The flashcards below were created by user
tattoo904
on FreezingBlue Flashcards.
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Repair costs for poorly maintained equipment usually exceed the cost of maintenance
True
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Chlorine gas leaks around chlorinators or containers ofchlorine will cause corrosion of equipment
True
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Misalignment is a major cause of pump and coupling wear
True
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When lubricating motors, too much grease may cause bearing trouble or damage the winding
True
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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.
True
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Meggers work only when the circuit breaker is closed
True
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When megging a motor, if a low reading is observed, themotor winding insulation is in good condition
False
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A rod driven into dry ground is very effective as a ground.
False
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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
True
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Always lubricate underwater chains that operate in contactwith considerable grit
False
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Problems with scum lines are more frequent and more severe in colder weather when grease tends to harden quickly.
True
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The performance of a treatment facility can be evaluated orcompared with other plants without flow measurements
False
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Each individual sensing meter will have its own maintenance requirements.
True
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Meters should be calibrated and performance cross checked regularly to ensure accurate and reliable meter readings under all conditions at all times
True
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How can operators keep equipment warranties in force?
By good records
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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
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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
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Why should a pump never be allowed to run dry?
Because water is a lubricant berween rings and impeller
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How is a pump primed?
By completely filling the pump with water
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What is a nameplate?
A durable, metal plate found on equipment that listscritical operating conditions for the equipment
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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
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What can a multimeter be used to measure?
Voltage, current, and resistance
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Why are voltage readings with a multimeter important?
Because they determine how you connect motor leads,relays, and transformers
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What is "ground"?
An expression representing an electrical connection to earth or a large conductor that is at the earth's potentialor neutral voltage
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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
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What is a cross connection?
A connection berween drinking (potable) water and an unapproved water supply
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Gate valves require which common maintenance
Oiling, tightening, and replacing the stem stuffing boxpacking
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Why must moisture be removed from the atmosphere in pump stations?
To prevent malfunctions due to corrosion and oxidation
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What do flow measurement controller instruments do?
Compare received signals with other values and send corrective or adjusting signals when necessary
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What is the single most important item to be considered in sensor maintenance?
Good house keeping
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A successful plant maintenance program will cover which items?
- Mechanical equipment
- Moving equipment
- Plant buildings and structure
- Plant ground
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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
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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
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Which symptoms indicate pump operating troubles?
- Noisy pump
- Pump will not start
- Reduced rate of discharge
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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
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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
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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
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Which items are pump station electrical equipment protective devices?
- Circuit breakers
- Circuit overload devices
- Fuses
- Grounds
- Motor overload devices
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