waste water ch15

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  1. Repair costs for poorly maintained equipment usually exceed the cost of maintenance
  2. Chlorine gas leaks around chlorinators or containers ofchlorine will cause corrosion of equipment
  3. Misalignment is a major cause of pump and coupling wear
  4. When lubricating motors, too much grease may cause bearing trouble or damage the winding
  5. If a centrifugal pump attempts to start while the pump,motor, and shafting are rotating in the opposite direction,very serious damage can occur to the pumping equipment.
  6. Meggers work only when the circuit breaker is closed
  7. When megging a motor, if a low reading is observed, themotor winding insulation is in good condition
  8. A rod driven into dry ground is very effective as a ground.
  9. Complete, up-to-date equipment records will enable you toevaluate the reliabiliry of your equipment and will providethe basis for a realistic preventive maintenance program
  10. Always lubricate underwater chains that operate in contactwith considerable grit
  11. Problems with scum lines are more frequent and more severe in colder weather when grease tends to harden quickly.
  12. The performance of a treatment facility can be evaluated orcompared with other plants without flow measurements
  13. Each individual sensing meter will have its own maintenance requirements.
  14. Meters should be calibrated and performance cross checked regularly to ensure accurate and reliable meter readings under all conditions at all times
  15. How can operators keep equipment warranties in force?
    By good records
  16. Why should operators schedule inspections and maintenance of tanks and channels during periods of low flow?
    To minimize the load on other plant treatment units
  17. Why are well-groomed and neat plant grounds important?
    Because many people judge the ability of the operatorand the plant performance on the basis of the appearanceof the plant
  18. Why should a pump never be allowed to run dry?
    Because water is a lubricant berween rings and impeller
  19. How is a pump primed?
    By completely filling the pump with water
  20. What is a nameplate?
    A durable, metal plate found on equipment that listscritical operating conditions for the equipment
  21. What is a watt? A watt is
    A measure of power units used to rate electrical machinesor motors or to indicate power in an electric circuit
  22. What can a multimeter be used to measure?
    Voltage, current, and resistance
  23. Why are voltage readings with a multimeter important?
    Because they determine how you connect motor leads,relays, and transformers
  24. What is "ground"?
    An expression representing an electrical connection to earth or a large conductor that is at the earth's potentialor neutral voltage
  25. Why is voltage imbalance a problem in pump stations?
    Because even relatively slight variations can greatly increase the motor operating temperatures and burn outthe insulation
  26. What is a cross connection?
    A connection berween drinking (potable) water and an unapproved water supply
  27. Gate valves require which common maintenance
    Oiling, tightening, and replacing the stem stuffing boxpacking
  28. Why must moisture be removed from the atmosphere in pump stations?
    To prevent malfunctions due to corrosion and oxidation
  29. What do flow measurement controller instruments do?
    Compare received signals with other values and send corrective or adjusting signals when necessary
  30. What is the single most important item to be considered in sensor maintenance?
    Good house keeping
  31. A successful plant maintenance program will cover which items?
    • Mechanical equipment
    • Moving equipment
    • Plant buildings and structure
    • Plant ground
  32. What are some of the advantages of mechanical seals?
    • Continual adjusting, cleaning, or repacking is not required
    • Low initial cost
    • The possibility of flooding a lift station because a pump has thrown its packing is eliminated
    • They last from three to four years without having to touch them
    • Usually, there is not any damage to the shaft sleeve whenthey need replacing
  33. Which items appearing at the brushes indicate unsatisfactory performance of AC slip rings and brushes?
    • Chattering and noisy brushes
    • Glowing at the brush face
    • Pitting of the brush face
    • Rapid brush wear
    • Sparking
  34. Which symptoms indicate pump operating troubles?
    • Noisy pump
    • Pump will not start
    • Reduced rate of discharge
  35. Which items could cause a pump to have a reduced rate of discharge?
    • Air leaks in the suction line or packing box
    • Discharge head is too high
    • Impeller is clogged
    • Improper wiring
    • Mixture of air in the wastewater
  36. In maintaining the various electrical equipment used in waste water collection and treatment facilities, which possible serious accidents could occur if machinery is not shut off, locked out, and properly tagged as required by OSHA?
    • Electrical motors or controls not properly grounded could lead to possible severe shock, paralysis, or death
    • Improper circuits created by mistakes, such as wrong connections, bypassed safety devices, wrong fuses, or improper wire, can cause fires or injuries due to incorrect operation of machinery
    • Maintenance operator could be cleaning a pump andhave it start, thus losing an arm, hand, or finger
  37. Which tasks should be included during the inspection of pump station electrical equipment?
    • A thorough examination
    • Operational checks and tests
    • Replacement of worn and expendable parts
  38. Which items are pump station electrical equipment protective devices?
    • Circuit breakers
    • Circuit overload devices
    • Fuses
    • Grounds
    • Motor overload devices
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waste water ch15
florida waste water class c exam
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