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J - M

J      [A B C D E F G H I J K L M N O P Q R S T U V W X Y Z]

Joule - The mks unit of work or energy equivalent to heat generated in 1 second by 1 ampere flowing through 1 ohm. A watt/second. A measurement of work in time. 1 joule equals 0.0002778 watt/hours. 1 kilowatt hour is equivalent to 3,600,000 joules.

K      [A B C D E F G H I J K L M N O P Q R S T U V W X Y Z]

kcmil - Thousand Circular Mil; wire size for multiple stranded conductors over 4/0 AWG in diameter. Formerly MCM.

k - kilo, used to express 1000 (10 to the +3rd power) times the standard unit.

kV - kilo-Volts; 1000 Volts potential.

kVA - kilo-Volt-Ampere; 1000 Volt Amperes; a measure of apparent power.

kW - kilo-Watt; 1000 Watts; a measure of real power.

L      [A B C D E F G H I J K L M N O P Q R S T U V W X Y Z]

Lagging Load - An inductive load with current lagging voltage. Since inductors tend to resist changes in current, the current flow through an inductive circuit will lag behind the voltage. The number of electrical degrees between voltage and current is known as the phase angle. The cosine of this angle is equal to the power factor (linear loads only).

LAN - Local Area Network. See Ethernet. The means by which a local community of users and workgroups can share information and resources electronically.

LED - Light Emitting Diode, a high reliability, illuminating device used as an indicator of state or status. Available in red, green, amber and blue.

Leading Load - A capacitive load with current leading voltage. Since capacitors resist changes in voltage, the current flow in a capacitive circuit will lead the voltage.

Leakage Current - The current flowing from the input terminals of the electrical equipment and the chassis at a specified voltage. This is a safety consideration so designs minimize this current to typically less than 5 mA for commercial systems and less for military and medical systems.

Line Conditioner (Power Conditioner) - A device that optimizes the quality of commercial power.  By definition, an uninterruptible power supply (UPS) system is a line conditioner, but a line conditioner is not always a UPS.

Line Interactive - A UPS containing an off-line inverter that must transfer on during a blackout, but provides faster transfer times than an offline UPS. Power conditioning and surge suppression are provided to protect the connected load.

Linear Load - A load in which the current relationship to voltage is constant based on a relatively constant load impedance.

Load -Equipment that receives power from a power supply, UPS or PDU.

Load Segments - Groups of receptacles on the rear panel of a power supply or UPS that can be independently controlled.

Load Sequencing - The ability to selectively turn on or off specific loads in a preset pattern. Some UPS and PDU models are able to perform load sequencing on startup and/or shutdown. Benefits include reduced inrush and ability to start a specific load before another is started.

Load Shedding - The ability to selectively shut off a set of output receptacles, extending the capacity of the UPS battery. Some PowerStation UPS models are able to shed less critical loads by turning off selected output receptacles during an extended power failure while maintaining power to the more critical load(s) on the remaining output receptacles.

M      [A B C D E F G H I J K L M N O P Q R S T U V W X Y Z]

M - Mega, used to express 1,000,000 (10 to the +6th power) times the standard unit, i.e. MVA.

µ - micro, used to express 0.000001 (10 to the -6th power) times the standard unit, i.e. µF

m - milli, used to express 0.001 (10 to the -3rd power) times the standard unit, i.e. mA

Magnetic Synthesizer - A three-phase ferroresonant based system with zigzag output windings to allow the Ferro to handle unbalanced loads.

Maintenance free battery - This means that during the normal operation of the battery, there will not be a need to add water or electrolyte.

Make-Before-Break - Operational sequence of a switch or relay where the new connection is made prior to disconnecting the existing connection.

Manual Bypass Switch - (MBS) A manually operated transfer switch used to bypass the major electronics in the UPS, so the UPS can be serviced without power interruption.

MIB - Management Information Base. The database of information (or variables) related to a particular network device or collection of network devices. The MIB is a collection of stored guidelines that allow a NMS to know what information can be provided by the various devices on the network which might be polled for status information. The popularity of SNMP has resulted in the development of standards for storing data critical to network operation, the Management Information Base (MIB). MIB-II, the latest generation of network management MIBs, stores data on TCP/IP traffic, routing, configuration and errors. MIB-II has improved support for multi-protocol devices and allows the NMS to control SNMP operation

MOV - A Metal Oxide Varistor. A MOV is a voltage sensitive breakdown device which is commonly used to limit overvoltage conditions (electrical surges) on power and data lines. When the applied voltage exceeds the breakdown point, the resistance of the MOV decreases from a very high level (thousands of ohms) to a very low level (a few ohms). The actual resistance of the device is a function of the rate of applied voltage and current. A varistor is a very rugged voltage clamping device capable of absorbing very large currents without damage.

MTBF - Mean Time Between Failure. The measurement of the reliability of equipment expressed in the average operational hours before a service interrupting failure. Based upon either actual operating data or calculated data per MIL-HDBK 217.

MTTR - Mean Time To Repair. The time to repair a piece of equipment on the average.

Multinational Input - Refers to ETI products being able to operate from standard voltages of 100 vac, 120 vac, 200 vac, 220 vac or 240 vac having either a 50 or 60 Hz frequency. This covers 99+% of the world.