testing

1. By
A.SRINIVAS REDDY (16-301)
A.PARSHURAM (16-302)
P.DINESH (16-316)

2.  Refrigeration: Refrigeration is a process of removing heat from
a low-temperature reservoir and transferring it to a high-
temperature reservoir.
 Air Conditioning: Air conditioning is the process of removing
heat and moisture from the interior of an occupied space, to
improve the comfort of occupants. Air conditioning can be used in
both domestic and commercial environments.
 Refrigeration may be defined as lowering the temperature of an
enclosed space by removing heat from that space and transferring
it elsewhere. A device that performs this function may also be
called an air conditioner, refrigerator, air source heat
pump, geothermal heat pump or chiller (heat pump).

3.  Refrigerator & air conditioner is mainly work on Vapor-
compression refrigeration system (VCRS) Cycle.
 Working of VCRS:

4. Process on VCRS
 Compression process(1-2): In this process the refrigerant get
compressed on compressor &sends to condenser & the
temperature , pressure of refrigerant will be increased.
 Condensation process(2-3): In this process the compressed
refrigerant enters into condenser. Where the refrigerant gets
condensed to liquid.
 Expansion process(3-4): In this process after condensation the
refrigerant enter into expansion valve. There the liquid
refrigerant gets expanded & formed in the form of semi- liquid
form.
 Evaporation process: In this process the expanded semi- liquid
refrigerant enters into evaporator . There the refrigerant
observed from the objects & vaporized.

5. Various parts of VCRS:
 Compressor
 Condenser
 Expansion valve
 Evaporator

6.  A compressor is a mechanical device that increases
the pressure of a gas by reducing its volume. An air
compressor is a specific type of gas compressor.

8. Types of compressors:
 compressors mainly classified as two types
1) positive displacement compressors
2) Dynamic compressor
Positive displacement compressor are sub divided into
two types
i. Rotary compressors
ii. Reciprocating compressors
Dynamic compressors are divided indo two types
i. Centrifugal compressors
ii. Axial compressors

9.  Rotary type compressors are classified as 3 types
i. vane type compressors
ii. screw compressors
iii. scroll compressor
Vane type compressor scroll type compressor screw type compressor

13.  TESTING OF COMPRESSORS:-
 To find out the CSR of the compressor use
Multimeter and also one can find out the CSR
(common, Start & Run) of the compressor by Test
lamp.
 First switch off the system and remove the
compressor terminal or cover.First insert the probe
of a multimeter in a common point and second
probe in ohms and set the multimeter in the
buzzer direction

14.  Alternatively touch the probe of a multimeter in
the two terminals out of the three terminals of
compressor and record the reading. By this
reading one can easily find out the CSR of the
compressor.
 The highest reading will be the “Start” winding
 The medium reading (second highest) will be the
“Run” winding
 The lowest reading will be the “Common” winding

15.  FAULT FINDING IN COMPRESSORS:-
 Unexpected sounds from compressors
knocking,grinding etc.