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Motor control

Power distribution systems used in large commercial and industrial applications can be complex. Power may be distributed through switchgear, switchboards, transformers, and panelboards. Power distributed throughout a commercial or industrial application is used for a variety of applications such as heating, cooling, lighting, and motor-driven machinery.

Basics of Motor Control Centers - SIEMENS (on photo: New Motor Control Center and power distribution board up to 7000 amperes)
Basics of Motor Control Centers – SIEMENS (on photo: New Motor Control Center and power distribution board up to 7000 amperes)

Basic Motor Control

Wherever motors are used, they must be controlled.

Basic motor control
Basic motor control

In Basics of Control Components you learned how various control products are used to control the operation of motors.

The most basic type of AC motor control, for example, involves turning the motor on and off. This is often accomplished using a motor starter made up of a contactor and an overload relay.

The contactor’s contacts are closed to start the motor and opened to stop the motor. This is accomplished electromechanically using start and stop pushbuttons or other pilot devices wired to control the contactor.

The overload relay protects the motor by disconnecting power to the motor when an overload condition exists. Although the overload relay provides protection from overloads, it does not provide short-circuit protection for the wiring supplying power to the motor. For this reason, a circuit breaker or fuses are also used.

Typically one motor starter controls one motor. When only a few geographically dispersed AC motors are used, the circuit protection and control components may be located in a panel near the motor.

Motor Control Centers (MCC)

In many commercial and industrial applications, quite a few electric motors are required, and it is often desirable to control some or all of the motors from a central location. The apparatus designed for this function is the motor control center (MCC).

Motor control centers are simply physical groupings of combination starters in one assembly.

A combination starter is a single enclosure containing the motor starter, fuses or circuit breaker, and a device for disconnecting power.

Other devices associated with the motor, such as pushbuttons and indicator lights may also be included.

Title:Basics of Motor Control Centers – SIEMENS
Size:4.3 MB
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Basics of Motor Control Centers - SIEMENS
Basics of Motor Control Centers – SIEMENS

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  1. Mohammed Abid
    Jul 25, 2018

    Very useful article. Thanks a lot.

    What I understood is that the only purpose of the MCC is to group all the motor starters together in one place to reduce the cost of using multiple cables for each motor starter and that, in the MCC, each box has the starter and protection devices for the motor.

  2. deepika
    Feb 13, 2018

    This is a very useful article to understand the basics of MCC. Thanks for uploading

  3. Jon
    Nov 29, 2017

    Hi kindly can I have the link to download this article and thanks

    May 24, 2017


  5. Wilman Altamar de horta
    Apr 02, 2017

    Hola cómo están. Muy buena la información, me gustaría que los PDF se pudieran descargar en español.

  6. Ahammad Kabir
    Mar 29, 2017

    This article is excellent. Thank you Evan!

  7. Abu Haneefah
    Dec 22, 2016

    Tanks for the article. It’s a good one. However please I need you to send to me a student project on the design and construction of a 2KVA inverter with a pure sinewave output.

  8. wajid hussain
    Dec 22, 2016

    it is very useful for me

  9. Riyas Rasheed
    Oct 25, 2016

    Thanks for your great work.

  10. Angel
    Aug 03, 2016

    Hello, can you guys give us a aproximate cost for a motor control center for a water pumping station?

    Thank you,

  11. Engr. Allen Vunobolki
    Jul 24, 2015

    Hi. Could you please send me the 4.3MB Basics of motor control centres.

  12. matt
    Jul 02, 2015

    hi, just wondering, for panel schamtic design. should the layout of the schamtic be power section, control wiring section and then a BMS section. or should power supplies and control wiring be shown on the same page ?

  13. mohammad alqasem
    Nov 14, 2013

    Thank you , its really helpfull

  14. RichDad
    Aug 08, 2013

    please can you forward me the 4.3 MB Basics of Motor Control Centers

  15. mpriya
    Feb 28, 2013

    Hi Can you please forward me the 4.3 MB Basics of Motor Control Centers ,because I am been blocked from our administrator.

    Thank you

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