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29 Cards in this Set
- Front
- Back
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Two types of capacitors |
Start and run what |
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What does a start capacitor do? |
Help to start the motor Extend the sine wave |
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What do run capacitors do? |
They improve the efficiency of compressors |
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Primary problems with mechanical compressor failure |
Lubrication Flooding and slugging Flooded start Overheating |
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What of the main 4 issues with compressors can be disguised as a motor burnout |
Lubrication issues |
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Culprit of too much oil & causes |
Noisy unit Multiple compressor changes Someone added too much |
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Cures and what to look for ‘too much oil’ |
Signs of slugging, majority in piston area Drain oil, correct compressor issue Correct the piping & traps Use oil separator if manufacture seems necessary |
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Too little oil causes & visual |
Friction, seized components Low refrigerant / load Improper piping Frozen evap / Short cycling compressor |
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Too little oil cures |
Correct charge / low load conditions Correct install and piping Clean and defrost evap Correct short cycling of compressor |
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What is flooding |
A continuous stream of liquid to the compressor |
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Flooding cures |
Check and correct superheat |
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What is slugging? |
When a big lump of refrigerant hits the compressor at once |
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Slugging causes |
Severe overcharge (fixed metering) Rev stuck open Refrigerant and oil stuck in suction line by inlet |
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Slugging cures |
Proper superheat Correct piping |
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Flooded start is? |
When refrigerant migrates to and fills the compressor with liquid, then it starts |
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Causes for flooded start? |
Compressor colder than rest of system. Install / fix crank case heater |
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Components / uses of a start cap? |
High micro farad rating For increased starting torque Have a ceramic sheep not remain in circuit Have a bleed resistor Replacement may not exceed 130% of original voltage rating |
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Components / use of a run cap |
For run efficiency In a metal case Oil filled for internal cooling Lower microfarad rating Identified terminal for hot side (older models) May not exceed 110% of voltage rating |
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How to check windings of a motor |
Every terminal to ground Measure c to r, c to s, r to s = total C to r and c to s, c to r > c to s |
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Types of starting relays |
Current relay Potential relay Solid state relay (positive temp coefficient) Hot wire relay (thermal relay) |
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4 things about a current relay |
Senses high current, closes Opens after inrush current drops No. Contacts Cool has large diameter wire with few turns Once it closes start windings enter circuit If contacts don’t close, overloads trip eventually |
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4 things about potential relays |
Removes start winding / cap from circuit Has fine wire, many turns N.c. Contacts Relay is in parallel with start winding Cool is between 2 and 5, contacts between 1 and 5 Contacts open when motor is at 75% max rpm Position sensitive, closed by weight |
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Solid state relay facts |
No moving parts Very low resistance at start As resistance grown flow stops |
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Hot wire relay facts |
Uses a wire in series with windings, expands and contracts with current flow 2 sets of contacts 1. Takes out start windings 2. Acts as an overload |
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What does rsir stand for |
Resistance start induction run |
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What does csir stand for? |
Capacitor start induction run |
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What does cscr stand for |
Capacitor start capacitor run |
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What does psc stand for |
Permanent split capacitor |
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Which split phase motor setup has 2 separate configurations |
Csir , current relay and potential relay |
