The accumulator is located inside the refrigeration cabinet and acts as a safety device. As a safety device it prevents the flow of liquid refrigerant into the suction line and the compressor. This is because liquid refrigerant causes considerable knocking and damage to the compressor. Figure 14-24 shows the location of an accumulator in a system.

SINGLE-PHASE HERMETIC MOTORS

Basically, there are four types of single-phase motors used in hermetic assemblies: the split- phase; the capacitor-start, induction-run; the capacitor-start, capacitor-run; and the permanent split-phase. Each motor is discussed in this section.

SPLIT-PHASE

The split-phase motor is used generally on condensing units of 1/10-, 1/6-, and 1/4-horsepower

Figure 14-24. - Accumulator location.

Figure 14-25. - Schematic wiring diagram of a split-phase motor circuit.

capillary tube systems. It has a low starting torque and contains both a starting winding and a running winding. A disconnect device is required for the starting winding when the motor reaches sufficient speed to operate on the running winding. Figure 14-25 is a schematic wiring diagram of a split-phase motor circuit.

CAPACITOR-START, INDUCTION-RUN

This motor is similar to the split-phase type except that a starting capacitor is connected in series with the starting winding to provide higher starting torque. Figure 14-26 is a schematic diagram illustrating this type of motor. A device is also required to disconnect the starting winding when the motor reaches rated speed. This motor is commonly used on commercial systems up to three-fourths horsepower.

CAPACITOR-START, CAPACITOR-RUN

Two capacitors are used with the capacitor- start, capacitor-run motor: a starting capacitor and a running capacitor. The capacitors are in parallel with each other and in series with the starting winding. Figure 14-27 is a schematic diagram illustrating this type of motor circuit. The two capacitors turn the motor power surges into two-phase power when the motor is started. At approximately two-thirds rated speed, the starting capacitor part of the circuit is disconnected by a start relay device. Only the running capacitor remains in the circuit. This type of motor has a

Figure 14-26. - Schematic wiring diagram of a capacitor-start induction-run motor.