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vij
06-11-2013, 02:00 PM
What is the difference in construction of HBP and LBP compressor. What will happen if I use a HBP compressor in place of LBP compressor having same displacement capacity in low pressure condition.

B G Scott
06-11-2013, 02:25 PM
Compression Ratio.
The power requirements will be selected to provide the correct drive to provide the design balance between the suction and discharge pressures and not be overloaded through the operational cycle.
If you apply the incorrect compressor you will in all probability expose the machine to overload conditions.

preeti
08-11-2013, 10:41 AM
There is a difference between LBP and HBP compressors. The difference is the motor, which is more powerfull for the HBP version.
Actually the same counts if you compare compressors for different refrigerants. From the outside a R600a compressor looks the same as an R134a compressor, but the motor of that R134a version is way more powerfull because of the difference in pressures from the refrigerants

vij
09-11-2013, 06:34 AM
I used one HBP compressor with R22 gas. The pressure on both sides was 20% below rated pressures, current drawn was 80% of the rated current. A gas accumulator was connected just before the compressor, the temperature of gas entering compressor was cooler and was varied by varying the fan speed at the evaporator but the motor kept on heating. The temperature of compressor shell remained higher in lower portion by 2 to 3˚C then upper portion continuously, the shell temperature kept on rising from 50 to 130˚C until the compressor tripped in 20 minutes. What can be the reason of motor over heating in this condition.

mikeref
09-11-2013, 08:53 AM
Depends on the application you fitted this compressor to. Compressors need to have the suction temperature of your gas as cold as possible without liquid being involved. (Sensible heat gain from evaporator exit to compressor inlet.) HBP is the right selection if you are using R22 for air-conditioning though low temperature work on R22 causes several problems.
You need to explain the application your compressor is fitted to.

rupertsilva10
28-11-2013, 08:49 AM
An HBP compressor is designed to pump a much higher volume of refrigerant, thus the valve ports are larger. This makes it less able to pull into a very deep vacuum. It is not a big difference, but there is a difference.
Since the HBP compressor is designed to pump a higher refrigerant volume, it has a little heavier motor. When run in a low temp low volume application, the more powerful motor will run closer to synchronous speed, which causes it to run hotter than it should, thus it needs a little more cooling than the LBP motor.

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