Motor control centre advice

An up to date specification of a motor control centre or switchgear is very important for your projects.

Modifications, claims for extra work and delays in delivery, need to be avoided.

When you are not in the possession of suitable specifications and drawings Uil Advisors can provide these.

Specifications detailing a motor control centre or switchgear can be downloaded immediately from our shop. Instead of repeating generic information in each and every specification, our specifications are split-up in multiple individual specifications. By doing so, we have ensured that our specifications are to the point and easily accessible.

For the design of the assembly, the following individual specifications and data sheet to be used:

  • The specification of the motor control centre or switchgear describing specific requirements for the MCC
  • The electrical & instrumentation panel specification describing all generic requirements typical for E&I panels
  • The general information and requirements specifications describing the generic design requirements for all equipment and installations
  • The data sheet for the assembly

 
Other documents to support the specifications can be found in the chapter ‘Referenced Documents’.

Motor Control Centre Definition

The motor control centre, or MCC, is a structure that consists out of one or multiple enclosed sections that share a common power driver or multiple common power drivers. The motor control centre assembly typically contains multiple motor control units and feeder units. The assembly often includes an integrated motor management system, which interfaces with the overall Safeguarding System (SGS), Distributed Control System (DCS) and Unit Control Panels (UCP). The motor control centre is typically used for low voltage, three-phase alternating current motors and feeders. The voltage typically ranges from 400/230V.

Motor Control Centre Layout

As stated in the motor control center definition, the MCC is built up in a modular way. The assembly can be part of a single or multiple incoming power supply system, like:

  • Transformer(s)
  • Diesel engine driven generator set(s)
  • Gas engine driven generator set(s)
  • Emergency diesel engine driven generator set(s)
  • Temporary diesel engine driven generator set(s)

 A motor control centre can consist out of the following modular sections:

  • Future and / or spare, space withdrawable motor and/or feeder units
  • Panels containing withdrawable motor and/or feeder units
  • Control section(s) combined with (manual) synchronization equipment
  • Couple breaker(s) for connection with other MCC’s or parts of the same MCC
  • Permanent “temporary supply” connection(s) to the motor control centre
  • Low voltage switchgear panel(s) for each generator set
  • Low voltage switchgear panel(s) for each step down transformer
  • Low-voltage switchgear sections house at least the following parts:
    • For each low voltage switchgear panel
    • Generator main circuit breaker
    • Synchro check relay
    • Load sharing unit, including interface with generator driver control panel
    • Auto synchronizer
    • Voltage transformers
    • Current transformers
    • Display unit
    • PLC for LVS control
    • Control and auxiliary equipment
  • For the MCC control panel
    • All auxiliary equipment required for interface with safeguarding system
    • Control and auxiliary equipment
    • Complete motor management system
    • PLC’s for each switchgear
    • Synchronizing unit (manual)
    • Synchro scope
    • Indicators synchronization
  • For each MCC couple breaker panel
    • Couple breaker
    • Current transformers
    • Display unit
    • Volts meter and selector switch
    • Control and auxiliary equipment
  • For the temporary incoming supply panel
    • Generator circuit breaker
    • Current transformers
    • Volts meter and selector switch
    • Ammeter selector switch
    • Control and auxiliary equipment
  • For the MCC motor management system
    • Complete motor management system with interface PLC
    • Control and auxiliary equipment
    • One computer containing all applicable software and firmware

Motor control centre specification advantages

The biggest advantage of the Uil Advisors specification is that the complete assembly has been optimized in both size and functionality with withdrawable motor and feeder units. The compartments needed are designed in such a way, that they are fit for purpose, executed with proven equipment (like ABB, Eaton, Siemens, Woodward and others), suitable to split up in sections for transport and easy to connect field cabling in separate cable compartments. Also, the specification is optimized for maximum space efficiency in height, width and depth. Another great advantage of our motor control centre design is that the apparatus is easy to install. Finally, our motor control centre is optimized for low-maintenance, because of its modular design. Because of this, durability and cost-efficiency are maximized and the installation is suitable to be modified with new drawer units or complete sections. All these features add up to a switchgear that is perfect in both its form and functionality.

Why would you buy Uil Advisors motor control centre designs?

The motor control centre specifications provided in are highly detailed. One of the prime advantages of our specifications is that they don’t simply refer to standards or vendor standard. A detailed description of interfaces with several other parts of the complete installation is also explicitly described. The motor control centre specification refers to multiple reference specifications, which are available in the Uil Advisors shop as well. Together with these reference specifications, our MCC documentation provides clear guidelines to which vendor/manufacturer has to comply.

The problem with most specifications is that they are far too generic, often resulting in problems and therefore high(er) costs during the project execution. To prevent this, Uil Advisors’ motor control centre documentation offers a modular build-up, resulting in a completely detailed and customized project design and execution.

Size, layout, manufacturer

Our design focuses on maximum available amount of drawers in a cost efficient way. Future drawers or complete sections can be added at a later stage. The MCC modular documentation provides options for various options. Vendors like Siemens, ABB, Eaton and custom build panel manufacturers can then optimize their design according your requirements. This makes it possible to customize the motor control centre design to your preferred size and layout, according to applicable laws and regulations (like NEN-EN-IEC 61439 and 60439). Another advantage of this set-up is that the MCC in your project can be fully adjusted to the location requisite requirements or your project. The material choice for your motor control centre can be adjusted as well, in accordance with your industry requirements.

Protection

As with any other project, your motor control centre will have to be built according to industry standards. One of the important security measures for an MCC is ingress protection. The motor control centre specification focuses on ingress protection varying between IP41 and IP55. In order to protect circuits from being overloaded and short circuit, (motor operated) circuit breakers, fuses, auxiliary circuit breakers can be used. Depending on the make of panels you desire, coherent equipment will have to be used.

Standards, Laws and Regulations

In order to comply with current laws and regulations, the motor control centre specifications are based upon the requirements as per NEN-EN-IEC 60439 or NEN-EN-IEC 61439. This way, you as our customer are assured to be in complete compliance with current standards.

Our motor control centre designs focus on full functionality by describing every part of the project in detail. This high level of details enable you to specify an entirely customized project. Our MCC documentation refers to International and European standards and laws, For other continents, you will have to adjust the applicable references.

Operability

The motor control centre specification clearly describes safety, user-friendly and low-maintenance requirements. Operation of the individual units and sections can take place in various ways. Various ways to operate the units have been specified like local operation on the MCC itself, with a possibility to switch to remote control in field or operated by means of an operator station, unit control panel or DCS system and safeguarded by means of a dedicated safeguarding system.

Referenced specifications

In order to be able to provide complete information for the motor control centre design, reference specifications and drawings are detailed below. This documents can also be ordered in the shop. The reference specifications that apply to the motor control centre (PROJ-EL-SP-002) are:

  • PROJ-GEN-SP-001

o    General information and requirements

  • PROJ-EI-SP-001

o    Electrical & instrumentation panels

  • PROJ-GEN-LI-010

o    Applicable laws, regulations, codes, standards and authorities

  • STD-EI-LI-MCC CONTR

o    MCC control schedule

  • PROJ-EI-LI-NONPID

o    Non P&ID related I/O

  • STD-EL-DS-MCC

o    Motor control centre

o    Main emergency distribution panel

  • STD-EL-LI-LV LOAD

o    Load schedule

  • FAT-EI-CHK-NEN1010-6

o    Inspection test reports

  • PROJ-EI-SP-003

o    General drawing & drafting specification

Apart from the above mentioned reference specifications, a set of reference drawings is important to complete the motor control centre design. Typical referenced drawings are described below:

  • PROJ-EL-DR-004

o    Key one line diagram

  • PROJ-EL-DR-010 :      

o    Block diagram MCC control section

o    MCC arrangement

o    Typical MCC block diagram motor starter type, direct on line, <18kW

o    Typical MCC block diagram motor starter type, two (or more speeds)

o    Typical MCC block diagram starter type >18kW

o    Typical MCC block diagram feeder type <63A

o    Typical MCC schematic diagram starter type <18kW

o    Typical MCC connection diagram starter type <18kW

o    Typical MCC schematic diagram starter type >18kW

o    Typical MCC connection diagram starter type >18kW

o    Typical MCC schematic diagram starter type two (or more speeds)

o    Typical MCC connection diagram starter type two (or more speeds)

o    Typical MCC schematic diagram feeder type <63A

o    Typical MCC connection diagram feeder type <63A

  • PROJ-EL-DR-024

o    Power layout MCC location

The advantage of providing the above described documents to the Vendor as part of tender documents or requisition is provide your specific project requirements and interfaces with the field.

 The motor control centre specification (PROJ-EL-SP-002) also lists all the required reference specifications. The list included in this specification shows you exactly which part of the design can be found in which reference document. This way, it is possible for you to see why you need a supplementary specification upon downloading the motor control centre specification.

 The English word motor control centre is used in the specification and this can easily be replaced by motor control center.

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