5.RRB ALP CBT2 RAC Question bank

RAC

High pressure cut off is used to:

• Cut off power supply to condenser fan motor if pressure increases beyond the preset value
• Cut off power supply to compressor motor if pressure increases beyond the present value
• Cut off power supply to evaporator fan motor if pressure increases beyond the preset value
• None of the above

The slip in case of three phase induction motor is in the range of

• 0.5% to 5%
• 2% to 10%
• 10% to 15%
• 15% to 20%

High starting torque induction motors for compressor are use with:

• Capillary tube
• Condenser
• Float valves
• None of these

The relationship between rotor speed ‘N’, frequency ‘f’ and no. of poles ‘P’ is given by the relation-

• $$N = \frac{120f}{P}$$
• $$f = \frac{120f}{P}$$
• PN = 120 f/P
• $$N = \frac{120P}{f}$$