Uninterruptible Power Supply (UPS)
A power supply that continuously provides output power to the load without interruption.

VA (volt-amperes)
Measurement of the electrical potential (volts) multiplied by the electrical current (amperes);
also known as apparent power.

Watt
The unit of measurement that expresses actual electrical consumption; also known as real power.

KVA
Apparent power (volts multiplied by amperes) measured in units of 1,000, e.g. 18,000VA is 18KVA.

Power Factor
True power (watts) divided by apparent power (VA).

AMP
The quantitative unit measurement of electrical current.

Sine Wave
A wavefrom of a single frequency alternating current whose displacement is the sine of an angle proportional to time or distance.

Single-Phase
Energized by a single alternating voltage.

Blackout
Total loss of utility power for more than 8.35ms. Can cause hard drive crashes, data loss and prolonged downtime.

Sag
A short-term decrease in voltage. Generally caused by large loads starting up, utility power line faults or rolling brownouts created by utility companies on peak-use days. Can cause workstations and servers to freeze, hard drives to garble or misplace dara, and motor parts to wear faster.

Surge
A short-term increase in voltage, typically lasting at least 1/120 of a second.
Usually caused by drops in electrical demand and widespread equipment shutdown.
Can cause electronic wear and premature equipment failure.

Spike
An instantaneous, dramatic increase in voltage.
Most often caused by lightning; sometimes by power coming back on after a blackout.
Can cause aborted modem transfer, microchip failures and "fries" hardware.

Noise
Also known as harmonics, electro-magnetic interference (EMI), and radio frequency interference (RFI). Created by neighboring office equipment or machinery on the same power line. Can corrupt data and cause glitches.

Full-Load
Load that equals the UPS capacity.

Runtime
The length of time that a UPS will support a given load while running on battery during a power outage.

Harmonics
Multiples of a fundamental frequency, e.g., 120Hz is the second harmonic of 60Hz, etc.; such excessive content distorts the normal Sine Wave form.

Hot-Swappable
Batteries can be replaced without powering down connected equipment and /or the system.

SNMP Adapter (Simple Network Management Protocol)
Hardware that allows monitoring and management of remote UPSs that protect key network devices such as servers, routers and hubs.