact set). There are two types of relays: normally open (shown below) and normally closed (NOT shown). A Normally open (N.O.) relay has contacts that are "open" until the relay is energized while a normally closed (N.C.) relay has contacts that are "closed" until the relay is energized.
Current flows through the control coil, which is wrapped around an iron core. The iron core intensifies the magnetic field. The magnetic field attracts the upper contact arm and pulls it down, closing the contacts and allowing power from the power source to go to the load. When the coil is not energized, the contacts are open, and no power goes to the load. When the control circuit switch is closed, however, current flows to the relay and energizes the coil. The resulting magnetic field pulls the armature down, closing the contacts and allowing power to the load. Many relays are used for controlling high current in one circuit with low current in another circuit. An example would be a computer, which controls a relay, and the relay controls a higher current circuit.
SOLENOIDS - PULLING TYPE
A solenoid is an electromagnetic switch that converts current flow into mechanical movement. As current flows through the winding a magnetic field is created. The magnetic field will pull the moveable iron core into the center of the winding. This type of solenoid is called a "pulling" type solenoid, as the magnetic field pulls the moveable iron core into the coil. A common use for pulling solenoids are in the starting system. The starter solenoid engages the starter with the flywheel.
SOLENOIDS - PULLING TYPE OPERATION
As current flows through the winding a magnetic field is created. These magnetic lines of force want to be as small as possible. If an iron core is placed near the coil that has current flowing through it, the magnetic field will stretch out like a rubber band, reaching out and pulling the iron bar into the center of the coil.SOLENOIDS - PUSH/PULL TYPE
In a "push-pull" type solenoid, a permanent magnet is used for the core. Since "like" magnetic charges repel and "unlike" magnetic charges attract, by changing the direction of current flow through the coil, the core is either "pulled in" or "pushed out." A common use for this type of solenoid is on electric door locks.
اى استفسار ان شاء الله انا موجود
ان شاء الله قريبا الموضوع الرابع
الموضوع الرابع عن ( حماية الدوائر الكهربية فى السيارات )
يارب يعجبكم .
Circuit protection devices are used to protect wires and connectors from being damaged by excess current flow caused by either an over current or short-circuit. Excess current causes excess heat, which causes circuit protection to "open circuit".
CIRCUIT PROTECTION DEVICES
Fuses, fuse elements, fusible links, and circuit breakers are used as circuit protection devices. Circuit protection devices are available in a variety of types, shapes, and specific current ratings.
A fuse is the most common protection device. A fuse is placed in an electrical circuit, so that when current flow exceeds the rating of the fuse it "blows" or "blows out". The element in the fuse melts, opening the circuit and preventing other components of the circuit from being damaged by the overcurrent. The size of the metal fuse element determines its rating. Remember, excessive current causes excess heat, and it's the heat and not the current that causes the circuit protector to open. Once a fuse "blows" it must be replaced with a new one.
Fuses are located throughout the entire vehicle. Common locations include the engine compartment, behind the left or right kick panels, or under the dash. Fuses are usually grouped together and are often mixed in with other components like relays, circuit breakers, and fuse elements.
FUSE BLOCK COVERS
Fuse / relay block covers usually label the location and position of each fuse, relay, and fuse element contained within.FUSE TYPES
Fuses are classified into basic categories: blade type fuses or cartridge type fuses. Several variations of each are used.
COMMON FUSE TYPES
The blade fuse and fuse element are by far the most commonly used today. Three different types of blade fuses exist; The Maxi Fuse, The Standard Auto fuse, and the Mini fuse. The fuse element has replaced the fusible link and will be explained later.
The blade type fuse is a compact design with a metal element and transparent insulating housing which is color-coded for each current rating. (Standard Auto shown below; however construction of both the mini and maxi fuses are the same.)
FUSE AMPERAGE COLOR RATING
Fuse amperage color ratings for both the mini and standard ATO fuses are identical. However, the amperage color ratings of maxi fuses use a different color scheme.
Color Ratings For STANDARD and MINI Fuses
Fuse Amp Rating
Color Ratings For MAXI Fuses
Fuse Amp Rating
OLDER TYPE FUSES
Many older vehicles, both foreign and domestic, use glass or ceramic fuse cartridges that were either color coded or stamped on case for current ratings. Glass fuses were used on older domestic vehicles while the ceramic were used on most older European vehicles. Ceramic fuses used an amperage color rating system while glass fuses have the amperage ratings stamped into one of the metal end caps.
FUSIBLE LINKS AND FUSE ELEMENTS
Fusible links are divided into two categories: the fuse element cartridge and the fusible link. The construction and function of fusible links and fuse elements are similar to that of a fuse. The main difference is that the fusible link and fuse element are used to protect higher amperage electrical circuits, generally circuits 30 amps or more. As with fuses, once a fusible link or fuse element blows out, it must be replaced with a new one.
FUSE ELEMENT CARTRIDGE
Fuse elements, a cartridge type fusible link, are also known as a Pacific fuses. The element has the terminal and fusing portion as a unit. Fuse elements have replaced fusible links for the most part. The housing is color coded for each current rating. Although fuse elements are available in two physical sizes and are either plug in or bolt on design, the plug-in type is the most popular.
FUSE ELEMENT CARTRIDGE CONSTRUCTION
Construction of the fuse element is quite simple. A colored plastic housing contains the fusing portion element which can be viewed through a clear top. Fuse ratings are also stamped on the case.
FUSE ELEMENT COLOR IDENTIFICATION
Fuse amperage color ratings are shown below. The fusing portion of the fuse element is visible through a clear window. The amperage ratings are also listed on the fuse element.
Fuse Element Color Ratings - Pacific
Fusible elements are often located near the battery by themselves.
Fusible elements can also be located in relay / fuse boxes in the engine compartment.FUSIBLE LINKS
Fusible links are short pieces of a smaller diameter wire designed to melt during an over current condition. A fusible link is usually four (4) wire sizes smaller than the circuit that it is protecting. The insulation of a fusible link is a special nonflammable material. This allows the wire to melt, but the insulation to remain intact for safety. Some fusible links have a tag at one end that indicates its rating. Like fuses, fusible links must be replaced after they have "blown" or melted opened. Many manufacturers have replaced fusible links with fuse elements or maxi fuses.
Circuit breakers are used in place of fuses for the protection of complicated power circuits such as the power windows, sunroofs and heater circuits. Three types of circuit breakers exists: The manual reset type - mechanical, the automatic resetting type - mechanical, and the automatically reset solid state type - PTC. Circuit breakers are usually located in relay/fuse boxes; however, some components like power window motors have circuit breakers built in.
CIRCUIT BREAKER CONSTRUCTION MANUAL TYPE
A circuit breaker basically consists of a bimetal strip connected to two terminals and to a contact in between. Manual circuit breaker when tripped (current flow beyond its rating) will open and must be reset manually. These manual circuit breakers are called "non-cycling" circuit breakers.
CIRCUIT BREAKER OPERATION MANUAL TYPE
The circuit breaker contains a metal strip made of two different metals bonded together called a bimetal strip. This strip is in the shape of a disc and is concaved downward. When heat from the excessive current is higher than the circuit breaker current rating, the two metals change shape unevenly. The strip bends or warps upwards and the contacts open to stop current flow. The circuit breaker can be reset after it is tripped.
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