Friedrich SM21J30A4, Руководство по обслуживанию, Страница: 24 / 70

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The overload is wired in series with the common motor
terminal. The overload senses both major amperage and
compressor temperature. High motor temperature or
amperage heats the disc causing it to open and break the
circuit to the common motor terminal.
1. With no power to unit, remove the leads from the com-
pressor terminals.
2. Using an ohmmeter, test continuity between terminals
C-S and C-R. If not continuous, the compressor over-
load is open and the compressor must be replaced.
FAN MOTOR
A single phase permanent split capacitor motor is used
to drive the evaporator blower and condenser fan. A
self-resetting overload is located inside the motor to
protect against high temperature and high amperage
conditions. (See Figure 5)
CHECKING THE INTERNAL OVERLOAD
(See Figure 4)
Heat generated within the compressor shell is usually due to:
1. High amperage.
2. Low refrigerant charge.
3. Frequent recycling.
4. Dirty condenser.
TERMINAL OVERLOAD - TEST
(Compressor - External Type)
1. Remove overload.
2. Allow time for overload to reset before attempting to
test.
3. Apply ohmmeter probes to terminals on overload wires.
There should be continuity through the overload.
TERMINAL OVERLOAD (Internal)
Some model compressors are equipped with an internal
overload. The overload is embedded in the motor windings to
sense the winding temperature and/or current draw. The
overload is connected in series with the common motor
terminal.
Should the internal temperature and/or current draw become
excessive, the contacts in the overload will open, turning off
the compressor. The overload will automatically reset, but may
require several hours before the heat is dissipated.
External Overload
Internal Overload
Figure 3
Figure 4