NEIEP Generator Maintenance and Repair (440) Practice Test

These questions are part of the practice quiz. Start practicing

• After inserting a new brush, how should the end of the brush be seated to the commutator?
• Many elevator companies no longer use which type of solvents because of health risks and fire hazards?
• Why is bearing lubrication and oil level monitoring included in routine generator maintenance?
• Which issue results from such bar conditions and leads to fractured brushes?
• What polarization index is used for in insulation testing?
• What is the purpose of a ground fault protector in generator systems?
• A sleeve bearing wears quietly and allows the armature to _____, reducing clearances.
• A ball bearing designed to carry radial loads, such as in a motor or MG set, will not last long if subjected to ________ loads.
• How do you verify proper phase rotation when wiring a generator to a bus?
• Which describes a shielded bearing when over-lubrication leads to failure?
• What is the correct gap range for MG sets and DC hoist motors?
• When performing voltage regulation stability tests on a generator under load, what is commonly used to apply the test load?
• In elevator speed regulation, what adjustment modifies the response time of acceleration or slowdown?
• Such conditions cause what issue on commutator bars, leading to fractured brushes?
• The bearing on which end of a DC hoist motor cannot be inspected without removing it from the bedplate?
• In insulation testing, tan delta is a measure of what?
• What is the purpose of oil sampling and analysis in generator maintenance?
• Whenever possible, it is best to ______ or ______ out these hazards.
• If peak current remains elevated after adjustments, what should be checked?
• Using a brush grade unsuitable for the machine and duty can lead to which wear pattern?
• During peak current tests, which condition indicates a problem with control circuitry?
• Before energizing after maintenance, guards should be ______.
• What does the open-circuit (no-load) test reveal about a generator?
• Conductive particles washed into these spaces will eventually ______ ___, requiring removal of the armature for repairs.
• What is the recommended action if you suspect a coolant leak in the cooling system?
• Which component's rattling serves as a telltale sign that sleeve bearing needs lubrication?
• What is a common indication of winding overheating in a generator’s insulation system?
• In winding insulation analysis, which sign indicates overheating may have occurred?
• How is voltage regulation stability tested under load?
• Bar Edge Burning is a fault in a commutator. Which of the following describes a related condition?
• The mica insulation between commutator bars should be kept below the surface. This statement describes what relationship?
• The ___________ must be mechanically true, the unit in good balance, and the ________ in good shape and properly adjusted
• A key action to ensure safety during lockout/tagout is testing and verifying the circuit to ensure it is actually ______.
• Besides Normal Wear / Loosening, which is listed as a possible cause of high mica?
• The relief plug _______ be removed from the bearing housing.
• The other source of friction is the bearings supporting the _________ _____.
• The surface of the commutator is ______.
• There is no way to add lubricant to a _______ bearing.
• How should you perform a safe starter/stop sequence for a generator?
• Which parameter does the short-circuit test determine?
• Which condition can cause brushes to stick in their holder?
• Which of the following is a common method to manage moisture in a generator enclosure?
• Which condition most commonly causes streaking on a commutator?
• In rotating machines, what type of bearings are most commonly used?
• What is the purpose of oil analysis in generator maintenance?
• What is a standard method to verify mechanical alignment during installation and maintenance?
• Which of the following is listed as a possible cause of high mica besides Normal Wear / Loosening?
• Which issues can result from misaligned couplings in a generator set?
• What happens to the armature clearance as the sleeve bearing wears?
• Misaligned couplings primarily cause which of the following issues?
• What does a "brown-out" or reduced voltage indicate in a generator under load?
• If peak current is higher than the specified multiple, what should you check?
• Conductive emery particles lodged between commutator bars can cause which electrical fault?
• What type of abrasive paper should be used to seat the brush to avoid conductive emery particles causing short circuits?
• What is the purpose of the synchronizing check and which instruments are used?
• Sometimes a ________ adjustment to acceleration or slowdown will help.
• Which maintenance technology is most effective for detecting winding hot spots before insulation damage occurs?
• What practice supports traceability and regulatory compliance in generator maintenance?
• Lockout procedures commonly lock the energy isolating device using which component?
• When working with ________/___________, it is essential to replace all covers or guards before energizing the equipment.
• What is the standard symbol for protective earth grounding and where is it used?
• If the commutator assembly loosens, what pushes the mica outward?
• What is the significance of a proper stator-to-ground insulation test?
• Excessive heat can cause a commutator to become what, or out of round?
• Insufficient brush spring pressure creates an increase in what at the carbon-to-copper junction?
• What should be used as a last line of defense?
• Which bearing type is required for angular loads that may cause misalignment?
• A condition called ________ __________ develops on the outer surface of the inner and/or outer bearing race. A tight fit on the shaft and in the housing will prevent this from happening.
• Which condition leads to excessive brush wear?
• Which are typical indicators that cooling system maintenance is due?
• When brush spring pressure is too what, the brushes can arc excessively due to the poor electrical contact?
• During synchronization, which instrument is commonly used to visually compare the rotor position with the bus voltage to decide when to close the breaker?
• If insulation resistance trends downward over time in a generator, what is the recommended action?
• How does a brushless excitation system supply DC to the main field without brushes?
• Most rotating machines are equipped with ____ ________.
• Brush pressure that is too what is the single most common cause of commutator problems?
• In vibration analysis, which finding indicates a bearing fault such as a ball bearing fault?
• Protective enclosures around a generator primarily ensure which safety aspects?
• How can thermography assist in generator maintenance?
• Usually, the only friction present in a DC machine is from the _________ and ________.
• What is the maximum temperature to heat a bearing?
• Which tool is used to drive a bearing onto a shaft without damaging the inner race?
• An excess of grease can cause a ball or roller bearing to _________.
• If a shielded bearing is over-lubricated or excessive pressure, the shield can be pushed against the balls. This is called a ______ shield, and the bearing will soon fail.
• The _________ ___ must include the name or names of persons who have secured their locks to the hasp, their contact information, and the date and time when the lockout took place.
• ________ losses are present in all rotating machines. Even brushes riding on the commutator are a source of ________.
• Petroleum-based solvents pose which hazards that caused many elevator companies to stop using them?
• During elevator motion, peak current should not exceed how many times the nameplate rating at full load?
• What is the primary function of the Automatic Voltage Regulator (AVR) in a synchronous generator?
• In leveling, which condition can warp and raise commutator bars?
• How can you detect a phase-to-phase short in a three-phase stator during testing?
• What is the effect of a shorted turn in a stator winding?
• Why is oil cleanliness critical for generator bearings?
• A tight fit on the shaft and in the housing will prevent this from happening.
• Brushes require a running-in period before they operate at their best. What is the term for this period?
• A worker who is in or may be in proximity to the work area is considered an __________ employee.
• If you must adjust generator __________, always work with the series field.
• How is reverse power protection typically applied in a generator system?
• Which description best summarizes compounding adjustments?
• Liquid solvent can carry particles deep into hidden recesses of a DC generator or motor. This is especially true of the spaces around which risers?
• Why is moisture control important in a generator enclosure, and what is a common method to manage it?
• Arc flash temperatures can reach as high as about ______ degrees Fahrenheit.
• Which finding on commutator bars can cause brush chatter?
• Which symptom most strongly indicates a loose or failing bearing in a generator?
• Carbon brushes are ______.
• Which of the following is a precise method to verify shaft alignment?
• What is the recommended practice when performing insulation resistance tests on energized equipment?
• The personal lock of affected employees must be secured to the ______.
• In a DC machine, which components are typically the source of mechanical friction?
• When performing generator compounding or field adjustments, which practice is recommended?
• What diagnostic test assesses insulation quality by measuring capacitance and dissipation factor?
• What is the role of a governor in generator operation?
• Too ______ pressure causes poor brush contact and unnecessary sparking, and too _____ pressure will cause excessive brush wear.
• When performing compounding adjustments on a generator, you should work with which field?
• Never heat a bearing above ___°C or ___°F.
• What is the main purpose of maintaining proper generator cooling?
• What does differential protection monitor in a generator?
• Why is it important to verify phase rotation before closing the breaker on a generator connected to a bus?
• Brush spacing (also called __________) can be checked by wrapping a long strip of paper around the commutator under the brushes
• For proper commutation and brush life, the mica insulation between commutator bars should be _____ ___ _______.
• Liquid solvent ________ ___ be applied to a commutator.
• How would you identify a loose connection in a generator terminal box?
• Light electrical load causes commutator ______.
• Under heavy operating temperatures, how does commutator trueness change?
• Which three mounting angles are considered for brush alignment?
• The continual friction of the brushes against the _________ _____________ wears the brushes down and tends to force them out of alignment, which causes trouble in commutation.
• What is the purpose of protective barriers or enclosures around a generator?
• ___ _____ is a short circuit that bridges one live conductor to another or to ground.
• During light load maintenance, which action could help reduce commutator threading?
• How can aging insulation between turns be detected?
• The lockout tag should include which information?
• Use a ______-____ _______ ______when force is required to drive it on a shaft. The ______-____ _______ ______ puts the driving force against the inner race, where it cannot do damage.
• Which protection scheme trips a generator if there is a loss of excitation?
• What does the short-circuit test reveal about a generator?
• Grooving on a commutator is caused by which factor?
• A radial load applies a force at __° to the centerline of the shaft.
• For angular loads, special bearings known as ____-________ bearings are required.
• If a resistance measurement in a generator terminal box shows a high reading, what is this most likely to indicate?
• What term describes a commutator that has become out of round due to excessive heat?
• Which observation during testing best signals a phase-to-phase short in a three-phase stator?
• What does a compounding adjustment involve to regulate voltage under varying loads?
• Which measurement confirms that the generator is producing the correct frequency for grid synchronization?
• LOTO in generator safety stands for what?
• If conductive particles short the areas around the commutator risers, what maintenance action is typically required?
• After starting a generator, what is a key operating check before applying load?
• Some older DC units still operate with which type of bearing?
• Which type of bearing is preferred on rotating machines because of their very low coefficient of friction and maintenance?
• Arc flash can reach temperatures exceeding which approximate value in degrees Fahrenheit?
• What is a common cause of overvoltage in a generator?
• Dust and dirt cause bearing wear primarily through which mechanism?
• What is an essential safety practice before performing generator maintenance?
• Before paralleling a generator to a bus, what three conditions must be matched?
• Compounding in generator control refers to adjusting the interaction between which parts?
• Which material property describes carbon brushes?
• One burnt segment is caused by which interpole strength condition?
• Bearing wear is indicated by which symptom?
• What are the two standard tests used to determine a synchronous generator’s impedance characteristics?
• Which diagnostic method helps identify bearing faults by analyzing frequency content?
• Ball bearings may be open, shielded, or sealed.
• What term describes the period of adjustment required before brushes operate at their best?
• Why should shaft alignment be verified at operating temperature and load?
• Why is documenting maintenance activities and test results important?
• When brush pressure is too what, mechanical wear is the result and higher brush temperatures can promote wear?
• Insufficient brush spring pressure causes what at the carbon-to-copper junction?
• What is the primary objective of a preventive maintenance program for generators?
• The __________ must identify the hazards, determine the safest work practices, and provide the PPE that workers must use to protect themselves from potential flash hazards.
• If the commutator is not mechanically true, what issue is most likely?
• Which protection is most directly associated with detecting and interrupting backward power flow from the grid into the generator, indicating islanding?
• What is the primary protective purpose of PPE in maintenance work?
• What describes isochronous governor control in parallel operation?
• Which component's rattling serves as a telltale sign that the sleeve bearing needs oil?
• Testing and verification of de-energization is performed to ensure there is no dangerous energy remaining before beginning work.
• What is the primary cause of bearing wear and failure?
• Compared to ball and roller bearings, sleeve bearings have a higher coefficient of friction.
• A significant deviation in winding resistance between phases indicates which issue?
• In lockout/tagout, the hasp is used to ______ multiple personal locks.
• The most common causes of _________ _______ include improper seating, bearing misalignment, poor installation, vibration due to imbalance, and passage of electric current through the bearing.
• Which scenario would most justify increasing the frequency of oil analysis?
• There are three types of mounting angles to consider: ______, _______ , and _________.
• Sleeve bearings require _________ inspection for signs of wear.
• What tool is commonly used to assess insulation condition between windings and ground?
• What does the open-circuit (no-load) test primarily determine?
• What is the role of a maintenance preventive plan for generators?
• Brush spacing method quartering is used to check what?
• In parallel operation, if the phase angle is not matched, what issue can occur?
• Bearing oil is described as having which viscosity?
• The trueness of a commutator is held to about what tolerance?
• What could cause voltage fluctuations after synchronization that stabilize slowly?
• On MG sets and DC hoist motors, the correct gap is approximately ____ to ____ inches.
• Which two tasks are among a service mechanic's most important jobs?
• Which statement describes sleeve bearings relative to ball/roller bearings in terms of friction?
• When performing winding resistance checks, what is a typical trend to expect with healthy windings?