Scroll Compressors
What two main intertwined parts produce compression in a scroll compressor?
What are a fixed scroll and an orbiting scroll?
In a stationary-blade rotary compressor, what component remains in constant contact with the rotating impeller?
What is a single spring-loaded stationary blade?
What substance is required in all compressors to lubricate mechanical parts and prevent wear?
What is refrigerant oil?
Which common electrical devices provide overcurrent protection for compressor motors?
What are circuit breakers or fuses?
What type of overload is embedded directly into the motor windings by the manufacturer?
What is an internal overload?
In what direction or path does the lower scroll move around the center of the fixed scroll?
What is an eccentric orbiting path?
What component in the suction line prevents high-pressure vapor and oil from flowing back into the evaporator?
What is a check valve?
What is used to cool the internal motor windings of hermetic and semi-hermetic compressors?
What is low-temperature refrigerant vapor?
Where is a thermal overload device typically mounted on a compressor?
What is to the compressor shell near the motor terminals?
What action is required by a technician if a compressor overload features a manual reset button?
What is pressing the manual reset button after conditions normalize?
How many sealed vapor pockets are typically formed between the scrolls at various stages of compression?
What are four sealed vapor pockets?
How can capacity be modulated in some scroll compressors by re-routing partially compressed vapor?
What is by opening a bypass port back to the compressor inlet?
What dangerous condition occurs if noncompressible liquid refrigerant enters the suction side of a compressor?
What is liquid slugging?
In series with which compressor motor terminal is a thermal overload wired?
What is the Common terminal?
Why might a thermal overload trip regularly even if the compressor's internal mechanics are healthy?
What is high ambient temperature or poor cooling airflow around the compressor shell?
Where does compressed high-pressure refrigerant vapor escape from the scrolls?
What is the center discharge port?
What electrical component method is used to modulate scroll compressor capacity by changing motor speed?
What is a variable speed motor (or inverter drive)?
What can happen to valves, pistons, and scrolls if liquid refrigerant enters the compression chamber?
What is severe mechanical damage or breakage?
What temperature-sensing mechanism inside many thermal overloads opens and closes electrical contacts?
What is a bimetal disc?
What system issue can cause high head pressure that leads to thermal overload tripping?
What is a blocked or dirty condenser coil?
Name two major benefits of scroll compressors over reciprocating compressors.
What are fewer moving parts, lower noise/vibration, less friction, or smooth torque?
How does briefly moving the fixed and orbiting scrolls apart modulate compressor capacity?
What is by creating gaps that allow pressure differences between pockets to equalize?
What primary issue results from allowing a compressor to run starved of oil or refrigerant cooling?
What is overheating, unlubricated metal-to-metal contact, or motor burnout?
Name four critical operating variables monitored by compressor protection devices.
What are current draw, head pressure, dome temperature, and discharge line temperature?
What harmful physical byproduct is created during unlubricated metal-to-metal contact inside a compressor?
What are small metal chips/shavings in the refrigerant loop?