HP Integrity rx6600 Site Preparation Guide, Third Edition - HP Integrity rx660 - Page 13

Glossary A-B Apparent power ASHRAE Standard 52-76 ASL board Btu/h A value of power for ac circuits that is calculated as the product of RMS current times RMS voltage, without taking the power factor into account. Industry standard for air filtration efficiency set forth by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc. Above sea level. A printed circuit assembly (PCA). Also called a card or adapter. The abbreviation for British thermal units. The amount of heat required to raise one pound of water one degree fahrenheit per hour, a common measure of heat transfer rate. C CFM Chilled water system CompactPCI The abbreviation for cubic feet per minute, commonly used to measure the rate of air flow in an air conditioning system. A type of air conditioning system that has no refrigerant in the unit itself. The refrigerant is contained in a chiller, which is located remotely. The chiller cools water, which is piped to the air conditioner to cool the space. The newest specification for PCI-based industrial computers is called CompactPCI. It is electrically a superset of desktop PCI with a different physical form factor. See http://www.picmg.org for details. D-K Dehumidification Derate Downflow EIA unit Humidification Inrush current KVA The process of removing moisture from the air within a critical space. To lower the rated capability of an electrical or mechanical apparatus. Refers to a type of air conditioning system that discharges air downward, directly beneath a raised floor, commonly found in computer rooms and modern office spaces. The Electronic Industries Association (EIA) defines this unit of measurement to be 1.75 inches in height. So then, 1U equals 1.75 inches (1U equals 44.45 mm). The process of adding moisture to the air within a critical space. The peak current flowing into a power supply the instant ac power is applied. This peak is usually much higher than the typical input current due to the charging of the input filter capacitors. When switching power supplies are first turned on, they present high initial currents as a result of filter capacitor impedance. These large filter capacitors act like a short circuit, producing an immediate inrush surge current with a fast rise time. The peak inrush current can be several orders of magnitude greater than the supply's typical current. Abbreviation for kilovolt-amperes. (1,000 x volt-amperes). L-N Latent cooling capacity Leakage current Maximum input current NEBS An air conditioning system's capability to remove heat from the air. A term relating to current flowing between the ac supply wires and earth ground. The term does not necessarily denote a fault condition. In power supplies, leakage current usually refers to the 60 Hertz current, which flows through the EMI filter capacitors that are connected between the ac lines and ground. The operating current of the product equal to the maximum load divided by the minimum input voltage. All electronic equipment has the potential to interfere with other electronic equipment. Interference can be caused by electromagnetic radiation, the grounding system, the electrical power connection, excessive heat, or blocking the natural airflow, and connecting wires or 13