There’s a lot of industry terms to sort through in manufacturing. Explore our glossary for quick definitions of frequently used manufacturing terms and acronyms.


Advanced Battery Management
Advanced Battery Management- Firmware management available on some UPS systems to charge, rest and refresh batteries designed to increase battery life.
A device that converts mechanical energy into electrical energy. The alternator is also referred to as the gen end. Brushless alternators are often used in large generators, while permanent magnets are commonly used in smaller generators.
Alternating Current (AC)
Current flow of electric charge that periodically reverses direction, typically 50 or 60 Hz.
American Rental Association (ARA)
The American Rental Association is an international trade association for the equipment rental industry.
American Public Power Association (APPA)
A national service organization that represents 2000 municipal and other state or local publicly owned electric utilities spread across the United States.
Measurement of the strength or intensity of an electric current in ampere.
Automatic Transfer Switch
A mechanical device that switches an electrical load from a preferred source, usually a utility service, to an alternate source, usually an emergency generator. It also incorporates controls to start and stop the generator and timer functions to coordinate the transfer.
Battery Charge Rectifier
This component changes AC voltage from the battery charge windings to DC voltage for charging a battery. This is found only on very small generators.
Battery Current Limit
Process of electronically limiting the amount of current at which batteries can be charged so that the load on the UPS can run simultaneous to battery charging without exceeding the maximum input feeder amperage available to the UPS.
Battery String
The minimum amount of batteries or battery cells wired in series necessary to power the UPS with an absolute minimum runtime makes up one string. Additional battery runtime is attained by adding additional strings in parallel up to a maximum amount determined by the capability (size) of the UPS’ battery charger.
Sudden or unexpected disruption of electrical power.
Brushes are typically made of graphite or copper, they are conducting elements that maintain sliding electrical contact between static and moving elements. In order for a generator to function, brushes are typically used to help create a complete electrical circuit. Brushes are only used on extremely small and extremely large generators.
Backup Generators
A stand-by source of energy used to fill emergency load requirements during a sudden shortage or loss of power. Backup generators are usually diesel engine driven and can turn on automatically during a power outage, restoring power in under 10 seconds.
Battery Capacity
When speaking of battery systems, Battery Capacity is the amount of battery runtime available at a given load determined by a Battery Capacity Test. When speaking of individual batteries, Battery Capacity is the rating of the batteries in terms of its Amp Hour rating.
The core, also known as the stator core, is a stacked laminated cylindrical structure in a generator.
Critical Infrastructure Module
A portable modular data center, designed to reduce capital cost and quicker time to market.
Also know as electric current, this is the flow of particles charged by electricity. One of the effects that electric currents have is to induce magnetic fields, which are used for generator
Diesel Engine
An internal combustion engine in which fuel oil is ignited by heat produced from air compression. The most commonly bought industrial diesel engines are either rebuilt diesel engines or used diesel engines.
Diesel Generator
Diesel generators use a diesel engine and an alternator to generate electrical energy. They are commonly used for back-up or stand-by power. Benefits of a diesel generator include quick and automatic start up during power outages.
Direct Current (DC)
Current produced by storage battery with a unidirectional flow.
Supply of lower voltage electric power from a centralized substation to the point of end use.
Dual Fuel Generator
Also know as a bi-fuel generator. This refers to a generator engine that can run on diesel and gas simultaneously.
Double Conversion
Refers to the “double” conversion in a UPS of AC input power being converted to DC and then converted back into AC at the output of a UPS. Double conversion allows for transient protection due to the conversion process, as well as, is typically the method by which most online type UPS’ work.
Electrical Generating Systems Association (EGSA)
The Electrical Generating Systems Association (EGSA) is the world’s largest trade association dedicated to on-site electric power generation.
Electrical Line Noise
Deviations from a pure sine wave waveshape potentially due to harmonics, load types, etc. Noise can be minor and would show as small ripples on a sine wave or significant with large dips appearing the sine wave waveform.
Electric Generator
A machine that generates electricity from a source of mechanical energy. The electricity created serves as a power source for other machines.
Electromagnetic Interference (EMI)
Potential electrical interference of one piece of electronic equipment into a surrounding piece of electrical equipment and/or the environment. For example, keying a walkie talkie next to other electrical equipment may cause audible noise in an audio system or other noise on circuits of other electronic devices that may cause malfunctions or total failure, in some cases.
Engine Generator
Also known as a generator set, gen-set, or sometimes just a generator. An engine generator is the combination of an engine and an alternator working together to generate electric power.
Storing energy in a rotating mass form, Flywheel is a very active substitution of chemical batteries.
Flooded Batteries
Typically referred to as “wet cells,” flooded batteries contain actual liquid form electrolyte and are more maintenance intensive than sealed batteries.
A device that converts a source of mechanical energy (for example, a diesel or natural gas engine) into electrical energy.
Generator End
Also called an alternator.
A power generator that converts fuel into electrical power through the use of an engine and an alternator.
In order to meet the power needs at different points, a system of power lines, substations and generators, interconnected is used. This is a grid.
Hertz (Hz)
Unit of frequency that is equal to one cycle per second.
HVAC (Heating, Ventilation, and Air Conditioning) refers to the systems involved in maintaining an indoor environment.
Ignition Coil
Ignition coil supplies DC voltage to the spark plugs of generators running natural gas engines.
Input Voltage Range
Voltage range that is acceptable to the UPS for proper operation. The main input voltage range may differ from the bypass input voltage range in dual fed UPS.
Insulated Gate Bipolar Transistor (IGBT)
Current transistor technology type most commonly used in newer UPS systems.
Internal Bypass
When a UPS is in internal bypass, its static switch is active and the load is being fed by unprotected, non-battery backed up power (“street power”””).
Isolation Transformer
Transformer designed to isolate what it is feeding from upstream power source issues or configuration differences.
Measurement of electrical energy equivalent to the work done when a current of one ampere passes through a resistance of one ohm for one second.
Kilowatt (kW)
A unit of electric power, typically used to rate the power of commercial and industrial generators in the U.S.
Kilowatt-hour (kWhr)
Total number of kilowatts used per hour, when energy is being transmitted or used at a constant rate over a period of time.
kVA is kilovolt-ampere and is a unit of apparent power.
Line Conditioner
Smoothes the incoming power source to as close to a pure sine wave waveform as possible. Does not provide battery backup protection.
Load Bank
A machine that is used to test a generator’s ability to handle an electrical load.
Load Segment
A segment is a group of load. For example, one load segment might be Server Rack A while another segment might be everything powered by Server Rack B.
Built with permanent magnets, a magneto is a special kind of electrical generator that provides ignition to spark ignited engines.
Maintenance Bypass
Method of bypassing the UPS in a complete “wrap around” way so that the load can continue to be powered up while the UPS can be completely powered down for maintenance or even total replacement or upgrade.
Manual Bypass Switch (MBS)
Rotary switch or panel board of breakers designed to allow a UPS to be transferred to/from maintenance bypass and normal operation without interrupting the load at all barring mis-operation or a power failure while in maintenance bypass mode.
Motor Generator
A machine that is used to convert industrial amounts of electrical power to another form. Typically for frequency conversion.
N+X UPS Redundancy
Redundancy in a single UPS with multiple power modules or a UPS system with redundant UPS’ that can operate up to a rated KVA (N) with redundancy of (X). For example if a 500 KVA UPS system is N+2, there would be one or one set of primarily UPS’s that would carry the 500 KVA of load with 2 additional UPS or UPS sets that could carry the load if the primarily UPS failed or was taken offline for maintenance.
Non-Utility Generator
Connected to an electric utility system, a non-utility generator generates electricity and is capable of feeding excess energy into the utility system.
A specific period when power demand of a system is comparatively low. Counted from 10 p.m. until 6 a.m., from Monday through Saturday and during the whole day on Sunday by NERC.
Off-Peak Rate
This is the rate of cost for power used during Off-Peak periods.
Orderly Shutdown
Proper procedure of shutting down a UPS system with the least amount of impact to the load and minimizing damage potential to the UPS or other equipment.
Output Waveform (UPS)
Refers to the sine wave waveform leaving the UPS heading to the load.
Parallel Online UPS
Configuration where 2 or more UPS operate in parallel either to increase capacity (Two 500 KVAs to power 1000 KVA of load) or in parallel for redundancy in an N+X configuration.
Measurement of the maximum load that is consumed within a specified time period.
measures the uniform periodic change in amplitude or magnitude of an alternating current. Most industrial and commercial generators operate in a three-phase power system. In a three-phase power supply system, three conductors each carry an alternating current (of the same frequency) but the phase of the voltage on each conductor is displaced from each of the other conductors by 120 degrees.
Power Sag
A dip voltage typically temporarily on an AC power line.
is used for converting alternating current (AC) to direct current (DC), this process is called rectification.
Rated Voltage
The specific voltage measurement at which an engine generator is set to operate.
Normally used in control circuits, relay is a switch driven by a low current control circuit.
The moving part of an alternator (or electric generator).
Single Point of Failure
Single point of failure is a location in a redundant system where a single power’s failure results in loss of electrical power to the critical load. In any critical facility it is especially important to eliminate any singe points of failure.
Split-Phase UPS
Use of 2 or 3 power phases to create a useable voltage across the phases.
Standby Industrial Generator
A back-up source of electricity that operates automatically in the case of a loss of power. Standby generators are commonly used in Datacenters, Computer Rooms, Switching Offices, Process Centers, Laboratories, and Medical Facilities.
Standby (Backup) Service
Electrical service through a permanent connection not normally used, but available in lieu of, or as a supplement to, the usual source of supply.
Standby Emergency Power
The backup source of electrical energy that remains dormant and only starts functioning when a control device (or Automatic Transfer Switch) instructs it to.
Starting a UPS without input AC power and making AC in the inverter section from the battery alone.
The static or unmovable element of a generator.
Step Load
Increasing the load in steps by turning on sequential load segments or for testing purposes with a load bank, stepping from zero load to 25% to 50% to 75% to 100% and stepping back down again.
Turbine Generator
A generator set that utilizes a gas or steam turbine as a prime mover.
Three Phase
AC power sources that comes in one three separate “hot” power lines typically at a set number of degrees apart to produce a split phase type power.
Transfer Time
Amount of time it takes a UPS or Automatic Transfer Switch to transfer under emergency conditions or, more commonly, the time delay programmed in before either would retransfer back to its normal state.
Unbalanced Load
In a split phase, most commonly, three phase system where the load is not the same on all phases. For example, Phase A might be loaded 100 amps, Phase B loaded 50 amps and Phase C loaded 80 amps. It is generally good electrical practice to attempt to load all phases equally as much as possible but is not generally required by most modern UPS units.
UPS Rectifier
Converts incoming AC voltage to a DC voltage to either directly charge batteries or feeds a DC to DC battery charger.
Uninterruptible Power Supply (UPS)
A UPS supplies power automatically and instantly during a power outage. Commonly used in conjunction with standby generators to prevent electrical disruption in Datacenters, Computer Rooms, Switching Offices, Process Centers, Laboratories, and Medical Facilities.
The difference in electrical potential between two points of a conducting wire.
Measurement of electrical potential difference expressed in volts.
Voltage Regulator
By modulating the flow of DC to the rotor, a voltage regulator automatically maintains optimum generator voltage.
Measurement of electrical power. One watt is equal to 1 joule of energy per second.
The winding comprises all the coils of a generator.