CDCS試験問題集を使って一日でEPI Data Centre試験合格目指す（最新の60解答)
CDCS試験正確な問題集、学習ノートと理論
EXIN CDCS 認定試験の出題範囲：
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質問 # 25
From the options indicated, what is the correct starting point for the raised floor installation?
- A. Point D
- B. Point B
- C. Point A
- D. Point C
正解：B
解説：
When installing a raised floor, the best starting point is typically from the farthest corner away from the entrance, in this case, Point B. This method allows for the floor installation to progress towards the entrance, ensuring that workers can avoid walking over the newly installed tiles, thus minimizing the risk of damage and maintaining cleanliness during installation.
Detailed Explanation:
Starting at the farthest corner (Point B) and working towards the entrance (Point A) is a standard practice in raised floor installation. This approach ensures that installers do not walk over freshly laid tiles, which could lead to shifting or misalignment. Additionally, it allows for more controlled placement and alignment, as well as convenient egress when installation is complete.
EPI Data Center Specialist References:
EPI guidelines for raised floor installation emphasize beginning at the farthest point from the entrance and working back towards it, which aligns with industry best practices for efficiency and quality assurance. This method reduces potential damage and supports precise alignment across the floor area.
質問 # 26
A data center scores Rated-3 in mechanical, Rated-4 in electrical, and Rated-2 in architectural.
What is the overall Rating of this data center when the Rating is based on the ANSI/TIA-942?
- A. Rated-4 since electrical is more important than mechanical and architectural
- B. Rated-4 since that is the highest rating received
- C. Rated-2 since that is the lowest rating received
- D. Depends on the Rating scored in telecommunications
正解：C
解説：
According to ANSI/TIA-942 standards, the overall data center rating is determined by the lowest rating among all evaluated categories. Therefore, if a data center is rated 2 in architectural, despite being rated higher in mechanical and electrical, the overall rating is Rated-2. This approach ensures that all aspects meet a minimum standard and prevents a higher rating if any critical area does not comply.
Detailed Explanation:
ANSI/TIA-942 evaluates data centers across several areas, including mechanical, electrical, architectural, and telecommunications. The overall rating reflects the lowest rated category, ensuring that no aspect of the data center's design or operation falls below the specified level. Thus, in this case, the architectural rating of 2 dictates the final rating, ensuring a comprehensive and balanced assessment of reliability and resilience across all aspects.
EPI Data Center Specialist References:
EPI Data Center Specialist training aligns with ANSI/TIA-942, stating that the final rating must reflect the lowest score to ensure comprehensive reliability across all critical infrastructure categories. This avoids overstating the data center's resilience and ensures uniform standards across areas.
質問 # 27
Management has requested a 15-minute battery bank assuming full load on the UPS. The UPS vendor has provided the following specifications of the UPS:
* Rated power: 30 kVA
* Rectifier input voltage: 400 V/3 phase
* Rectifier input power factor: 0.8
* Battery rated voltage: 384 V
* Number of cells: 192
* End of discharge voltage: 308 V
* Inverter output voltage: 400 V/3 phase
* Inverter output power factor: 0.8
What information is missing to perform the battery calculation?
- A. Inverter efficiency
- B. UPS efficiency
- C. Load imbalance on the phases
- D. Available battery charging current
正解：B
解説：
To determine the required capacity of the battery bank for the 15-minute runtime at full load, one must know the total power requirement that the battery bank must supply. The specifications provided include most of the necessary details, such as rated power, input voltage, battery voltage, and discharge voltage. However, one critical piece of information is missing: the UPS efficiency.
Detailed Explanation:
In a data center UPS system, the battery bank is designed to supply power for a set duration when there is an input power failure. The UPS efficiency affects the actual power the UPS can deliver to the load compared to the power it draws from the batteries. The efficiency factor is necessary to accurately calculate the required capacity of the battery bank since it determines how much input power is needed from the batteries to supply the load at full capacity. The formula typically used to determine battery capacity involves factoring in UPS efficiency, as it allows you to understand the losses within the UPS system.
If UPS efficiency is not considered, there would be an inaccurate estimation of the actual power needed from the batteries. For instance, if a UPS has 90% efficiency, only 90% of the power drawn from the batteries reaches the load. Without knowing this efficiency, it is not possible to calculate the battery bank size accurately, as you cannot accurately estimate the losses within the UPS itself.
EPI Data Center Specialist References:
According to EPI Data Center Specialist training, understanding the UPS efficiency is essential for battery sizing. Without it, the calculations could lead to either undersizing or oversizing the battery bank, which affects both reliability and cost-effectiveness of the UPS system. The EPI Data Center Specialist course emphasizes that battery sizing must account for all losses within the UPS system, with efficiency being a primary factor in these calculations.
質問 # 28
You are allowed to use a calculator for this question. A battery bank is rated at a total capacity of 600 Ah. Calculate how much charging current the rectifier should be able to supply as charging current.
- A. 80 Amperes
- B. 12 Amperes
- C. 60 Amperes
- D. 30 Amperes
正解：D
解説：
To determine the charging current for a battery bank, a general rule of thumb is that the charging current should be 5% of the total battery capacity. For a battery rated at 600 Ah, this calculation would be:
600 Ah×0.05=30 Amperes600 \, \text{Ah} \times 0.05 = 30 \, \text{Amperes}600Ah×0.05=30Amperes This ensures the battery is charged efficiently without overloading the rectifier or risking battery damage.
Detailed Explanation:
Battery charging current is typically set as a percentage of the battery's capacity to balance effective charging with longevity and safety. A 5% charging rate is standard for lead-acid batteries, which would be 30 Amperes for a 600 Ah battery bank.
EPI Data Center Specialist References:
EPI standards recommend calculating charging currents based on a percentage of the battery capacity to ensure safety and efficiency, aligning with best practices for battery management in data centers.
質問 # 29
The building in which the computer room is housed is required to have a sprinkler system. The building is therefore equipped with a wet pipe system.
What action, if any, should you recommend for the computer room?
- A. Replace the wet pipe system with a pre-action system.
- B. Replace the wet pipe system with a dry pipe system.
- C. Replace the wet pipe system with a deluge system.
- D. Maintain the current wet pipe system.
正解：A
解説：
In computer rooms, replacing a wet pipe system with a pre-action system is advisable. Pre-action systems provide additional protection by requiring two triggers (e.g., heat and smoke) before water is released, minimizing the risk of accidental discharge and water damage, which is crucial for safeguarding sensitive IT equipment.
Detailed Explanation:
Wet pipe systems contain water in the pipes at all times, which poses a higher risk of accidental discharge. Pre-action systems, however, only fill the pipes with water upon detection of a fire, reducing the risk of water-related damage due to leaks or malfunctions. This approach is considered best practice for environments housing sensitive electronic equipment.
EPI Data Center Specialist References:
EPI advises using pre-action fire suppression in data centers to reduce risks associated with accidental water release, providing a safer and more controlled fire response that better protects critical infrastructure.
質問 # 30
The UPS of a data center, with an ANSI/TIA-942 Rating-4, is installed with the rectifier connected to power feed A and the bypass/reserve line input connected to power feed B.
To which feed will the output of the UPS be synchronized?
- A. Feed A
- B. The UPS will not synchronize to any of the feeds but use an internal clock to set the output voltage and frequency
- C. Depends on the setting of the UPS, as the UPS can normally be set to either feed
- D. Feed B
正解：C
解説：
For a UPS system in a Rating-4 data center, the synchronization of output can indeed depend on the specific settings of the UPS. Generally, such systems allow for flexible configuration where the output can be synchronized to either power feed A or B, depending on which feed is preferred for stability or redundancy purposes.
Detailed Explanation:
In dual-feed setups, such as those in high-redundancy data centers, the UPS can be set to synchronize with either feed. This ensures that the UPS maintains continuity in case one feed becomes unstable or fails. The flexibility to choose synchronization to either feed enhances the resiliency and reliability of power supply, which is critical in Tier IV (Rating-4) facilities where uptime is paramount.
EPI Data Center Specialist References:
The EPI Data Center Specialist course underscores the importance of configurable UPS systems in Rating-4 data centers, where redundancy and continuous power are critical. By allowing synchronization to either feed, the UPS can maintain the highest level of reliability, which aligns with the rigorous standards expected in such environments.
質問 # 31
A new network storage device in a non-standard size rack of approximately 600 kg/1,300 lbs is going to be installed in the data center.
Are new floor loading calculations required?
- A. No, specifications of equipment brought into the data center will already be known during the design of the data center, and therefore the floor will be able to handle it.
- B. Yes, additional floor loading calculations need to be done by the floor manager, which should be verified by the safety engineer.
- C. No, as long as the equipment is less than 700 kg/1,500 lbs it will be within the limits.
- D. Yes, a structural engineer, approved/endorsed by the building owner, should carry out new floor loading calculations.
正解：D
解説：
For heavy equipment, such as a network storage device weighing approximately 600 kg/1,300 lbs, new floor loading calculations are indeed required, particularly since the rack is non-standard. A structural engineer, approved by the building owner, should conduct these calculations to ensure the floor can safely support the new load without risking structural integrity.
Detailed Explanation:
Data centers are designed with specific floor load ratings, which are determined during the design phase based on anticipated equipment. When adding or replacing equipment that is significantly heavy or non-standard, reassessing the floor's capacity is essential to avoid overloading. A structural engineer has the expertise to verify if the existing floor can accommodate the weight and, if not, can recommend reinforcement measures.
This step ensures compliance with safety standards and helps prevent damage to the infrastructure, which could lead to costly repairs or even catastrophic failure in extreme cases.
EPI Data Center Specialist References:
EPI Data Center Specialist training advises that any changes in the data center load, particularly involving non-standard and heavy equipment, warrant a structural assessment. Ensuring compliance with floor load capacity is a critical safety and operational concern, as underscoring data center infrastructure reliability and safety is a priority in EPI's best practices.
質問 # 32
A data center requires an audit to find out whether it conforms with ANSI/TIA-942 Rated-3 (concurrently maintainable).
Will the network architecture be part of this audit?
- A. Yes, amongst other aspects, the network architecture should be Rated-3 compliant with the requirements of ANSI/TIA-942.
- B. Yes, but only if the network administration does not comply with ANSI/TIA-606.
- C. No, as concurrently maintainable only applies to electrical and mechanical (power and cooling).
- D. No, only the type of cabling used will be audited.
正解：A
解説：
For a Rated-3 data center, network architecture is indeed a key component of the audit under ANSI/TIA-942. This rating requires concurrent maintainability across all systems, including telecommunications infrastructure. The network architecture must therefore meet specific redundancy and reliability standards to ensure uninterrupted operations during maintenance or failure of any single component.
Detailed Explanation:
Rated-3 requirements extend beyond electrical and mechanical systems to include network architecture. This ensures that telecommunications systems are also designed for concurrent maintainability, thus contributing to overall uptime and resilience.
EPI Data Center Specialist References:
EPI endorses comprehensive assessments for Rated-3 facilities, emphasizing that network systems must meet standards for redundancy and concurrent maintainability, which align with ANSI/TIA-942's holistic approach to data center reliability.
質問 # 33
What is a potential disadvantage of using a hypoxic-based fire suppression system as a fire extinguishing system?
- A. It can only be used in computer rooms where you have sufficient positive pressure.
- B. It can only be used in computer rooms which have sufficient air changes per hour.
- C. It can only be used in non-continuous occupied areas.
- D. The gas containers need to be close to the hazard area.
正解：C
解説：
A hypoxic-based fire suppression system works by reducing the oxygen level in a room to below what is necessary to sustain combustion. This makes it effective in fire prevention, but it is not suitable for continuous occupancy by personnel. Low oxygen levels can cause discomfort or even health risks for people spending extended periods in the space. Therefore, these systems are typically deployed in areas where continuous human occupancy is not required, such as storage rooms or data halls with limited personnel access.
Detailed Explanation:
Hypoxic fire suppression systems lower oxygen levels to around 15-16%, which is safe for short periods but not sustainable for continuous occupancy without risk to health. Data center environments where staff need to spend long periods monitoring and maintaining equipment would need alternative systems, like gas-based suppression that allows for safe evacuation rather than oxygen reduction.
EPI Data Center Specialist References:
The EPI Data Center Specialist curriculum emphasizes that fire suppression systems must be chosen based on occupancy requirements. Hypoxic systems are specifically noted as unsuitable for spaces requiring continuous human presence due to the low oxygen environment they create.
質問 # 34
What should you consider when using raised floor tiles with air deflectors or louvers?
- A. Tiles with air deflectors or louvers can only be used to cool storage equipment.
- B. Tiles with air deflectors or louvers do not allow for a flexible cooling solution.
- C. Tiles with air deflectors or louvers will reduce the cooling capacity of the tile.
- D. Tiles with air deflectors or louvers can be very heavy.
正解：D
解説：
Raised floor tiles with air deflectors or louvers are typically heavier than standard tiles due to the additional materials and mechanisms used to direct airflow. The added weight can pose challenges for installation and adjustment, and consideration must be given to the floor's load capacity and ease of maintenance.
Detailed Explanation:
Tiles with deflectors or louvers help direct airflow, enhancing cooling efficiency by focusing cool air where needed. However, these tiles are often heavier, which can affect handling and require reinforced raised floor systems. It's essential to factor in the weight for any floor tile replacements or installations to ensure they are compatible with the raised floor's structural capacity.
EPI Data Center Specialist References:
EPI data center design training mentions the potential impact of heavy tiles on floor handling and load capacity. Data center operators need to plan for safe handling and load-bearing capacity when using such specialized tiles.
質問 # 35
Do you need to consider bullet (ballistics) protection when designing a data center?
- A. Bullet (ballistics) protection is only required if the facility is a potential target or the building is in the vicinity of a potential target.
- B. Bullet (ballistics) protection is required by ANSI/TIA-942 for data centers Rated 3/4.
- C. Bullet (ballistics) protection is required by ANSI/TIA-942 for all data centers.
- D. Bullet (ballistics) protection is only required when the data center is located in an area with a high crime rate.
正解：A
解説：
Bullet (ballistics) protection is typically considered only for data centers that are potential targets or located near such targets. While ANSI/TIA-942 does not specifically require bulletproofing for all data centers, it is prudent to consider it based on location risk assessments, especially if the facility is in a high-risk area or near critical infrastructure that could attract threats.
Detailed Explanation:
Protective measures like bulletproofing depend on the threat landscape and the data center's exposure to risks such as crime or terrorism. Assessments for physical security are typically customized based on location-specific risks rather than being universally required by data center standards.
EPI Data Center Specialist References:
EPI guidelines emphasize customizing physical security measures based on threat assessments, suggesting that bulletproofing is appropriate in specific circumstances where the facility's risk profile justifies additional security measures.
質問 # 36
A data center is located in an area where the demand for power is higher than the utility power company is able to deliver. This results in frequent power outages and, therefore, power shedding (scheduled/controlled power shutdown for areas) is frequently applied. The mains power is more than 650 hours/year not available.
What type of generators should be installed?
- A. Standby generators should be installed in at least an N+1 configuration
- B. Continuous generators should be installed, at least in an N+1 configuration
- C. Continuous generators should be installed; no N+1 configuration is needed as the generators will run all the time
- D. A combination of standby-, prime-, and continuous-generators, as the duration of the power outage is unpredictable. The total available capacity of the generators should be at least 500% of the data center load
正解：B
解説：
In areas with frequent and extended power outages, continuous generators with at least an N+1 configuration are necessary to ensure consistent power availability. Continuous generators are designed for prolonged operation, making them suitable for scenarios where utility power is frequently unavailable, as in this case with outages exceeding 650 hours per year. An N+1 configuration ensures redundancy, which is critical for maintaining uptime in a high-availability data center.
Detailed Explanation:
Continuous generators provide reliable power over long durations, unlike standby generators, which are intended only for short-term use. The N+1 configuration ensures that there is always an additional generator available in case of failure, thus maintaining power supply even if one generator goes offline.
EPI Data Center Specialist References:
EPI best practices recommend continuous generators with redundancy for data centers located in areas with high power instability to maintain reliability and continuous operation.
質問 # 37
An air-conditioner unit needs to be selected. Two types are available:
Unit-A has a Sensible Heat Ratio (SHR) of 0.7.
Unit-B has a Sensible Heat Ratio (SHR) of 0.9.
From an efficiency point of view, which one should be selected?
- A. Unit A
- B. Unit B
- C. Not relevant, as Sensible Heat Ratio is only specified for air-conditioner equipment to indicate the ratio between intake temperature and exhaust temperature.
- D. It does not matter, as the Sensible Heat Ratio has nothing to do with efficiency.
正解：B
解説：
From an efficiency standpoint, Unit B with a Sensible Heat Ratio (SHR) of 0.9 is preferable. A higher SHR indicates that a greater proportion of the air conditioner's capacity is dedicated to sensible cooling (temperature reduction) rather than latent cooling (moisture removal). In data centers, sensible cooling is more critical since IT equipment primarily generates heat without adding significant moisture.
Detailed Explanation:
An SHR of 0.9 means that 90% of the cooling capacity is used for sensible cooling, which is more efficient for environments like data centers where humidity control is typically less of a concern. Opting for an air conditioner with a higher SHR ensures that most of the cooling energy is focused on temperature reduction, making Unit B more efficient in this scenario.
EPI Data Center Specialist References:
EPI data center best practices recommend choosing cooling units with higher SHR values in data centers, as they better match the cooling needs of IT equipment. High SHR units improve cooling efficiency by concentrating on sensible heat removal, which is vital for maintaining the optimal thermal environment.
質問 # 38
When shielding material reaches its saturation point, what will be the impact?
- A. The shielding material will no longer be able to attenuate (reduce) additional EMF.
- B. The shielding material will reach its optimal shielding performance state.
- C. The shielding material will increase its permeability factor.
- D. The shielding material will reach its maximum electrically charged state.
正解：A
解説：
When shielding material reaches its saturation point, it can no longer effectively attenuate additional EMF. At saturation, the material's ability to absorb or redirect magnetic fields is exhausted, meaning it cannot provide further shielding beyond this point. Additional EMF exposure would pass through the material without significant reduction.
Detailed Explanation:
Saturation occurs when the material's magnetic domains are fully aligned with the magnetic field, leaving no capacity to absorb or deflect further EMF. This can happen with high EMF levels, beyond the material's design limits, resulting in a breakdown of shielding effectiveness.
EPI Data Center Specialist References:
EPI guidelines on EMF management indicate that selecting appropriate shielding materials with sufficient capacity is essential to prevent saturation and ensure continuous protection. Saturation limits should be considered during design to avoid compromised shielding performance.
質問 # 39
You are changing the design of the fire suppression system for your computer room from a halocarbon fire suppression system into an inert-based fire suppression system. Could you use the same formula to calculate the gas content for the gas?
- A. No, there is a significant difference in the formula for the different types of fire suppression gases.
- B. Yes, as long as you change the 'S' factor of the formula to reflect the gas type used.
- C. Yes, as long as you take the difference between the net and gross volume into account.
- D. Yes, as long as you use the same units of measure, i.e., kg/m³ or lbs/ft³.
正解：A
解説：
The formula used to calculate the gas content differs significantly between halocarbon and inert-based fire suppression systems. Halocarbon systems function by absorbing heat, while inert systems work by reducing oxygen levels. Due to these differences in fire suppression mechanisms, distinct formulas are applied, factoring in the specific properties of each gas type and the required concentration levels.
Detailed Explanation:
Halocarbon systems like FM200 require a formula that accounts for the concentration needed for cooling, while inert gases like nitrogen or argon need a formula that calculates the volume based on oxygen displacement. As the design concentration and characteristics of these gases differ, it's essential to use the correct formula specific to the gas type.
EPI Data Center Specialist References:
EPI recommends consulting the specific design requirements and formulas provided by each gas manufacturer when switching fire suppression systems to ensure the correct amount of gas is deployed for effective fire suppression.
質問 # 40
What is the main disadvantage of using a ToR (Top of Rack) design?
- A. There will be more switches to manage.
- B. A single ToR (Top of Rack) switch is more expensive than an EoR (End of Row) switch.
- C. A ToR (Top of Rack) switch has only optical interfaces.
- D. You need a separate rack to install all your ToR (Top of Rack) switches.
正解：A
解説：
A Top of Rack (ToR) design typically requires more switches because each rack has its own switch to manage network connections, as opposed to End of Row (EoR) or centralized designs, which consolidate switches. While ToR designs improve cabling efficiency and reduce latency, they also increase the number of switches, thus raising management complexity and potentially increasing capital and operational costs.
Detailed Explanation:
In a ToR setup, each rack's individual switch allows for quick access and streamlined cabling within the rack. However, this setup means more devices to configure, monitor, and maintain, which can increase administrative overhead and network management complexity.
EPI Data Center Specialist References:
EPI documentation notes that ToR designs can improve performance but also lead to increased management needs due to the higher switch count, making them less ideal in environments where simplified network management is prioritized.
質問 # 41
When installing a raised floor, can we use a spirit level bar to level the floor?
- A. No, because using a spirit level bar, a measurement error will be transferred from pedestal to pedestal.
- B. Yes, spirit level bars can be used as long as their length is longer than 60 cm/2 ft (the size of a typical raised floor tile).
- C. Yes, but spirit level bars can only be used in the vertical plane.
- D. Yes, using a spirit level bar for raised floors higher than 40 cm is preferred.
正解：A
解説：
A spirit level bar should not be used for leveling a raised floor, as measurement errors are likely to propagate from one pedestal to the next. Spirit levels can introduce cumulative errors, leading to uneven floors, particularly in large installations where precise leveling is critical.
Detailed Explanation:
Using a laser level or a precision leveling device is recommended to ensure accuracy across all floor tiles. Spirit levels, while adequate for short spans, can transfer small inaccuracies from one pedestal to another, which can cause alignment issues and floor instability over time.
EPI Data Center Specialist References:
EPI data center guidelines discourage the use of spirit levels for raised floors. Instead, they advocate for precision tools like laser levels that ensure consistency and accuracy in large-scale installations, aligning with best practices for raised floor construction.
質問 # 42
A data center has its own power supply from the public utility and receives chilled water supply from the building owner.
What needs to be taken into consideration when calculating the PUE?
- A. PUE calculations are not possible in shared buildings
- B. Nothing, as the chiller plant in the building also uses electrical power
- C. You will need to take a weight factor of 0.4 for district chilled water into consideration
- D. You will need to take the value for COP of the chiller plant into consideration
正解：C
解説：
When calculating Power Usage Effectiveness (PUE) in a data center that uses chilled water from an external source, like from a building owner, a weight factor for district chilled water must be applied. This is because PUE calculations aim to measure the energy efficiency of the data center's own operations, and external utilities like district chilled water aren't directly powered by the data center. A weight factor of 0.4 is typically used to account for the energy consumed to produce and deliver the chilled water, reflecting the indirect impact on the data center's total energy consumption.
Detailed Explanation:
PUE is calculated as the ratio of the total facility energy to the IT equipment energy. If the cooling is provided by an external chilled water source, it's necessary to adjust the calculations to accurately reflect the energy impact. By incorporating the 0.4 weight factor, data centers can calculate a more accurate PUE, aligning with standard methods and industry best practices.
EPI Data Center Specialist References:
EPI training on PUE highlights the importance of adjusting for external energy sources, such as district cooling, in the calculations. This ensures that PUE values remain accurate and comparable across different data centers, even when external utilities are used.
質問 # 43
A computer room with a raised floor has been designed with racks in a hot/cold aisle setup.
What should you recommend for the placement of down-flow air conditioners?
- A. Air conditioners perpendicular to (at the end of the row of) the Cold-Aisle
- B. Air conditioners should always be placed at both sides of each row of racks
- C. Air conditioners perpendicular to (at the end of the row of) the Hot-Aisle
- D. Air conditioner placement has no influence on cooling effectiveness and efficiency. Hence, they can be placed at any convenient location.
正解：A
解説：
In a hot/cold aisle configuration, placing down-flow air conditioners perpendicular to the cold aisle ensures that cool air is directed efficiently into the cold aisles where server intakes are located. This layout allows for optimal cooling performance by aligning the airflow directly with the equipment intakes, minimizing hot spots and enhancing cooling efficiency.
Detailed Explanation:
With a raised floor design, cold air from the air conditioners is supplied into the cold aisle, where server intakes are located. Positioning the air conditioning units perpendicular to the cold aisles ensures that cool air is delivered directly into these aisles, preventing air mixing and optimizing cooling. This setup takes full advantage of the airflow management strategy inherent to the hot/cold aisle configuration.
EPI Data Center Specialist References:
EPI guidelines on cooling emphasize that down-flow air conditioners should be positioned to maximize the effectiveness of cold aisle delivery, which improves cooling efficiency and helps maintain consistent temperatures across server racks.
質問 # 44
Which formula is correct?
- A. Phase-to-Neutral Voltage = (Phase-to-Phase voltage * 1.732) / Phase-to-Neutral Voltage
- B. Phase-to-Neutral Voltage = Phase-to-Neutral voltage * 1.732
- C. Phase-to-Neutral Voltage = Phase-to-Phase voltage /1.732
- D. Phase-to-Neutral Voltage = Phase-to-Phase voltage * 1.732
正解：C
解説：
The correct formula for calculating Phase-to-Neutral Voltage in a three-phase power system is Phase-to-Neutral Voltage = Phase-to-Phase Voltage / 1.732. This formula applies to balanced three-phase systems, where 1.732 (or √3) represents the relationship between line-to-line and line-to-neutral voltages.
Detailed Explanation:
In three-phase systems, Phase-to-Phase Voltage is higher than Phase-to-Neutral Voltage by a factor of √3. Dividing the phase-to-phase voltage by 1.732 gives the phase-to-neutral voltage, which is critical for understanding power distribution in three-phase electrical systems commonly found in data centers.
EPI Data Center Specialist References:
EPI electrical training highlights the importance of knowing these calculations for designing and maintaining balanced power systems, which are essential for stable and efficient data center operations.
質問 # 45
What is the minimum requirement for the power feeds to the building for a Rated-3 data center based on the ANSI/TIA-942 standard?
- A. One feed from one substation split over two separated distribution boards in separate rooms
- B. Two feeds coming from two different substations, one power company is acceptable
- C. Two feeds entering the data center building from one substation
- D. Two feeds coming from two different substations, one power company is not acceptable
正解：B
解説：
The minimum requirement for power feeds to a Rated-3 data center according to ANSI/TIA-942 is to have two independent power feeds, which can come from two different substations provided by the same power company. This ensures redundancy and concurrent maintainability, as each feed can support the load independently during maintenance or failure of the other.
Detailed Explanation:
The separation by two substations ensures resilience in case of a localized outage or substation maintenance, aligning with Rated-3 requirements for uninterrupted operation. ANSI/TIA-942 permits these feeds from a single utility provider as long as they are supplied from distinct substations.
EPI Data Center Specialist References:
EPI underscores the importance of dual power feeds from separate substations for Rated-3 facilities, highlighting that the ability to draw from different substations aligns with redundancy requirements for high availability.
質問 # 46
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