Preview

Contactors: Relay and Coil

Good Essays
Open Document
Open Document
1021 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
Contactors: Relay and Coil
Contactors & Relays
Contactors and relays are devices that open and close a set or sets of electric contacts by the action of a solenoid coil. A contactor is used to control an electric load in a control system. Contactors make or break a set of contacts that controls the voltage applied to some load in cooling systems. A contactor consists of a coil that opens and closes a set of contacts due to the magnetic attraction created by the coil when it is energized. Magnetic starters are also used to start and stop large loads in cooling systems. The major difference between magnetic starters and contactors is that the magnetic starter houses its own overload. Different manufactures design contactors in different ways, but all accomplish the same purpose which is opening and closing a set of contacts. The armature of a contactor is the portion that moves. The sliding armature mounts between two slots in the frame of the contactors and moves up and down in these slots. The swinging armature is mounted on a pivot or hinge and moves up and down in a swinging motion.
The armature of a contactor is connected by a mechanical linkage to a set of contacts that causes a completed circuit when the armature is pulled into the magnetic field produced by the coil. The coil characteristics depend on the type of wire and the manner in which it is wound. Coils are designed to operated on 24volts, 120 volts, 208/240 volts, and 480 volts. Contactors are rated by the ampere draw they can carry. There are two types of loads that contactors can control: and inductive load which has a higher ampere draw on startup than while running; and a resistive load which has a constant ampere draw such as a resistance heater. Contacts are made of silver and cadmium (is a chemical element with the symbol Cd and atomic number 48. The soft, bluish-white metal is chemically similar to the two other metals in group 12, zinc and mercury), which resists sticking. The contacts are

You May Also Find These Documents Helpful

  • Satisfactory Essays

    This had a max of eight different telephone lines. In 1892 the first set of commercial installation of automatic switching equipment using the step by step mechanism was made at La Porte in Indiana. Various calling devices were used for a number of years. Among these were lever operated pre-set devices, key sets of several types, and dials with holes in which a peg could be inserted to act as a stop for an arm which was pulled around and allowed to restore. In all the early systems, regardless of the device used, the signals generated at the calling station directly controlled the selectors. The rotary dial works on a pulse based system. The frequency of pulses is determined by the number on the dial which the caller selects. Using the manually turn dialer to a fixed angel where the finger releases it before the number arrives while spinning. While this occurs these causes the dial spin to return to the starting position.Inside the body of the phone a centrifugal governor ensures that the dial’s rotation is moderated to a constant rate, with a shaft on the governor turning a cam that opens and closes a switch contact. If the contact is open, the line’s current is stopped from flowing, thereby creating a dial pulse, while when closed, there is a constant flow of…

    • 606 Words
    • 3 Pages
    Satisfactory Essays
  • Better Essays

    Yoke- It is the outer frame of a DC and it is made up of cast iron or steel. It carries the magnetic flux produced by field…

    • 1562 Words
    • 7 Pages
    Better Essays
  • Satisfactory Essays

    Copper wire is used to power appliances and other devices so it has a high capacity for transmitting electricity.…

    • 195 Words
    • 2 Pages
    Satisfactory Essays
  • Good Essays

    The contacts conduct electricity to the copper ring. The copper ring rotates rapidly but does not…

    • 272 Words
    • 2 Pages
    Good Essays
  • Good Essays

    Coils can also be used as 3-D designs on the outside of pots or as handles or as…

    • 379 Words
    • 1 Page
    Good Essays
  • Satisfactory Essays

    ET2750

    • 545 Words
    • 2 Pages

    . The input contacts in a relay logic diagram represent actual components and contacts present in the control system, while the input instructions in the PLC ladder logiconly represent data values stored in the PLC.…

    • 545 Words
    • 2 Pages
    Satisfactory Essays
  • Good Essays

    -opposite of a generator (even in diagrams; inner magnets’ poles are opposite. The magnet rotates because each time it is either repelled or attracted by the permanent magnet and has to move that way.)…

    • 4047 Words
    • 17 Pages
    Good Essays
  • Good Essays

    A.) Permanent magnets, High tension coil, Mechanical or electronic switching device, Condenser, High tension spark plug wire, Spark plug…

    • 565 Words
    • 3 Pages
    Good Essays
  • Satisfactory Essays

    CU, Inc. (CUI) produces copper contacts that it uses in switches and relays. CUI needs to determine the…

    • 278 Words
    • 2 Pages
    Satisfactory Essays
  • Powerful Essays

    Motor and Controls

    • 5398 Words
    • 22 Pages

    All motors must have a control device to start and stop the motor called a “motor controller”. Motor Controller A motor controller is the actual device that energizes and de-energizes the circuit to the motor so that it can start and stop. • Motor controllers may include some or all of the following motor control functions: S S starting, stopping, over-current protection, overload protection, reversing, speed changing, jogging, plugging, sequence control, and pilot light indication. Controllers range from simple to complex and can provide control for one motor, groups of motors, or auxiliary equipment such as brakes, clutches, solenoids, heaters, or other signals.…

    • 5398 Words
    • 22 Pages
    Powerful Essays
  • Good Essays

    relay

    • 2530 Words
    • 11 Pages

    A type of relay that can handle the high power required to directly control an electric motor or other loads is called a contactor. Solid-state relays control power circuits with no moving parts, instead using a semiconductor device to perform switching. Relays with calibrated operating characteristics and sometimes multiple operating coils are used to protect electrical circuits from overload or faults; in modern electric power systems these functions are performed by digital instruments still called "protective relays".…

    • 2530 Words
    • 11 Pages
    Good Essays
  • Better Essays

    Arc Welding

    • 1103 Words
    • 5 Pages

    Electrode This is where the current passes from the welder to the work piece. There are two types: 1) Contact/consumable 2) Non Contact…

    • 1103 Words
    • 5 Pages
    Better Essays
  • Good Essays

    Introduction to Plc

    • 2873 Words
    • 12 Pages

    Modern control systems still include relays, but these are rarely used for logic. A relay is a simple device that uses a magnetic field to control a switch, as pictured in . When a voltage is applied to the input coil, the resulting current creates a magnetic field. The magnetic field pulls a metal switch (or reed) towards it and the contacts touch, closing the switch. The contact that closes when the coil is energized is called normally open. The normally closed contacts touch…

    • 2873 Words
    • 12 Pages
    Good Essays
  • Good Essays

    ‘COST’ represents a sacrifice of values, a foregoing or a release of something of value. It is the price of economic resources used as a result of producing or doing the thing costed. It is the amount of expenditure incurred on a given thing.…

    • 612 Words
    • 3 Pages
    Good Essays
  • Good Essays

    Magnet Research Papers

    • 663 Words
    • 3 Pages

    As you might know, magnets can be found it many places and help a lot and can be used in various ways for example the Earth is a big magnet. This is how compasses work. The Earth’s magnetic field is called the magnetosphere. It can also react with things in space. When energy from the sun interacts with the magnetosphere, the northern and southern lights are formed. Magnets can also be found in motors, electric generators, and also transistors which are . Motors contain cube coil that act like electromagnets.…

    • 663 Words
    • 3 Pages
    Good Essays