High Efficiency Compressor, Electric Components And Circuits - Sunbeam 20060328 Service Manual

HIGH EFFICIENCY COMPRESSOR, ELECTRIC COMPONENTS AND CIRCUITS

The high efficiency compressors of the new series are equipped with totally new electric components consisting in a PTC
1
relay , a thermally operated overload protector and a run capacitor.
Solid State Relay - See figures B3 and B4
The solid-state relay has no mobile parts. It is a PTC resistor mounted on a plastic box with the proper terminals.
The PTC self – heater resistor used in the solid-state relay has a particular characteristic: it changes from a low
resistance to a high resistance very abruptly, thus serving as connection or disconnection switch (switch on/off).
The solid-state relay is directly plugged to the compressors start and run terminals. The relay's terminals 1, 2 and 5 are
connected inside it, as well as terminals 3 and 6. The run capacitor is connected to the relay's terminals 2 and 3, so that
it is connected in parallel with the PTC resistor. See figure B3.
The voltage supply connection is made through the relay's terminal 1 and through the overload protector as indicated in
figure B3.
To verify the relay:
1. Disconnect the refrigerator's feed electric cable.
2. Remove the relay cap, disconnect the three (3) wires and take the relay away from the compressor terminals.
3. Measure resistance between the terminals 2 and 3 with an ohmmeter. Resistance should 3 to 12 ohms, at normal
room temperature. A relay in short circuit will give a "0" resistance reading. An open relay will show a very high or
infinity resistance.
Overload protector - See figures B3 and B4.
The overload protector operation is totally thermal. It opens with a heat or current surplus. Different from the previous
protectors, the internal bimetal is not auto – heatable, and is not integrated to the electric circuit. The protector has a
small integral coil heater connected in series with the compressor start and run windings.
The overload protector is plugged directly in the compressor's common terminal.
1 The PTCR designation (Positive Temperature Coefficient Resistor) defines a resistor whose resistance increases with its
temperature. Generally, "PTCR" is shortened "PTC".
L1
Overload
Start
S
Run
C M
Motor comp.
Figure B3 – Electric Circuit
Run capacitor
6 3
2
5 1
PTC relay
N
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