Generator Glossary

Have you ever asked how does a generator work? Spend a few minutes with our glossary of generator terms.

Curious about the parts and principles behind how generators work? Check out this information and learn more about electric generators and the parts that come together to make them work.

Click the term below to read the definition.


Air filter
Alternating current (AC)
Battery charging circuit fuse
Cast iron sleeve
Circuit breaker
Continuous load
Cranking battery
Cranking battery charger
Direct current (DC)
Duplex receptacle
Electronic ignition
Fuel regulator/lockoff solenoids
Full power
Full pressure lubrication
Hour meter
Idle control
Lamp test switch
Low oil shutdown
Main line circuit breaker
Mode switch
Ohm's Law
Oil drain valve
Oil fill plug
Oil level dipstick
Rated power
Service access panels
Short circuit
Single phase
Spark arrester
Spin on oil filter
Surge power
Three phase
Transfer switch
Universal Motor
Utility line
Vibration isolators

Air filter - Filters the intake air to remove any contaminants before it enters the engine.


Alternating current (AC) - Refers to the form in which electricity is delivered to your home. AC is voltage that increases to a maximum positive (+) and falls back to zero and then continues to a maximum negative (-) and back to zero. This cycle is repeated 60 times for 60 hertz AC power.


Amperage - The strength of an electric current, measured in amperes.


Amp - A measure of electric current flow. One ampere (amp) will flow when one volt is applied across a resistance of one ohm.



Battery charging circuit fuse - Protects the engine-mounted battery charging circuit against damage from electrical faults.



Cast iron sleeve - A cylinder cast into the engine to extend its life by producing a harder surface between the aluminum engine block and steel piston rings.


Circuit breaker - A thermal switch that turns off if too much current is passing through it. All receptacles on generators are circuit-breaker protected.


Continuous load - The wattage load the generator is capable of maintaining for an extended time, assuming that the engine has been maintained.


Cranking battery - Supplies power to start engine and keep control panel active.


Cranking battery charger - Maintains cranking battery at proper level during periods of inactivity to ensure reliable, consistent starting.


C.S.A. - Canadian Standards Association. Products that have this marking have been manufactured, tested and inspected to standards that are set by C.S.A.



Direct current (DC) - An electric current flowing in one direction only, such as from a battery to an appliance.


Duplex receptacle - Two 120-volt receptacles tied together, similar to the outlets you have in your house.



Electronic ignition - A solid-state ignition system with no moving parts, ensuring reliable timing or firing to the spark plug.


Endbell - The end cap of the generator section. It houses the brushes, rotor bearing and, in some cases, receptacles.



Frequency - The number of vibrations or cycles per unit of time. More specifically, the numbers of cycles per second of analternating current. See hertz.


Fuel regulator/lockoff solenoids - Controls fuel flow to home standby engine.


Full power - Denotes that the rated power of the generator can be drawn from a particular branch circuit.


Full pressure lubrication - A feature found on premium engines, utilizing an oil pump and filter to supply oil directly to the internal components of the engine, increasing the engine's life.



Generator - A general name for a device for converting mechanical energy into electrical energy. The electrical energy may be direct current (DC) or alternating current (AC). An AC generator may be called an alternator.


GFCI - Ground fault circuit interrupter. An electrical device designed to prevent severe or fatal electric shocks by monitoring current flow in a circuit, to sense any loss of current. If the current flowing through the circuit differs by a small amount from that returning, the GFCI quickly switches off power to that circuit.


Ground - A connection, either intentional or accidental, between an electric circuit and the earth or some conducting body serving in place of the earth. In power circuits, a ground is done intentionally to protect people from the effects of faulty insulation on electrically powered equipment.


Hertz - A unit representing one cycle per second.


Hour meter - Tracks the hours of actual operations on a home standby generator.

Idle control - A device that reduces engine speed when a generator set is not being operated under load. An idler conserves fuel, reduces the noise and saves wear and tear on the engine.

Lamp test switch - Checks for function of all indicator lights on the control panel.


Low oil shutdown - A feature designed to shut off the engine if it runs low on oil, preventing serious damage or failure.



Main line circuit breaker - Protects your generator and connected loads from electrical faults. Used to isolate output power from operating generator.


Mode switch - Used to set the operating state of the generator.



Ohm - Unit of electrical resistance. One volt will cause a current on one ampere to flow through a resistance of one ohm.


Ohm's Law - States that the intensity (amperage) of an electrical current is directly proportional to the electromotive force (voltage) and inversely proportional to the resistance (ohms). (Amps = Volts/Ohms) or (1 = E/R). Also displayed as Watts = volts x amps



OHV - Overhead valve. An engine design with the valves placed above the piston in the head, instead of to the side of the piston in the engine block.



Oil drain valve - Quick-turn ball valve with extended drain hose to speed up maintenance and eliminate mess.


Oil fill plug - Covers opening where you can add fresh engine oil as required.


Oil level dipstick - Dipstick for checking for proper engine lubricating oil level.


Phase - The number of complete voltage and/or current sine waves generated per 360 electrical degrees. Each phase requires a complete set of windings.



Rated power - The net electric output a generator can provide continuously when functioning as designed.


Rotor - The rotating element of a motor or generator.


RPM – Revolutions per minute. A unit of measure of engine speed.



Service access panels - Provides access to areas where service is required on home standby units.


Short circuit - An unintentional electrical contact between the current-carrying outputs resulting in the passage of current through an undesirable path.


Single phase - A single-phase alternating current system has a single voltage in which voltage reversals occur at the same time and are of the same alternating polarity through the system.


Spark arrester - A screen that covers the outlet of the muffler to stop sparks from exiting. Spark arresters are required for use in national parks and the State of California.


Spin on oil filter -Replaceable, disposable filter to remove contaminants from engine oil to prolong engine life.


Stator - The stationary part of a generator or motor.


Surge power - The load, in excess of rated load, that the generator set is capable of delivering for a specified period of time. It should be recognized that the voltage frequency and operating temperatures might differ from normal rated values.



Three phase - Three complete, separate sine waves spaced 120 electrical degrees apart.



Transfer switch - A device which will switch a load from the main utility power source to a standby power source.


Twistlock - A receptacle or plug that has a mechanism for locking it in place to prevent accidental removal.



U.L.-Underwriters Laboratory. Indicates that the products that have this marking have been manufactured, tested, and inspected to standards that are set by U.L.


Universal Motor -An electrical motor which can be used on either AC or DC supply.


Utility line -The wire provided and owned by a utility company which can carry a power supply.


Vibration isolators -Rubber pads mounted between the engine/stator and the frame of the generator. They are designed to minimize the vibrations produced by the engine.



Volt - The unit of electromotive force. That electromotive force which, when steadily applied to a conductor whose resistance is one ohm, will produce a current of one ampere.


Voltage - Electrical potential or potential difference expressed in volts.



Watt - Unit of electric power. In direct current, watts = volts x amperes. In alternating current, watt = effective amps x power factor x a constant dependent on the number of phases (1,000 watts = 1 kilowatt).


Winding - All the coils of a generator. Stator winding consists of a number of stator coils and their interconnections. Rotor windings consist of all windings and connections of the rotor poles.



Looking for more information about how generators work? Please e-mail our generator experts or call 855-436-4636, and we'll be happy to help answer any questions you might have.

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