Below Are Parts Of Compressors:

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The possible slight leakage of refrigerant through a shaft gland may be acceptable with a large system but would lead to early malfunction of a small circuit.

The wide use of small refrigeration systems has led to the evolution of methods of avoiding shaft seals, provided that the working fluid is compatible with the materials of electric motors and has a high dielectric strength.

The semi-hermetic or accessible-hermetic compressor has the rotor of its drive motor integral with an extended crankshaft, and the stator is fitted within an extension of the crankcase. Suction gas passes through the motor itself to remove motor waste heat.

Induction motors only can be used, with any starting switches outside the crankcase, since any sparking would lead to decomposition of the refrigerant. Electrical leads pass through ceramic or glass seals.

Small compressors will be fully hermetic, i.e. having the motor and all working parts sealed within a steel shell, and so not accessible for repair or maintenance.

The application of the full hermetic compressor is limited by the amount of cooling by the incoming cold gas, heat loss from the shell, and the possible provision of an oil cooler.

The failure of an inbuilt motor will lead to products of decomposition and serious contamination of the system, which must then be thoroughly cleaned.

Internal and external motor protection devices are fitted with the object of switching off the supply before such damage occurs.

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