Starting Systems Questions and Answers

Answer: A

A growler induces current in the armature and a steel blade vibrates over a shorted coil. Testing to the shaft finds an earth fault rather than a short between turns, which makes the last option a real but different test. Reading the definition literally, rather than recalling a summary, avoids the usual confusion. Checking which component actually carries the load settles most questions of this kind at once. Reading the definition literally, rather than recalling a formula, is the reliable route through questions of this shape.

Answer: B

Any continuity to the shaft means the insulation has broken down and the armature is scrap. The winding is never intentionally connected to the shaft. Distinguishing an earth from a short is fundamental to armature testing. Most errors here come from carrying across a result from a neighbouring case where it does not hold. Tracing the requirement back to the physical constraint that produces it makes the answer follow. The shared properties explain why these belong to one family, and the differences explain why more than one exists.

Answer: C

Brushes are replaced when worn below the limit, chipped, or contaminated with oil, which prevents them conducting. A polished bedded face is exactly what a healthy brush looks like. Spring tension is checked at the same time. Naming what changes and what stays the same is the reliable route through questions of this shape. The shared behaviour explains why these belong together and the differences explain why both exist. Checking the units of each quantity catches a wrong formula before the arithmetic begins.

Answer: D

A coil or clock spring keeps constant pressure as the brush wears, and weak springs cause arcing and low output. Brushes bear inward on a commutator, so centrifugal force would lift them rather than pressing them home. Working the distinction through on a single concrete case fixes it more firmly than any rule of thumb. Naming the cost of a choice alongside its benefit is what turns a fact into a design decision. The order in which the effects act is what decides the outcome, so it is worth establishing first.

Answer: A

Reduced pressure means poorer contact, arcing at the interface and less current reaching the armature. Complete loss of contact does occur eventually, which makes the second option the end state of the same fault. A symptom that appears under one condition and not another is what narrows the diagnosis quickly. Most errors here come from carrying across a result from a neighbouring case where it does not hold. Naming the cost of a choice alongside its benefit is what turns a fact into a design decision.

Answer: B

The splines need a trace of grease so the drive slides freely, but oil on the commutator or brushes is fatal. Bushes are lubricated at assembly. Packing the housing would contaminate the commutator immediately. The order in which the effects act is what decides the outcome, so it is worth establishing first. Naming what changes and what stays the same is the reliable route through questions of this shape. Tracing the requirement back to the physical constraint that produces it makes the answer follow.

Answer: C

Sintered bronze bushes impregnated with oil suit the intermittent duty and are cheap to replace. Ball bearings genuinely appear in heavy duty and geared starters, which makes the second option a real construction. Bush wear allows the armature to rub the pole shoes. Checking which component actually carries the load settles most questions of this kind at once. Working the distinction through on a single concrete case fixes it more firmly than any rule of thumb.

Answer: D

Clearance lets the armature drop onto the field poles, which brakes it and draws excessive current. Uneven commutator wear genuinely follows as well, which makes the last option a real consequence of the same wear. Tracing the requirement back to the physical constraint that produces it makes the answer follow. A symptom that appears under one condition and not another is what narrows the diagnosis quickly. Naming the cost of a choice alongside its benefit is what turns a fact into a design decision.

Answer: A

Stop start multiplies the number of starts by a factor of ten or more, so the starter is reinforced or replaced by a belt driven machine. Tandem solenoid starters genuinely permit change of mind restarts, which makes the last option a real technology. The shared behaviour explains why these belong together and the differences explain why both exist. The order in which the effects act is what decides the outcome, so it is worth establishing first. The quantity that varies and the quantity that does not are worth naming before any substitution is attempted.

Answer: B

Two independently controlled solenoids let the pinion be spun to match the coasting ring gear and engage smoothly. That handles a driver who releases the brake during shutdown. Continuous engagement would be destructive. Naming the cost of a choice alongside its benefit is what turns a fact into a design decision. Checking which component actually carries the load settles most questions of this kind at once. Reading the definition literally, rather than recalling a summary, avoids the usual confusion.