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CET Elevator practice questions

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Question 1General industry knowledge and safety

Under EN 81-20/50, what is the primary purpose of the ascending car overspeed protection means (ACOP) required on traction elevators?

  1. To keep the car levelled at a floor while passengers load
  2. To hold the doors closed when the car is outside the landing zone
  3. To stop an ascending car in the event of an uncontrolled upward movement Correct answer.
  4. To limit the rated speed of the car during normal travel

Explanation

ACOP is a protective device that arrests the car if it moves upward in an uncontrolled manner, for example after a brake or traction failure. It functions independently of normal speed control and door systems. Its only role is to stop unintended upward motion.

Question 2General industry knowledge and safety

A passenger notices the elevator car floor sits about 25 mm above the landing sill when the doors open. Which condition does this most directly indicate?

  1. Poor levelling accuracy of the car at the landing Correct answer.
  2. A worn door roller on the landing door
  3. Incorrect counterweight guidance
  4. A failed car door interlock

Explanation

Levelling accuracy describes how closely the car floor aligns with the landing sill when stopped. A consistent offset of a few centimetres points to drive or levelling adjustment rather than door hardware. Door and interlock faults would show as door operation problems, not floor height mismatch.

Question 3General industry knowledge and safety

In hydraulic elevator terminology, what does the term 'valve' most commonly refer to in the power unit?

  1. The assembly controlling oil flow to raise, hold and lower the car Correct answer.
  2. The rope termination at the car frame
  3. The landing door locking mechanism
  4. The device that measures car position in the hoistway

Explanation

The valve block in a hydraulic power unit regulates oil flow to the jack, controlling raising, holding and lowering. It is the central hydraulic control element. Position measurement, rope terminations and door locks belong to other subsystems.

Question 4General industry knowledge and safety

What is the function of the governor rope in a traction elevator safety system?

  1. It provides the tension for the landing door closer
  2. It transmits car speed to the overspeed governor so the safety gear can be tripped Correct answer.
  3. It supports the counterweight in the hoistway
  4. It carries the electrical supply to the car lighting

Explanation

The governor rope runs in a loop and drives the overspeed governor sheave, so the governor senses actual car speed. When speed exceeds the trip threshold, the governor grips the rope and activates the safety gear. It is a purely mechanical speed-sensing link.

Question 5General industry knowledge and safety

A technician must enter a pit to inspect buffers. Which practice is required before entering?

  1. Place the car on inspection control, open the pit stop switch and confirm the pit is safe Correct answer.
  2. Leave the car on normal operation so it can be moved if needed
  3. Ask a passenger to hold the landing door open
  4. Disable the alarm bell to avoid noise

Explanation

Pit entry requires the car to be under inspection control and the pit stop switch opened so the car cannot be moved from outside. The technician then verifies the pit is clear and safe. Normal operation, passenger involvement and disabling alarms all increase risk.

Question 6General industry knowledge and safety

What does the term 'rated load' mean for a passenger elevator?

  1. The load at which the safety gear trips
  2. The maximum load the ropes can withstand before breaking
  3. The weight of the empty car and sling
  4. The maximum load the car is designed to carry in normal service Correct answer.

Explanation

Rated load is the design load for normal operation, used for capacity plates and speed/acceleration calculations. It is not the empty car weight nor a failure threshold. Safety devices are set independently of rated load.

Question 7General industry knowledge and safety

Why must the landing door of an elevator be fitted with a locking device that is electrically monitored?

  1. To keep the landing door closed against wind pressure
  2. To prevent the car from moving unless every landing door is closed and locked Correct answer.
  3. To reduce noise from door operation
  4. To allow maintenance staff to open the door from outside

Explanation

The door lock and its electrical contact form part of the safety circuit: the car can only run when all landing doors are closed and locked. This protects against falls into the hoistway. Noise, wind and maintenance access are not the purpose of the monitored lock.

Question 8General industry knowledge and safety

What is the main purpose of the counterweight in a traction elevator?

  1. To guide the car along the rails
  2. To provide emergency braking if the brake fails
  3. To tension the governor rope
  4. To balance most of the car and load weight and reduce motor effort Correct answer.

Explanation

The counterweight offsets the weight of the car plus roughly half the rated load, so the machine only has to overcome the imbalance and friction. This reduces motor size and energy use. It is not a brake, a rope tensioner or a guide.

Question 9General industry knowledge and safety

During a periodic inspection you find the machine room temperature is consistently around 45 °C. Why is this a concern for the elevator?

  1. It has no effect because elevators are rated for any ambient temperature
  2. Excessive heat can degrade lubrication and cause the machine or controller to overheat Correct answer.
  3. It only affects the car interior lighting
  4. It improves traction by warming the sheave

Explanation

Machine room temperature affects oil viscosity, bearing life and controller electronics. Sustained high temperature can accelerate wear and trigger thermal protection. Machine rooms are therefore ventilated to keep within the manufacturer's specified range.

Question 10General industry knowledge and safety

A traction elevator with a 630 kg rated load and 1.6 m/s rated speed is being checked. The governor trip speed is found to be well below the manufacturer's setting. What is the most likely consequence?

  1. The safety gear may trip during normal travel, causing unnecessary emergency stops Correct answer.
  2. The counterweight will become unbalanced
  3. The door locks will fail to engage
  4. The car will run faster than rated speed

Explanation

If the governor trips too early, the safety gear can engage while the car is running at normal speed, producing a sudden stop and possible passenger injury. The trip speed must be set per the manufacturer and standard. It does not change the drive speed, balance or door locking.

Question 11General industry knowledge and safety

Which condition would most likely cause a hydraulic elevator to drift downward slowly while parked at a landing with the doors closed?

  1. A misadjusted landing door roller
  2. A dirty car guide shoe
  3. Internal leakage past the valve or jack seal Correct answer.
  4. A loose governor rope tension weight

Explanation

Slow downward drift in a hydraulic unit usually comes from internal leakage in the valve or the jack seal, allowing oil to escape from the pressurized side. Door rollers, governor tension and guide shoes do not hold the car hydraulically. Such leakage should be investigated promptly.

Question 12General industry knowledge and safety

What is the purpose of the buffer installed at the bottom of the hoistway?

  1. To stop the car at the top landing
  2. To cushion the car or counterweight if it travels below the normal stopping level Correct answer.
  3. To guide the car during travel
  4. To hold the car level during loading

Explanation

Buffers are energy-absorbing devices that limit deceleration if the car or counterweight overtravels downward. They are a last-resort protection, not a normal stopping device. Levelling and guidance are handled by other components.

Question 13General industry knowledge and safety

An elevator has a rated speed of 2.5 m/s. Which statement best describes the role of the car safety gear during a downward overspeed event?

  1. It releases the counterweight to slow the car
  2. It cuts the power supply to the motor only
  3. It grips the guide rails to decelerate and stop the car Correct answer.
  4. It opens the landing doors to allow escape

Explanation

The safety gear is a mechanical device that clamps the guide rails, using friction to decelerate and stop the car. It acts independently of the electrical supply. Cutting power, opening doors or releasing the counterweight would not arrest the car.

Question 14General industry knowledge and safety

What is the primary function of the travelling cable in an elevator installation?

  1. To provide emergency lighting only
  2. To carry power and control signals between the car and the machine room Correct answer.
  3. To tension the governor rope
  4. To suspend the car in the hoistway

Explanation

The travelling cable is a flexible conductor loop that follows the car and carries power and control signals between the car and the controller. It is not a suspension member. Its conductors serve many functions, not only emergency lighting.

Question 15General industry knowledge and safety

A maintenance worker needs to move the car from the pit. Which control arrangement allows safe movement while the worker remains in the pit?

  1. The car top inspection box operated from the landing
  2. Normal car calls from the landing
  3. The emergency alarm button
  4. A portable inspection control station with the pit stop switch in the run position Correct answer.

Explanation

Some installations provide a portable or pit-mounted inspection station so the worker can jog the car while remaining in the pit. The pit stop switch must be in the run position and the worker keeps control at all times. Normal calls, car-top controls and alarms do not serve this purpose safely.

Question 16General industry knowledge and safety

Why are guide rails precisely aligned and securely fixed in an elevator hoistway?

  1. To hold the travelling cable in place
  2. To keep the car and counterweight travelling smoothly and to support safety gear operation Correct answer.
  3. To carry the electrical earthing conductor
  4. To support the landing door frames

Explanation

Guide rails constrain the car and counterweight path, and their alignment is essential for ride quality and for the safety gear to clamp effectively. They are structural components, not electrical conductors or door supports. Poor alignment increases wear and noise.

Question 17General industry knowledge and safety

What does the term 'group control' describe in a multi-car elevator installation?

  1. A single controller shared by cars in separate buildings
  2. A set of cars mechanically linked to one machine
  3. A manual system where a guard sends cars to floors
  4. A dispatcher algorithm that assigns cars to calls to reduce waiting time Correct answer.

Explanation

Group control is the traffic-management logic that allocates landing calls among several cars in the same group, aiming to reduce waiting and travel time. The cars remain independent machines. It is not a mechanical linkage or a manual dispatch system.

Question 18General industry knowledge and safety

A building owner wants to add a new elevator to an existing group of four cars. Which factor most affects whether the new car can join the existing group control?

  1. Compatibility of the new controller with the group dispatch system Correct answer.
  2. The type of floor covering in the lobby
  3. The number of floors served by the building
  4. The colour of the car interior

Explanation

Group dispatch relies on communication and compatible control protocols between cars. A new controller must be able to interoperate with the existing group system. Interior finishes, floor count and lobby materials do not determine group compatibility.

Question 19General industry knowledge and safety

What is the role of the slack rope switch in a traction elevator?

  1. To hold the counterweight in place during maintenance
  2. To measure the tension in the governor rope
  3. To limit the travel of the car at the top floor
  4. To detect a slack or broken suspension rope and stop the machine Correct answer.

Explanation

A slack rope switch monitors suspension rope tension; if a rope goes slack (for example after a failure or the car being supported), it opens the safety circuit and stops the machine. It does not measure governor tension, limit travel or hold the counterweight.

Question 20General industry knowledge and safety

During an inspection, a technician finds the car emergency alarm and intercom are not working. Why is this classified as a significant safety issue?

  1. The counterweight would become unbalanced
  2. The landing doors would not lock
  3. Trapped passengers would have no reliable means to call for help Correct answer.
  4. The car would run faster without the alarm circuit

Explanation

The alarm and intercom are the passenger's means of summoning assistance if trapped. If they fail, entrapment can become prolonged and dangerous. The alarm circuit does not affect speed, door locking or counterweight balance.

Question 21General industry knowledge and safety

Which statement correctly describes the difference between a machine-room-less (MRL) elevator and a conventional traction elevator?

  1. An MRL elevator has no counterweight
  2. An MRL elevator cannot use safety gear
  3. An MRL elevator houses its machine within the hoistway rather than in a separate machine room Correct answer.
  4. An MRL elevator operates only hydraulically

Explanation

MRL designs place the compact machine, often a gearless permanent-magnet unit, in the hoistway, usually at the top, eliminating the separate machine room. They still use counterweights, safety gear and traction drive. They are not limited to hydraulic operation.

Question 22General industry knowledge and safety

A gearless permanent-magnet traction machine is chosen for a high-rise installation. What is the main advantage of this machine type?

  1. It eliminates the need for a counterweight
  2. High efficiency and low maintenance because there is no gearbox Correct answer.
  3. It allows the car to operate without guide rails
  4. It requires no brake

Explanation

Gearless PM machines drive the sheave directly, removing gear losses and gearbox maintenance. They still require a brake, a counterweight and guide rails. The benefit is efficiency, smoothness and reduced wear.

Question 23General industry knowledge and safety

A safety circuit in an elevator controller is best described as which of the following?

  1. A series chain of safety contacts that must all be closed for the car to run Correct answer.
  2. A circuit that controls only the car lighting
  3. A software-only routine with no hardware contacts
  4. A parallel network of call buttons

Explanation

The safety circuit is a series chain of contacts from devices such as door locks, switches and stop buttons. If any contact opens, the chain breaks and the car cannot run. It is a hardware-based protective arrangement, not a call circuit or lighting control.

Question 24General industry knowledge and safety

Why does an elevator with a rated speed above 1 m/s typically use roller guide shoes rather than sliding guide shoes?

  1. Rollers reduce friction and vibration, giving smoother ride quality at higher speeds Correct answer.
  2. Rollers eliminate the need for lubrication entirely
  3. Rollers are cheaper to manufacture than sliding shoes
  4. Sliding shoes cannot be fitted to guide rails

Explanation

At higher speeds, sliding shoes generate more friction, heat and vibration. Roller guides reduce friction and provide smoother, quieter travel. Cost and rail compatibility are not the deciding factors, and rollers may still require some maintenance.

Question 25General industry knowledge and safety

An engineer is evaluating whether a building's elevator can be upgraded to a higher rated speed. Which combination of factors is most critical to review?

  1. Machine capacity, rope and sheave design, safety gear and governor settings Correct answer.
  2. Only the car interior finish
  3. Only the number of stops
  4. Only the door operator brand

Explanation

Increasing rated speed affects the machine, ropes, sheaves, safety gear and governor, all of which must be rated for the new speed. Interior finish, stop count and door brand are not the limiting factors. A full engineering review is required before any speed change.

Question 26General industry knowledge and safety

In elevator terminology, what does the term 'rated load' refer to?

  1. The maximum load that the buffer can absorb during an emergency stop
  2. The maximum number of passengers allowed by the building code
  3. The load the elevator is designed to carry safely under normal operating conditions Correct answer.
  4. The weight of the empty car plus its sling and doors

Explanation

Rated load is the load used by the manufacturer as the basis for the design and testing of the elevator. It is declared on the capacity plate and determines the required traction, braking, and structural strength. It is not simply a passenger count, which depends on average passenger mass, nor is it the empty car weight.

Question 27General industry knowledge and safety

During a periodic inspection you find the machine room temperature is consistently around 45 °C. Why is this a concern for the elevator installation?

  1. The governor will trip at a lower speed because the rope expands
  2. Excessive heat can cause the traction machine to overheat and the controller to malfunction or trip Correct answer.
  3. The oil in the hydraulic power unit will become too viscous to operate the valves
  4. The machine room must be kept below 25 °C to prevent condensation on the controller

Explanation

Elevator machine room equipment is designed for a specified ambient temperature range, typically up to about 40 °C. Above that, motor windings and controller components can overheat, leading to thermal trips, reduced insulation life, and unreliable operation. Ventilation or cooling must be provided to keep the room within the manufacturer's limits.

Question 28General industry knowledge and safety

A traction elevator with a 630 kg rated load and 1.6 m/s rated speed is being checked. The governor trip speed is found to be 2.1 m/s. Which statement best evaluates this result?

  1. The trip speed is too low and the governor must be adjusted upward
  2. The trip speed is too high and the governor must be adjusted downward
  3. The trip speed is within the typical acceptable range for this rated speed Correct answer.
  4. The trip speed is acceptable because it is above the rated speed

Explanation

For a rated speed of 1.6 m/s, the governor trip speed is typically required to be at least 115 % of rated speed and not more than the lesser of 1.25 m/s above rated speed or the value giving a car speed of 1 m/s above rated speed at the governor. A trip speed of 2.1 m/s is about 131 % of rated speed, which falls within the usual acceptable band for this speed.

Question 29General industry knowledge and safety

An elevator has a rated speed of 2.5 m/s. Which statement best describes the role of the car safety gear during a downward overspeed?

  1. It applies gradually to stop the car without exceeding a deceleration limit that could injure passengers Correct answer.
  2. It applies instantly to stop the car in the shortest possible distance
  3. It prevents the car from moving until the doors are locked
  4. It limits the speed of the car to the rated speed during normal travel

Explanation

The safety gear is triggered by the governor when the car exceeds the trip speed. It grips the guide rails to stop the car, but the braking force is controlled so that deceleration stays within limits that protect passengers from injury. Instantaneous application would produce excessive deceleration at high speeds.

Question 30General industry knowledge and safety

A maintenance worker needs to move the car from the pit. Which control arrangement allows safe movement while the worker is in the pit?

  1. A pit inspection station with a deadman switch that limits speed and keeps the worker in control Correct answer.
  2. A jumper installed on the safety circuit to bypass the door locks
  3. A car-top inspection station with a deadman switch and reduced speed
  4. Normal car operating panel controls operated by a second person at the landing

Explanation

A pit inspection station provides a dedicated control point with a deadman (hold-to-run) switch and reduced speed so that the worker in the pit can move the car safely while maintaining continuous control. It also typically includes a stop switch and an alarm. Jumping the safety circuit is dangerous and never permitted.

Question 31General industry knowledge and safety

A building owner wants to add a new elevator to an existing group of four cars. Which factor most affects whether the new car can be integrated into the group control system?

  1. The color of the car interior
  2. The manufacturer of the existing car doors
  3. The number of floors served by the building
  4. The compatibility of the new car's controller and communication protocol with the existing group system Correct answer.

Explanation

Group control relies on communication between the individual car controllers and a group dispatcher. If the new car's controller uses a different protocol or is from a different generation, integration may require a gateway or a full group system upgrade. Interior color, door manufacturer, and floor count do not determine compatibility.

Question 32General industry knowledge and safety

During an inspection, a technician finds the car emergency alarm and intercom are not working. Why is this classified as a safety issue rather than a convenience issue?

  1. Because passengers may be delayed in reaching their floor
  2. Because a trapped passenger must be able to summon help promptly from the car Correct answer.
  3. Because the intercom is used for routine communication between maintenance staff
  4. Because the alarm circuit is part of the door lock circuit

Explanation

The emergency alarm and intercom are life-safety devices. If a passenger becomes trapped due to a power failure or malfunction, they must be able to call for assistance. A non-working alarm can leave a passenger stranded without help for an extended period, which is why codes require it to be operational.

Question 33General industry knowledge and safety

In a traction elevator, what is the purpose of the counterweight?

  1. It balances most of the car and load weight so the machine handles only the imbalance and friction. Correct answer.
  2. It keeps the car level at each landing by adding or removing weight automatically.
  3. It stores energy during descent and releases it during ascent to drive the machine.
  4. It limits the maximum speed of the car by dragging on the guide rails during overspeed.

Explanation

The counterweight is sized close to the car weight plus about half the rated load, so the traction machine only has to overcome the imbalance between the two sides plus friction losses. This reduces motor size, power demand and brake duty. It does not level the car, store energy, or act as a speed limiter.

Question 34General industry knowledge and safety

Which device is intended to stop the car or counterweight if it moves at excessive speed or if the suspension ropes slacken on a traction elevator?

  1. The load weighing device
  2. The buffer
  3. The overspeed governor acting with the safety gear Correct answer.
  4. The door operator interlock

Explanation

The overspeed governor monitors car speed and, at the trip speed, grips its rope to trigger the safety gear that clamps the car to the guide rails. On many designs the governor rope also actuates the safety gear if the ropes go slack, as when the car is caught. Buffers only absorb impact energy at the pit, and door interlocks and load weighing serve unrelated functions.

Question 35General industry knowledge and safety

A technician must perform routine cleaning on top of a car stopped at a landing. Which arrangement is required to make this work safe?

  1. Keep the car on normal automatic operation and work only while the doors are closed.
  2. Leave the landing door open so the technician can be seen and heard from the corridor.
  3. Place the car on inspection control with the car-top inspection station, and stop the car at a level where the top-of-car railing and clearance are adequate. Correct answer.
  4. Rely on the counterweight to hold the car in position without setting any control to inspection.

Explanation

Work on the car top must be done with the car under the control of the person on the roof, using the car-top inspection station and stop switch, with sufficient clearance and guarding. Normal automatic operation and open landing doors expose the worker to unexpected car movement. The counterweight does not lock the car in place.

Question 36General industry knowledge and safety

An elevator is installed in a region subject to earthquakes. Which measure best addresses the risk of the counterweight jumping its guides and the ropes being displaced during seismic movement?

  1. Increasing the rated load of the car to improve traction
  2. Removing the counterweight buffers to give more pit clearance
  3. Fitting counterweight guide-rail retainers and rope-retainer guards Correct answer.
  4. Reducing the counterweight mass to lower the moving load

Explanation

Seismic provisions for elevators typically include retainers or guards that keep the counterweight in its guide rails and prevent ropes from deroping or being thrown off the sheaves during shaking. Increasing load or reducing counterweight mass does not control the displacement risk, and removing buffers reduces protection.

Question 37General industry knowledge and safety

What is the function of the final limit switch on an elevator?

  1. It measures the car speed and triggers the safety gear at overspeed.
  2. It detects that the landing door is closed before the car can start.
  3. It prevents the car from travelling beyond the normal terminal stopping positions if normal stopping fails. Correct answer.
  4. It slows the car as it approaches the top or bottom landing in normal service.

Explanation

The final limit switch is a backup device that cuts the drive if the car passes the normal terminal stopping zone, preventing overtravel into the buffers. Normal slowdown at terminals is done by the control system, and door interlocks and the governor have separate roles.

Question 38General industry knowledge and safety

During a periodic inspection, a technician finds that the car emergency lighting does not come on when the normal power supply is interrupted. Why is this a safety concern?

  1. Because emergency lighting is required so that trapped passengers have illumination until they are rescued. Correct answer.
  2. Because the lighting circuit supplies power to the traction machine during a rescue.
  3. Because the light is needed to keep the governor rope lubricated.
  4. Because the emergency light is part of the door interlock circuit.

Explanation

Emergency lighting is provided so that passengers trapped in a stalled car have adequate illumination while awaiting rescue, which reduces panic and injury risk. It is independent of the traction drive, the door interlock circuit, and any lubrication function.

Question 39General industry knowledge and safety

A hydraulic elevator with a rated speed of 0.63 m/s is being reviewed. Which statement best describes the role of the rupture valve (pipe rupture valve) in its hydraulic circuit?

  1. It limits the descent speed by restricting flow if the cylinder or pipe fails and oil escapes rapidly. Correct answer.
  2. It regulates the oil temperature to keep viscosity constant during long runs.
  3. It prevents the car from rising above the top landing under normal operation.
  4. It acts as a check valve to hold the car at a landing while the pump is stopped.

Explanation

A rupture valve or pipe rupture valve is a safety device that closes or throttles the flow if the hydraulic circuit loses pressure suddenly, limiting the car's descent speed in the event of a pipe or cylinder failure. Temperature control, top-landing overtravel protection, and normal holding are handled by other components.

Question 40General industry knowledge and safety

An engineer is reviewing the brake of a traction machine. Which statement correctly describes the fail-safe principle applied to elevator machine brakes?

  1. The brake relies on the motor's own torque to hold the car, with no mechanical friction element.
  2. The brake is applied by a spring and released by an electromagnet, so it sets if power is lost. Correct answer.
  3. The brake is applied by an electromagnet and released by a spring, so it sets only when commanded.
  4. The brake is released manually by the maintenance worker every time the car stops at a landing.

Explanation

Elevator machine brakes are designed to be fail-safe: springs apply the braking force and an electromagnet lifts the shoes when the machine is energised, so a loss of power or a control fault results in the brake setting. The car is not held by motor torque alone, and the brake is not released manually at every landing.

Question 41Elevator systems and components

In a traction elevator, what is the primary function of the counterweight?

  1. To reduce the unbalanced load the traction machine must lift and to lower the required motor power Correct answer.
  2. To provide emergency braking if the traction sheave loses grip
  3. To absorb vibration transmitted from the guide rails
  4. To tension the governor rope during normal operation

Explanation

The counterweight balances most of the car weight plus a portion of rated load, so the machine only handles the differential load. This reduces required motor torque, power, and energy consumption during normal running. It does not brake the car or tension the governor rope.

Question 42Elevator systems and components

Which device is required to stop a car if it overspeeds in the down direction while running, independent of the ropes?

  1. The final limit switch
  2. The buffer in the pit
  3. The overspeed governor tripping the safety gear Correct answer.
  4. The door interlock circuit

Explanation

The overspeed governor detects excessive speed and mechanically trips the safety gear, which grips the guide rails and stops the car. This protection is independent of the suspension ropes. Buffers only cushion a car reaching the pit, and limit switches only cut power.

Question 43Elevator systems and components

What is the purpose of an elevator buffer?

  1. To smooth the acceleration curve at the start of a run
  2. To damp rope oscillation in tall shafts
  3. To limit the deceleration of the car or counterweight if it travels past the lowest landing Correct answer.
  4. To hold the car level at a floor during loading

Explanation

Buffers are mounted in the pit to absorb the kinetic energy of a car or counterweight that overtravels downward. They limit deceleration to levels tolerable for passengers. They do not affect normal ride quality or levelling.

Question 44Elevator systems and components

A passenger notices the elevator doors will not close when someone stands in the doorway. Which component is most directly responsible for detecting the obstruction?

  1. The door operator motor
  2. The light curtain or door detector Correct answer.
  3. The car door interlock switch
  4. The landing door gib

Explanation

A light curtain or infrared/multi-beam detector senses an obstruction in the door opening and signals the controller to reopen or hold the doors. The motor drives the doors but does not itself sense the obstruction. The interlock proves closure, and the gib guides the panel.

Question 45Elevator systems and components

Which rope construction is most common for elevator suspension in traction installations?

  1. Single-strand solid rod
  2. Synthetic aramid rope only
  3. 8x19 or 6x19 with an independent wire rope core Correct answer.
  4. 6x19 fibre-core wire rope

Explanation

Elevator suspension ropes typically use 6x19 or 8x19 constructions with an independent wire rope core (IWRC) to provide strength and resist crushing on the sheave. Fibre cores are used in some applications but are less common for main suspension. Synthetic ropes are used in some modern gearless systems but are not the general norm.

Question 46Elevator systems and components

What does the term 'rated load' mean for an elevator?

  1. The maximum load the elevator is designed and certified to carry Correct answer.
  2. The load at which the safety gear trips
  3. The weight of the empty car plus counterweight
  4. The load that triggers the overload alarm

Explanation

Rated load is the design capacity stated on the certificate and data plate, used for traction calculations, buffer sizing, and governor setting. The overload alarm is typically set near or slightly below rated load. It is not the empty car weight.

Question 47Elevator systems and components

Which component converts electrical energy into mechanical rotation of the traction sheave in a gearless machine?

  1. The encoder
  2. The governor
  3. The brake coil
  4. The permanent-magnet synchronous motor Correct answer.

Explanation

In a gearless machine, a low-speed permanent-magnet synchronous motor is directly coupled to the sheave and produces the driving torque. The governor is a safety device, the brake coil releases the brake, and the encoder provides feedback.

Question 48Elevator systems and components

What is the main purpose of compensation chains or ropes in a tall elevator installation?

  1. To connect the car to the governor
  2. To increase the rated load of the elevator
  3. To balance the weight of the suspension ropes as the car moves Correct answer.
  4. To provide a secondary suspension in case of rope failure

Explanation

Compensation ropes or chains hang from the car and counterweight and offset the changing weight of the suspension ropes as the car travels. This keeps the traction load balanced over the full travel. They are not a backup suspension or governor connection.

Question 49Elevator systems and components

A technician observes that the elevator stops with the car floor about 20 mm below the landing level. Which system should be checked first?

  1. The buffer stroke
  2. The overspeed governor
  3. The levelling circuit and floor position sensor Correct answer.
  4. The safety gear clearance

Explanation

Levelling accuracy depends on the position feedback (encoder or floor sensor) and the controller's levelling routine. A consistent offset suggests a sensor or parameter issue. The governor, buffers, and safety gear do not control normal stopping position.

Question 50Elevator systems and components

Which condition must be satisfied before a car can start a run with doors closed?

  1. The buffer must be fully compressed
  2. The counterweight must be resting on its buffer
  3. The governor must be tripped
  4. The car door and all landing doors must be closed and locked Correct answer.

Explanation

The door interlock circuit must confirm that the car door and every landing door are closed and locked before the controller permits motion. This prevents movement with an open door. Buffer compression or governor tripping would be abnormal and would prevent operation.