Equipment Maintenance

Question 1

Why must unqualified or inexperienced people be extremely careful when attempting to troubleshoot or repair electrical equipment?

Answer 1

Unqualified or inexperienced person must be extremely careful when attempting to troubleshoot or repair electrical equipment because they can be seriously injured and damage costly equipment if a mistake is made
page 153

Question 2

What could happen when Machinery is not shut off locked out and tagged properly?

Answer 2

When machinery is not shut off locked out and tag properly the following accidents could occur:
Maintenance operator could be clean a pump and have it start that’s losing an arm hand or finger.
Electrical motors or controls not properly grounded could lead to possible severe shot paralysis or death.
Improper circuit such as wrong connections bypassed safety devices wrong fuses or improper wiring can cause fires or injuries due to incorrect operation of Machinery.
Page 153

Question 3

How can you determine the proper voltage and allowable current in amps for a piece of equipment?

Answer 3

The proper voltage and allowable current in amps for a piece of equipment can be determined by reading the name plate information or the instruction manual for the equipment.
Page 154

Question 4

What are two types of voltage?

Answer 4

Special types of voltage are direct current DC and alternating current AC
Page 154

Question 5

Amperage is a measurement of what?

Answer 5

Amperage is a measurement of current or electron flow and is an indication of work being done or how hard the electricity is working page 155

Question 6

How can you determine if there is voltage in a current?

Answer 6

You test for voltage by using a multimeter. Page 156

Question 7

What are some of the uses of a multimeter?

Answer 7

A multimeter can be used to test for voltage open circuit blown fuses single phasing of motors and grounds. Page 157

Question 8

What precaution should be taken before attempting to change fuses?

Answer 8

Before attempting to change fuses turn off power and check both power lines for voltage. Use a fuse puller. Page 157

Question 9

How do you test for voltage with a multimeter when the voltage is unknown?

Answer 9

If the voltage is unknown and the multimeter has different scales that are manually set always start with the highest voltage range and work down. Otherwise the multimeter could be damaged. Page 158

Question 10

What could be the cause of an amp reading different from the nameplate rating?

Answer 10

Amp readings different from the nameplate rating could be caused by low voltage, bad bearings, poor circulation, plugging or excessive load. Page 158

Question 11

How often should Motors and wines be megged?

Answer 11

Motors and wiring should be megged at least once a year. And twice a year. If possible. Page 159

Question 12

An ohmmeter is used to check the ohms of resistance in what control circuit components?

Answer 12

An ohmmeter is used to test the control circuit components such as: 
coils. 
Fuses. 
Relays. 
Resistors. 
And switches. 
Page 159

Question 13

What is the most common pump driver used in lift stations?

Answer 13

The most common pump driver used in lift stations is the AC induction motor.
Page 160

Question 14

Basic lift station maintenance procedures performed at least annually will help minimize what type of lift station failures

Answer 14

Types of lift station failures that can occur due to lack of proper maintenance include:

• Current and balances or imbalances which ultimately result in motor failure.
• Lose contacts or terminals in control and power circuits causing High Resistance contacts.
• Overheating resulting in arcing fire and electrical system damage.
• Dirty enclosures and components which allows a conducted path to build up between incoming phases causing phase to phase shorts.
• Corrosion that causes high resistance contacts with you. Page 160

Question 15

What should be done when a fuse or circuit-breaker blows or trips?

Answer 15

If a fuse or circuit-breaker blows or trips the potential source of the problem should be investigated identify and correct it.
Page 162

Question 16

What are fuses used to protect?

Answer 16

Fuses are used to protect operators main circuits Branch circuits and Equipment such as heaters and motors from excessive current. Page 162

Question 17

Why must fuses never be bypassed or jumped?

Answer 17

A fuse must never be bypassed or jumped because the fuse is the only protection the circuit has. Without it serious damage to equipment and possible injury to operators can occur. Page 162

Question 18

What are the two types of overcurrent devices that should be installed to protect the main control panel and wiring from damage due to excessive voltage or amperage?

Answer 18

Fuses and circuit breakers are overcurrent devices that should be installed to protect the main control panel and wiring from damage due to excessive voltage or amperage. Page 163

Question 19

What types of annual maintenance should be performed with regard to fuses?

Answer 19

Annual maintenance that should be performed with regard to fuses include:
Inspect all bolted connections at all fuse clips of fuse holder for signs of looseness.
Check connections for any evidence of corrosion from washer or atmosphere air pollution.
Tighten connections.
Check fuse for obvious overheating.
Inspect insulation of the conductors coming into the fuses on the line side and out of the fuses on the load side for evidence of discoloration or bubbling which would indicate overheating of the conductors. Page 163

Question 20

How does a circuit breaker work to provide protection from excessive current for equipment and conductors?

Answer 20

Circuit breakers provide protection from excessive current for equipment and conductors without the inconvenience of changing fuses.
Circuit breakers trip (open the circuit) when the circuit flow is excessive.
In a magnetic circuit breaker the current is sensed by a coil that forms and electromagnet
When the current is excessive the electromagnet activates a small armature that pulls a trip mechanism thus opening the circuit breaker.
In the thermal type of circuit breaker the current heat a bimetallic strip when heated sufficiently the strip Bends enough to allow the trip mechanism to operate. Page 163

Question 21

Motor and supervisory control systems are composed of what types of auxiliary electrical equipment?

Answer 21

The motor and supervisory control systems are composed of the auxiliary electrical equipment such as relays Transformers light panels pump control logic alarms and other electrical equipment typically found in a lift station electrical system. Page 166

Question 22

What are the three basic factors that contribute to the reliable operation of electrical systems found in lift stations?

Answer 22

The three basic factors that contribute to the reliable operation of electrical systems found in a lift stations include:
*And adequate preventive maintenance program must be implemented and maintained. *A knowledge of the system by the collection system operator even though the operator does not perform the actual maintenance.
Adherance to three principles keep it clean keep it dry keep it tight. Page 167

Question 23

What are the two types of indication motor construction typical encounter when dealing with AC induction Motors?

Answer 23

The two types of induction motor constructions that are typically encountered when dealing with AC induction Motors are:
*Squirrel cage induction motor *Wound cage induction motor. Page 167

Question 24

List the five most common causes of electrical motor failure.

Answer 24

The five most common causes of electric motor failure are: Overload (thermal) Contaminants. 
Single phasing. 
Bearing failures. 
Old age. 
Page 170

Question 25

List the three components of a insulation temperature rating.

Answer 25

``` The three components of an insulation temperature rating consist of: Ambient operating temperature. Temperature rise. Hotspot allowance. Page 170-171 ```

Question 26

How are motor starters controlled?

Answer 26

Motor starters can be either manually or automatically controlled. Page 175

Question 27

When are magnetic starters used?

Answer 27

Magnetic starters are usually used to start pumps compressors blowers and anything were automatic or remote control is desired. Page 175

Question 28

What two types of overload protection devices are used on magnetic starters?

Answer 28

The two types of overload protection devices used on magnetic starters are: A bimetallic strip that is precisely calibrated to open under higher temperature conditions to de-energize the coil. A small solder pot within the coil that melts because of the Heat and will de-energizer the system. Page 176

Question 29

How can the direction of rotation of a 3-phase motor be changed?

Answer 29

The direction of rotation of a 3-phase motor can be changed by changing any two of the power leads. Page 180

Question 30

What is the key to effective troubleshooting?

Answer 30

The key to effective troubleshooting is practical step-by-step procedures combined with a common sense approach page 183

Question 31

What are some of the steps that should be taken when troubleshooting magnetic starters?

Answer 31

``` When troubleshooting magnetic starters: Gather preliminary information. Inspect. Contacts mechanical Parts magnetic parts page 186-187 ```

Question 32

What kind of information should be recorded regarding the electrical equipment?

Answer 32

Information that should be recorded regarding electrical equipment includes every; Change. Repair. Test. Page 188

Question 33

What are some uses of pumps?

Answer 33

Pumps are used to move waste water in collection systems with a gravity system is not feasible or too costly. In the collection system there are used in lift stations were it is necessary to lift the water from a low elevation to a higher elevation. Pumps also are used in High Velocity cleaners for cleaning collection systems. They are used to dewater trenches or excavations while installing pipelines or repairing them. Automobile have oil pumps and water pumps while backhoes have hydraulic pumps. Page 192

Question 34

Why is it important to know how a pump is built?

Answer 34

If we know how pump is built it is easier to understand how to operate and maintain a pump.

Question 35

What are the main points to keep in mind regarding the lubrication of a pump

Answer 35

Keep the right amount of right lubricant in bearings at all times. Follow your pump manufacturers lubrication instructions to the letter. The main points to keep in mind are: Although too much oil will not harm sleeve bearings too much grease and anti-friction type bearings (ball or roller) will promote friction and heat The main job of grease in anti-friction bearings is to protect steel elements against corrosion not friction. Operating conditions vary so widely that no one will rule as to frequency of changing lubricant will fit all pumps. So play it safe if anything change lubricant before it is too warm or too dirty. Page 194 195

Question 36

Why is it so important to see that the pump and the motor flanges are parallel vertically and axially and that they are kept that way?

Answer 36

See that the pump and motor flanges are parallel vertically and axially and that they are kept that way. If shafts are eccentric or meeting at an angle every Revolution throws tremendous extra load and bearings are both pump and motor. Flexible couplings will not correct this condition if excessive. Checking alignment should be a regular procedure and pump maintenance. Foundations can settle on unevenly piping can change pump positions both can loosen. Misalignment is a major cause of pump and coupling wear. Page 195

Question 37

Why must horizontal suction lift piping always slope upward toward the pump?

Answer 37

Horizontal suction lift piping always slopes upward toward the pump. The upsloping prevents air pocketing in the top of the pipe we're trapped air might be drawn into the pipe and cause loss of suction. Page 195

Question 38

What is the best way to ensure that piping puts absolutely no strain on the pump casing and why is this important?

Answer 38

See that typing puts absolutely no strain on the pump casing. The weight of piping can easily ruin a pump. When the original insulation is made all piping should be in place and self-supporting before connection. Openings should meet with no Force otherwise the casing is apt to be cracked or strong enough to allow closely fitted pump parts to rub. It is a good practice to check the piping supports regularly to see that loosening or settling of the building has not put strains on the casing. Page 195 through 196

Question 39

Why should I pump never be allowed to run dry?

Answer 39

A pump should never be allowed to run dry because water acts as a lubricant between the wearing rings and the impeller. Page 196

Question 40

List three types of centrifugal pumps.

Answer 40

Three types of centrifugal pumps include: Horizontal nonclog. Vertical ball bearing. Propeller. Page 199 201

Question 41

How does a screw pump work?

Answer 41

Screw pumps consists of a screw operating at a constant speed without a housing or trough. The screw has a pitch and is set at a specific angle. When revolving the screw carries the waste water up the trough to a discharge Point. Page 202

Question 42

Under what conditions would a Pneumatic ejector be used?

Answer 42

Pneumatic ejectors are used when it is necessary to handle limited or low flows with relatively large solids. Page 203

Question 43

What type of pump is used in a high-velocity cleaner?

Answer 43

Piston Pumps are commonly used in high-velocity cleaners. Page 205

Question 44

Why are portable centifugal pumps often referred to as trash pumps?

Answer 44

Portable centrifugal pumps are often referred to as trash pumps because the water being pumped is not clean and may contain suspended solids of various sizes. Page 208

Question 45

Why should the suction hose of a portable pump have a strainer on the end?

Answer 45

The suction hose has a strainer on the end to prevent pulling rocks and debris into the pump to avoid damaging the pump or plugging the hoses or pipes. Page 209

Question 46

What precautions would you take when operating a portable pump and whether that is subject to freezing?

Answer 46

When operating a portable Pump and whether that is subject to freezing always drain the pump to prevent the freezing water from cracking the casing or binding up the pump. Remember starting the pump turn the shaft by hand to make sure it turns freely. If the impeller is frozen fast warm the pump slowly until the ice melt. Page 209

Question 47

List the advantages of a positive displacement diaphragm pump

Answer 47

Some of the advantages of a positive displacement diaphragm pump or the following: Self-priming if the suction lift is small. When primed with water it will pump with a suction lift up to 25 ft. Large particles will readily pass through the pump. Less likely to become clogged than centrifical pumps page 210

Question 48

What would you do if a diaphragm pump suddenly stops pumping and the engine either quit or keeps running and the pump Rod slips on the shaft?

Answer 48

If a diaphragm pump suddenly stops pumping remove discharge valve and clean out pump cavity. Page 210 chart

Question 49

What maintenance should be performed on a pneumatically operated diaphragm pump after use?

Answer 49

After use pneumatically operated diaphragm pumps should be flushed thoroughly to prevent dried sediment from interfering with valve operation. If the water pump had large particles in it and maybe necessary to dismantle the part to remove any remaining particles. Page 212

Question 50

How often should pump impellers be inspected for wear?

Answer 50

Pump impellers should be inspected for wear on a regular basis such as every 6 months or annually depending on pumping conditions. If grits and or other abrasive materials is being pumped inspections should be more frequent. Page 213

Question 51

How can you tell if an impeller has damage from cavitation?

Answer 51

An impeller shows cavitation damage if it has holes indentions bullet chips or cracks on the surface. Page 214

Question 52

What can happen if pump clearances are not kept in proper alignment?

Answer 52

Pump clearances are not kept in proper adjustment for pump may become plugged frequently and power requirements will increase due to lowered efficiency. Page 215

Question 53

What is the purpose of wearing rings?

Answer 53

Wearing Rings protect the impeller and pump casing from damage due to excessive wear by solids and grit. Page 215

Question 54

What causes cavitation?

Answer 54

Cavitation is caused by the pump operating at conditions different from those for which it was designed such as operating off design curve poor suction conditions high-speed air leaks into the suction in and water hammer conditions. Page 215

Question 55

How can pump shafts be protected from damage?

Answer 55

Pump shafts can be protected from damage by installation of shaft sleeves over the shaft in the area of the shaft what passes through the stuffing box. Page 216

Question 56

When should a pump shaft sleeve be repaired or replaced?

Answer 56

A pump shaft sleeve must be repaired or replaced when grooves are observed page 216

Question 57

What is the purpose of packing?

Answer 57

Packing is used to provide a seal where the shaft passes through the pump casing in order to keep air from being drawn or sucked into the pump or the water being pumped from coming out. Page 217

Question 58

What is the purpose of the Lantern ring?

Answer 58

The Lantern ring is used to allow outside water or grease to enter the packing for lubrication flushing and Cooling and to prevent air from being sucked or drawn into the pump. Page 219

Question 59

Why should a pump with a mechanical Seal never be allowed to run dry?

Answer 59

When a pump is fitted with a mechanical sleeve that must never run dry or the seal faces will be burned and ruined. Page 222

Question 60

What should be done when a mechanical seal develops a leak?

Answer 60

Mechanical seals are not supposed to have any leakage from the gland. If a leak develops the seal may require relapping or it may have to be replaced. Page 222

Question 61

What are the different types of bearings used in pumps?

Answer 61

``` The different types of bearings used in pumps include ball bearings roller bearings and sleeve bearings. Page 223 ```

Question 62

What should be done whenever a bearing failure occurs before it's expected replacement time?

Answer 62

Whatever a bearing failure occurs before it's expected replacement time the bearing should be examined to determine the cause and, if possible to eliminate the problem. Page 223

Question 63

List as many different types of bearing failures as you can remember.

Answer 63

``` The different types of bearing failures include: fatigue failure contamination Friending, False brineling, thrust failures misalignment electrical arcing lubrication failure and cam failure Page 223 ```

Question 64

What can cause contamination failure of a bearing and how can it be prevented?

Answer 64

Contamination failure of a bearing can be caused by dirty or damp surroundings or abrasive waste materials. Contamination failure of a bearing can be prevented. Where a manufacturing process involves an abbrasive by product it is essential that the bearing be properly sealed. Also clean tools dirt-free working area and clean dry hands are essential to prevention of bearing failures Carefree control of washing procedures relubrication and handling of bearings according to recommended practices will alleviate many of the problems of contamination failures. Page 226 227

Question 65

How can bearing failures from misalignment be prevented?

Answer 65

Bearing failures from misalignment can be prevented by ensuring proper alignment of pump shaft and housing. Page 235

Question 66

How can bearing lubrication failures be identified?

Answer 66

Bearing lubrication failures can be identified by Grease appearance abnormal temperature rise noise Bearing discoloration and retainer failure. Page 238

Question 67

What is the purpose of a coupling?

Answer 67

Couplings are used to connect a source of power to a shaft such as a shaft of a pump impeller. Page 242

Question 68

List four common methods of coupling a pump and driver together

Answer 68

``` Methods by which a pump or driver can be couple together include: Direct coupled. Belt driven. Flexibly shafted close coupled. Page 242 ```

Question 69

What are the functions of a flexible coupling?

Answer 69

The main functions of a flexible couplings are: To transmit power effectively and efficiently from one shaft to the other To decrease wear on shaft bearings and driven equipment. To accommodate the slight shaft misalignment that developed in service. Other functions of flexibility couplings include: To absorb shock loads and pulsations. To dampen vibrations. To accommodate load reversals. To minimize initial backlash. To provide ease of installation and maintenance

Question 70

How can you tell if coupling alignment is proper?

Answer 70

To inspect for proper coupling alignment look for the parallel and angular misalignment using a feeler gauge or a straight edge placed squarely across the rings of the coupling halves. Place the feelers at the top bottom near and far sides of the coupling Junctions. Also Place The Feelers along the edge of top and sides of the shaft. Dial indicators Also may be used. Page 242

Question 71

What do you look for when inspecting clearances between the faces of the coupling halves?

Answer 71

When inspecting clearances between the faces of the coupling halves be sure they are set so they cannot strike roll or exert a pull on either machine Page 242

Question 72

What is an advantage of driving a pump with belt?

Answer 72

An advantage of driving a pump with belts is that different speed ratios can be achieved between the motor and pump. Also the motor can be placed in a variety of positions with respect to the pump. Page 244

Question 73

Why must all belts on a pump be replaced at the same time?

Answer 73

All belts on a pump must be replaced at the same time with a match set so all belts will wear evenly. The used belt also have been stretched and will not allow proper adjustment. Page 244

Question 74

How can you determine if motor and pump sheaves are properly aligned?

Answer 74

Alignment of motor and pump sheaves can be determined by placing a straight edge between the two pulleys and making sure that both are on the same plane. Another method is to use a string pulled across both pulleys making sure that the string hit the pulley at all points. Page 244

Question 75

Why should belts and sheaves be kept clean?

Answer 75

Both belts and sheaves must be kept clean to reduce wear | Page 244

Question 76

How can you determine if a belt has the proper tightness or tension?

Answer 76

Proper belt tension is achieved when the belts have only a slight bow on the slack side of the belt drive while operating under load or when belts have a three-quarter inch movement from head pressure at the midpoint of the slack belt when the unit is off. Page 246

Question 77

What should you do when belt squeal during startup?

Answer 77

If belts squeal during startup reposition the motor to increase tension until slippage and squeal disappear page 246

Question 78

What happens when belt are adjusted too tight?

Answer 78

When belts are adjusted too tight problems can result such as bearings Heating and belt wearing excessively. Page 246

Question 79

When is flexible shafting installed?

Answer 79

Flexible shafting is installed when the pump and the driver are located relatively far apart. Page 246

Question 80

How often should universal joints be lubricated?

Answer 80

Universal joints should be lubricated every 200 hours during continuous service and every 500 hours during intermittent service. Consult the manufacturers literature for proper type of lubrication and Details. Page 246

Question 81

How can you tell if there is a bearing failure in a universal joint?

Answer 81

Failure of a bearing in a universal joint can be indicated if.: Grease does not come out all four bearings when greasing. Brown powder appears in the area of 1 bearing. Rough uneven play occurs when the yoke is moved. Page 246

Question 82

List some of the uses of a compressor in connection with operation and maintenance of a Wastewater collection system.

Answer 82

Compressors are used to activate Wastewater ejectors pump control systems (bubblers) valve operators and water pressure systems. They are also used to operate portable pneumatic tools such as jackhammers compactors air drills sandblasters tapping machines and air pumps. Page 249

Question 83

How often should the suction filter of a compressor be cleaned?

Answer 83

The frequency of cleaning a suction filter on a compressor depends on the use of the compressor and the atmosphere around it. The filter should be inspected at least monthly and cleaned or replaced every 3 to 6 months. Will frequent Inspection Cleaning and replacement are required under Dusty conditions such as operating a jackhammer on a street. Page 249

Question 84

How often should a compressor oil be changed?

Answer 84

Compressor oil should be changed at least every 3 months unless the manufacturer States differently. If there are filters in the oil system these also should be changed. Page 250

Question 85

How often should the condensate from the air receiver be drained?

Answer 85

Drain the condensate from the air receiver daily. Page 250

Question 86

What must be done before testing belt tension on compressors with your hands?

Answer 86

Before testing belt tension on a compressor with your hands make sure the compressor is locked off and tagged. Page 250

Question 87

What is the purpose of lubrication?

Answer 87

The purpose of lubrication is to reduce friction between two surfaces and to remove heat caused by friction. Page 250

Question 88

What happens to oils in service?

Answer 88

Oils in service tends to become acidic and may cause corrosion deposits sledging and other problems. Page 251

Question 89

What should be done to ensure proper lubrication of equipment?

Answer 89

To ensure proper lubrication of equipment determine the proper lubrication schedule the type of lubricant and the amount of lubricant and repair a lubrication chart. Page 251

Question 90

How can the lubrication chart or schedule be kept up-to-date?

Answer 90

To keep the lubrication chart or schedule up-to-date always record each lubrication job when complete and have the operator who did the job initial the record card. If there are failures due to the wrong or insufficient lubricant change or increase the lubrication frequency on the schedule. Also be sure to add new equipment to the schedule and remove discarded equipment from the schedule. Always keep the lubrication schedules up-to-date. Page 252

Question 91

What precautions must be taken when handling or storing oils and greases?

Answer 91

When handling or storing oils and greases some special precautions must be followed. Make sure the storage area does not create a fire hazard. Do not store lubricants near an open flame. Post "no smoking" signs outside the storage building. Wipe up spills and keep Lids tight on containers. Finally keep the storage area clean. When storing lubricants cleanliness is of utmost importance. Page 252

Question 92

What precautions must be taken before oiling or greasing equipment?

Answer 92

Before oiling or greasing equipment shut it off lock it out and tag it so it cannot start unexpectedly and injur you. Page 252

Question 93

What should be done after a lubrication job is completed?

Answer 93

After a lubrication job is completed clean up the area property store or dispose of oily rags and materials and inspect the lubricated equipment in a few hours to make sure it is not overheating or making any strange or unusual noise. Page 253