User Guide

5
Coils used in refrigeration applications are usually encapsulated, providing
better protection against environmental extremes and longer life. In this coil
type, the magnet wire is wound in layers over a nylon bobbin. This assembly is
then completely molded or cast over all exposed portions. The most common
encapsulants used for coils are epoxy formulations.
Description
Advantages of encapsulated coils include:
Outstanding dimensional stability
Cleaner appearance
Moisture resistance
Abrasion resistance
Shock resistance
Electrical strength
Thermal dissipation
Advantages of
encapsulation
The life expectancy of a coil assembly is usually considered to be a function of
temperature. If the coil is operated within its design limits, then it will provide
many years of acceptable life. As a rule of thumb, for every 10 degrees Celsius
operation above the limiting coil temperature, the life expectancy decreases
by 50 percent.
Life expectancy and
temperature
Caution: Remove power
before disassembly
Any coil that is energized when not assembled to a valve will draw high currents,
consequently becoming very hot. Continued operation in this manner will
cause the coil to fail in a short period of time; therefore, it is important for the
service person to make certain that power is removed from the coil before
disassembling the coil from its valve.
Coils can be wound to operate on dual frequency (50 to 60 Hertz [Hz]). If such
a coil is operated on 50 Hz, it will draw more power than when used at 60 Hz.
It will also generate more heat than if used at 60 Hz.
Dual-frequency coils
Coils