問43
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無停電電源装置の利用方法に関する説明のうち, 適切なものはどれか。
平成23年度 秋期 ITパスポート試験 問43
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This question's explanation and your answers so far.
解説
問 43
Incorrectア
A UPS is a stationary device built into the power supply system of computers, servers, network equipment, and the like; it differs from a spare battery for a mobile phone (a power bank) in both purpose and form. In addition, the purpose of a UPS is not “to allow long-time use,” but to get through the short period right after a power outage begins, so this choice is wrong on that point as well.
Incorrectイ
With the battery capacity of a UPS, power can be supplied for only several minutes to a dozen or so minutes at most, so it cannot keep supplying power through a long power outage. Preparing for a long outage requires a private power generator (an emergency generator); the UPS is used together with it only as a bridge until that generator starts up.
- ウ
正解 An uninterruptible power supply (UPS) uses its built-in battery to “temporarily supply power during a power outage,” and it also serves to “prevent the effects of momentary voltage drops (voltage sags) and instantaneous interruptions.” Even when a power failure occurs, it keeps supplying power for about several minutes to a dozen or so minutes, so during that time you can save the data you are working on and shut the equipment down properly, or buy time until a private power generator starts up. This makes it possible to avoid data corruption and disk failures caused by a sudden loss of power. Choice ウ correctly states these two roles (temporarily supplying power during an outage, and preventing the effects of momentary voltage drops), so it is appropriate.
Incorrectエ
A UPS is a device designed on the assumption that it is charged from utility power while in use, so it cannot be used to run a computer for a long time outdoors where there is no power source. Such use calls for a generator or a large-capacity portable power station, which is different from the purpose of a UPS.
ここがポイント
- The role of a UPS is to supply power for “only a short time” during an outage — enough to shut down safely or switch over to a private generator — and to protect computers from power disturbances such as momentary voltage sags and brief interruptions.
- Remember this division of roles: measures against a long power outage are handled by a private power generator (an emergency generator), not by a UPS; the UPS is combined with it as a bridge until the generator starts up.
用語