EXIN EXIN-CDCP Online Practice Questions and Exam Preparation

EXIN EXIN-CDCP Online Questions & Answers

• Question 1:

  What is the recommended location for the Isolation Transformer in relation to the ICT-Equipment location?

  A. The isolation transformer should be as close as possible to the ICT equipment but taking into account potential EMF.
  B. The isolation transformer should be as far away as possible to the ICT equipment to avoid potential EMF.
  C. The isolation transformer has to be installed within the power entry point of the building due to electrical code (regulation) requirements.
  D. The isolation transformer should be installed within the rack in which the ICT equipment has been installed.
  A. The isolation transformer should be as close as possible to the ICT equipment but taking into account potential EMF.

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  Explanation

  According to the EPI Data Centre Training Framework, an isolation transformer is a device that transfers electrical power from one circuit to another without changing the voltage or frequency, but providing galvanic isolation. Galvanic isolation means that there is no direct electrical connection between the input and output circuits, which can prevent ground loops, reduce noise, and improve safety. An isolation transformer can also provide voltage stepdown or stepup, create a local ground-bonded neutral, reduce harmonic currents, and provide taps for abnormal mains voltage.

  The location of the isolation transformer in relation to the ICT equipment depends on the purpose and design of the transformer. In general, the isolation transformer should be as close as possible to the ICT equipment, but taking into account potential EMF. EMF is a form of electromagnetic interference (EMI) that can affect the performance and reliability of the ICT equipment. The closer the isolation transformer is to the ICT equipment, the shorter the cable length and the lower the voltage drop and power loss 4. However, the isolation transformer should also be far enough from the ICT equipment to avoid EMF, which can be reduced by using proper shielding, grounding, and spacing.

  The isolation transformer should not be installed as far away as possible to the ICT equipment, as option B suggests, because this would increase the cable length and the voltage drop and power loss. The isolation transformer does not have to be installed within the power entry point of the building, as

  option C suggests, because this is not a requirement of the electrical code or regulation, and it may not be optimal for the data centre power system. The isolation transformer should not be installed within the rack in which the ICT equipment has been installed, as option D suggests, because this would increase the heat load and the noise level in the rack, and it may not fit in the rack space.

  References:

  1: EPI Data Centre Training Framework, Module

  5: Power, Section 5.4.3: Isolation

  2: Guidelines for using isolation transformers in data center UPS systems - EEP1, Page 1

  3: The Role of Isolation Transformers in Data Center UPS Systems2, Page 2

  4: Data Center Transformer | Power Distribution - FGC Construction3, Page 1

  5: EPI Data Centre Training Framework, Module

  5: Power, Section 5.4.1: Electromagnetic Interference, Page 5-34 : Data centre transformers manufacturers - TMC Transformers4, Page

  1 : The Role of Isolation Transformers in Data Center UPS Systems2, Page 25

• Question 2:

  What is the primary reason to install a monitoring system in the data centre?

  A. To notice abnormalities early so that actions can be taken to avoid disasters
  B. To create a proper asset database
  C. To implement automated change management
  D. To be able to collect data for capacity planning
  A. To notice abnormalities early so that actions can be taken to avoid disasters

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  Explanation

  The primary reason to install a monitoring system in the data centre is to notice abnormalities early so that actions can be taken to avoid disasters, according to the CDCP Preparation Guide1 and various web sources 234. A monitoring system is a system that collects and analyzes data about the power, cooling, environmental, and security conditions in the data centre, and alerts the operators or managers about any issues or threats that may affect the performance, availability, or reliability of the data centre. A monitoring system can help to prevent or minimize the impact of disasters, such as power outages, fire, water damage, overheating, equipment failure, or cyberattacks, by providing timely and accurate information that enables fast and corrective action. A monitoring system can also help to improve the energy efficiency, capacity planning, and asset management of the data centre, by providing useful insights and trends that support informed decision making.

• Question 3:

  What are the four main components of a refrigeration circuit?

  A. Evaporation, membrane filter, monitor sensor, pressure valve
  B. Evaporator, compressor, condenser, expansion valve
  C. Condenser, expansion valve, buffer tank, de-icing unit
  D. Thermostat, monitoring interface, indoor unit, outdoor unit
  B. Evaporator, compressor, condenser, expansion valve

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  Explanation

  The four main components of a refrigeration circuit are the evaporator, the compressor, the condenser, and the expansion valve, according to the CDCP Preparation Guide and various web sources. A refrigeration circuit is a system that transfers heat from a low-temperature region to a high-temperature region, using a working fluid called refrigerant. The refrigeration circuit operates in a closed loop, where the refrigerant changes its state from liquid to vapor and back to liquid, while absorbing and releasing heat.

  The four main components of the refrigeration circuit perform the following functions:

  1. The evaporator is a heat exchanger that absorbs heat from the low-temperature region, such as the data centre room, and transfers it to the refrigerant. The refrigerant enters the evaporator as a low-pressure, low-temperature liquid, and leaves the evaporator as a low-pressure, low-temperature vapor.

  2. The compressor is a mechanical device that increases the pressure and temperature of the refrigerant vapor. The refrigerant enters the compressor as a low-pressure, low-temperature vapor, and leaves the compressor as a high-pressure, high-temperature vapor.

  3. The condenser is another heat exchanger that releases heat from the refrigerant to the high-temperature region, such as the outside air or water. The refrigerant enters the condenser as a high-pressure, high-temperature vapor, and leaves the condenser as a high-pressure, low-temperature liquid.

  4. The expansion valve is a device that reduces the pressure and temperature of the refrigerant liquid.

  The refrigerant enters the expansion valve as a high-pressure, low-temperature liquid, and leaves the expansion valve as a low-pressure, low-temperature liquid. The expansion valve also controls the flow of the refrigerant into the evaporator, depending on the cooling load.

• Question 4:

  The three elements of the fire triangle are,and. (Choose three.)

  A. Oxygen
  B. Earth
  C. Heat
  D. Water
  E. Fuel
  A. Oxygen
  C. Heat
  E. Fuel

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  Explanation

  The fire triangle is a simple model that illustrates the three elements that a fire needs to ignite and sustain: oxygen, heat, and fuel. Oxygen is the oxidizing agent that enables the combustion reaction, heat is the energy source that raises the temperature of the fuel to its ignition point, and fuel is the material that reacts with oxygen and releases heat and light. Removing any one of these elements can extinguish a fire. For example, water can reduce the heat and the oxygen, sand or soil can smother the fuel and the oxygen, and fire extinguishers can displace the oxygen or lower the temperature.

  References:

  66. EPI Data Centre Framework, Module 4: Fire Protection, page

  4. 1, 2, 3.

• Question 5:

  By what are magnetic fields of the type 'H' or 'B' created?

  A. Magnetic fields are created when an electric current flows; the greater the current, the stronger the magnetic field.
  B. Magnetic fields are created by the magnetic flux of the earth which varies per month.
  C. Magnetic fields are created by voltage; the greater the voltage, the stronger the magnetic field.
  D. Magnetic fields are created when there is a high level of common mode noise (CMN); the greater the common mode noise (CMN), the stronger the magnetic field.
  A. Magnetic fields are created when an electric current flows; the greater the current, the stronger the magnetic field.

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  Explanation

  According to the CDCP Preparation Guide1, magnetic fields of the type `H' or `B' are created when an electric current flows through a conductor, such as a wire or a coil. The magnetic field strength `H' is proportional to the current `I' and the number of turns `N' of the coil, and inversely proportional to the length

  `l' of the coil. The magnetic flux density `B' is proportional to the magnetic field strength `H' and the permeability `' of the medium in which the magnetic field exists. The greater the current, the stronger the magnetic field and the magnetic flux density. The relationship between `H', `B', `I', `N', `l', and `' can be expressed by the following equations:

  H = N I / l

  B =H

• Question 6:

  A heavy equipment cabinet must be moved across a data centre floor.

  What should be checked before the move?

  A. Only the cabinet's final electrical connection
  B. Only the width of the cabinet doors
  C. The floor's rolling-load capability and the planned travel path
  D. The color and finish of the floor panels
  C. The floor's rolling-load capability and the planned travel path

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  Explanation

  The route must support the load while the cabinet is moving, not only after it reaches its final position.

  Checking the travel path also identifies obstacles and weak areas before the move begins.

• Question 7:

  Which type of Humidifier is composed of water-filled canister containing electrodes?

  A. Infrared Humidifiers
  B. Water Canister Humidifier
  C. Steam Canister Humidifier
  D. Ultrasonic Humidifier
  C. Steam Canister Humidifier

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  Explanation

  A steam canister humidifier is a type of humidifier that uses electricity to heat water in a canister containing electrodes. The water conductivity and the water level determine the amount of current and steam production. The steam canister humidifier is also known as an electrode boiler humidifier or an electrode steam humidifier 123.

• Question 8:

  A team is routing power and data cabling through the same crowded pathway.

  Which design decision is most appropriate?

  A. Separate and organize the pathways to reduce interference and service risk
  B. Bundle every cable tightly to minimize visible space
  C. Route new cables across equipment service areas
  D. Remove cable labels so pathways appear less crowded
  A. Separate and organize the pathways to reduce interference and service risk

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  Explanation

  Organized separation reduces avoidable interaction between cable systems and makes future work safer and easier to control. Tight mixed bundles and unlabeled routes increase maintenance difficulty and the chance of accidental disruption.

• Question 9:

  A facility has several environmental sensors, but all are installed in one convenient location.

  What is the main weakness?

  A. The sensors will always report different units
  B. The readings may not represent conditions across the room
  C. The sensors will prevent equipment maintenance
  D. The monitoring system will stop recording alarms
  B. The readings may not represent conditions across the room

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  Explanation

  Conditions can vary by location, so a single cluster may hide hot, cold, or otherwise abnormal areas. Sensor placement should represent the spaces and risks being monitored.

• Question 10:

  Sprinkler heads used in computer rooms activate at what temperature?

  A. 57 degC (135 degF)
  B. 27 degC (81 degF)
  C. 70 C (158 degF)
  D. Only on direct contact with a flame
  A. 57 degC (135 degF)

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  Explanation

  Sprinkler heads used in computer rooms activate at 57 degC (135 degF),, which is the standard temperature rating for ordinary sprinklers. This is the temperature at which the heat-sensitive element of the sprinkler head, such as a glass bulb or a fusible link, breaks or melts, allowing water to flow from the sprinkler.

  Sprinkler heads are designed to activate only when exposed to a fire, not to ambient temperature fluctuations. Therefore, sprinkler heads should be installed at a sufficient distance from the heat sources, such as servers, racks, or ducts, to avoid accidental activation. Sprinkler heads should also be selected and installed in accordance with the relevant standards and codes, such as NFPA 13 and NFPA 75.