Danfoss inverters for application brackish water

Application: Brackish water - 3 APP 2,2 equiped with Danfoss inverters for flexible use at universety. Place of installation: UK


Selecting of a frequency converter for variable speed drives requires a lot of experience. If the experience is not available, it is often useful to visit either a reference plant with similar applications, or exhibitions or trade shows.


Checklist

The following is a brief checklist of points that should be considered:

  1. Details of the machine to be controlled
  2. Environmental details
  3. Mains
  4. Maintenance, operation, personnel
  5. Financial criteria
  6. Protective measures for operators/converter/motor
  7. Standards/regulations
  8. Environmental considerations
  9. Also important…

VLT Drives Applications (VIDEOS)

Some of the interesting applications done with Danfoss VLT drives:

  1. VLT drives in large desalination plant
  2. VLT drives control cooling tower fans
  3. VLT control optimizes spindle speed in Indian textile factory
  4. VLT frequency converters drive bagage handling system
  5. VLT Drives Save 78% Energy in Chester Zoo

1. Details of the machine to be controlled

  1. Required plant/machine characteristics
  2. Torque characteristics, stalling torque, acceleration torque
  3. Speed control range, cooling
  4. Power consumption of the converter and the motor
  5. Operating quadrants
  6. Slip compensation (dynamic)
  7. Required ramp-up and ramp-down times
  8. Required braking times, brake operating time
  9. Direct drives, gears, transmission components, moment of mass inertia
  10. Synchronisation with other drives
  11. Operating time, controls
  12. Computer linkage, interfaces, visualisation
  13. Design and protection type
  14. Possibility of integrating decentral intelligence in the frequency converter

Go up to the Checklist ↑


2. Environmental details

  1. Installation height, ambient temperature
  2. Cooling requirements, cooling options
  3. Climatic conditions, such as humidity, water, dirt, dustgas-es
  4. Special regulations, e.g. for mining, the chemical industrythe ship building industry, food technology
  5. Acoustic noise

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3. Mains

  1. Mains voltage, voltage fluctuations
  2. Mains performance
  3. Mains frequency fluctuations
  4. Mains interference
  5. Short-circuit and overvoltage protection
  6. Mains drop-out

Go up to the Checklist ↑


4. Maintenance, operation, personnel

  1. Training and instruction of operators
  2. Maintenance
  3. Spare parts/spare units

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5. Financial criteria

  1. Purchase costs (components)
  2. Space requirement, integrated installation, design
  3. Installation costs
  4. Commissioning of the system
  5. Set-up costs
  6. Operating costs
  7. Efficiency of the system (frequency converter and machine)
  8. Reactive power requirement and compensation for harmonic loads
  9. Product lifetime

Go up to the Checklist ↑


6. Protective measures for operators/converter/motor

  1. Galvanic isolation in accordance with PELV
  2. Phase drop-out
  3. Switching at the converter output
  4. Earth and short-circuit protection
  5. Motor coils to reduce voltage rise times
  6. Electronic thermal monitoring and connection of thermistors

Go up to the Checklist ↑


7. Standards/regulations

  1. National DIN, BS, UL, CSA, VDE, European EN
  2.  International IEC, CE, etc.

Go up to the Checklist ↑


8. Environmental considerations

  1. Ability to recycle the product
  2. Manufacturing practice
  3. Energy saving factors

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Also important…

Using this checklist a frequency converter can be selected which covers most of the items as standard, but you should also double check whether:

  • The converter has mains or intermediate circuit chokes in order to greatly reduce mains interference
  • A RFI filter for class A or B is standard or has to be purchased separately
  • Motor derating is required if a frequency converter is used
  • The converter itself is protected against earth and short-circuit
  • The converter reacts adequately in a fault situation.

Go up to the Checklist ↑

VLT Drives Applications (VIDEOS)

1. VLT drives in large desalination plant

Cant see this video? Click here to watch it on Youtube.

Go up to the Applications ↑


2. VLT drives control cooling tower fans

Cant see this video? Click here to watch it on Youtube.

Go up to the Applications ↑


3. VLT control optimizes spindle speed in Indian textile factory

Cant see this video? Click here to watch it on Youtube.

Go up to the Applications ↑


4. LT frequency converters drive bagage handling system

Cant see this video? Click here to watch it on Youtube.

Go up to the Applications ↑


5. LT Drives Save 78% Energy in Chester Zoo

Cant see this video? Click here to watch it on Youtube.

Go up to the Applications ↑

Resource: Fact Worth Knowing About Frequency Converters – Danfoss


author-pic

Edvard - Electrical engineer, programmer and founder of EEP. Highly specialized for design of LV high power busbar trunking (<6300A) in power substations, buildings and industry fascilities. Designing of LV/MV switchgears. Professional in AutoCAD programming and web-design. Present on Google+.



5 Comments


  1. Dorin Pestereanu
    Jun 17, 2014

    Very , very useful ; I’ve worked with variable speed drives, so I know the subject ; Many thanks for your effort !

  2. [...] a Frequency Converter (photo by Yaconto LLC.)Two types of influenceWhen a motor is connected to a frequency converter it must be kept at the correct temperature, and this is subject to two types of influence:If the [...]


  3. tarekdia
    Dec 23, 2012

    why not make a downloadable version of the article in the form of pdf file so it can be read later
    thanks for the effort


    • Edvard
      Dec 23, 2012

      Hi Tarekdia,

      You can make PDF of any technical article using link ‘Get PDF’ at the top of article, below title on the right.

      You can optimize your PDF, set font size and remove images as well.

  4. [...] (on photo cabinet with Danfoss FC302 frequency converters)IntroductionSince the late 1960’s, frequency converters have undergone extremely rapid changes, largely as a result of the development of microprocessor [...]

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