GLOSSARY
Field Pole
Part of stator of motor which concentrates magnetic field of field winding.
Filter
Device for removing small particles from a fluid.
Flame Test for Leaks
Tool which is principally a torch and when an air-refrigerant mixture is fed to
flame, this flame will change color in presence of heated copper.
Gas
Vapor phase or state of a substance.
Gauge Manifold
A device constructed to hold compound and high pressure gauges containing
hand valves to con-trol flow.
Gauge, Vacuum
Instrument used to measure pressures below atmospheric pressure.
Halide Refrigerants
Family of refrigerants containing halogen chemicals.
Halide Torch
Type of torch used to detect halogen refrigerant leaks.
Head Pressure
Pressure which exists in condensing side of refrigerating system.
Head Pressure Control
Pressure operated control which opens electrical circuit if high side pressure
becomes excessive.
Head, Static
Pressure of fluid expressed in terms of height of column of the fluid, such as
water or mercury.
Head, Velocity
In flowing fluid, height of fluid equivalent to its velocity pressure
Heat
Invisible energy (except high intensity infra-red) caused by the motion of
molecules within any substance or matter. Will always travel from warm/hot to
cold, via either or a combination of conduction, convection or radiation.
Materials which resist flow or transfer of heat are called insulators, or insulation.
Heat Exchanger
A device for the transfer of heat energy from the source to the conveying
medium, with the latter often being air or water. Most common combinations are:
Refrigerant to air or refrigerant to water (DX), water to air (hydronic), steam to
air, steam to water.
Humidity
The total amount of moisture in air. Relative humidity (RH), is the amount of
moisture in air, relative to its total capability based upon its temperature
(dewpoint). Moisture will condense on surfaces which are below this dewpoint.
Induction Motor
An AC motor which operates on principle of rotating magnetic field. Rotor has
no electrical con-nection, but receives electrical energy by transformer action
from field windings.
Insulation
Any material or substance which has the ability to retard the flow or transfer of
heat.
Joule
Thomson Effect-Change in temperature of a gas on expansion through a porous
plug from a high pressure to a lower pressure.
Junction Box
Group of electrical terminals housed in protective box or container.
Kilowatt
Unit of electrical power, equal to 1000 watts.
Latent Heat
Heat energy absorbed in process of changing form of substance (melting,
vaporization, fusion) with-out change in temperature or pressure. Also referred
to as "hidden" heat.
Leak Detector
Device or instrument such as a halide torch, an electronic sniffer; or soap
solution used to detect leaks.
Limit Control
Control used to open or close electrical circuits as temperature or pressure
limits are reached.
Manifold, Service
A device equipped with gauges and manual valves, used by serviceman to
service refrigerating systems.
