50 practice questions across 5 topics, each with a written explanation of why the correct answer is correct. Start below — the first questions are free and no account is required.
Electrical Fundamentals & Control Systems
In an elevator control circuit, a safety circuit is wired in:
- A. Parallel, so any open device stops the car
- B. Series, so any open device stops the car
- C. Series-parallel for redundancy
- D. Star topology to the controller
Answer: B. Elevator safety devices (door contacts, buffer switches, governor switch, pit stop switch, etc.) are wired in series. If any single safety device opens the circuit, the safety chain is broken and the elevator stops. This is a fundamental safety design principle — failure of any one device defaults to safe (stopped) state.
Safety Code (ASME A17.1 / CSA B44)
Under ASME A17.1, what is the maximum car speed at which the governor must trip and set the safeties?
- A. Exactly the rated speed of the elevator
- B. 125% of the rated speed for most traction elevators
- C. 150% of the rated speed
- D. The overspeed governor trips at any speed above rated speed
Answer: B. ASME A17.1 requires the overspeed governor to trip (activate safeties) at no more than 125% of the rated speed for most electric traction elevators with Type B safeties. The exact trip speed varies by safety type and elevator class. The governor mechanically trips a rope that activates the car safety, bringing the car to a controlled stop.
Traction Elevator Systems
In a geared traction elevator, the hoist ropes are driven by:
- A. A hydraulic cylinder pushing the car up
- B. A sheave (pulley) connected to a motor through a worm gear reducer
- C. A chain drive connected directly to the motor
- D. A rack-and-pinion gear attached to the guide rails
Answer: B. Geared traction elevators use a motor connected through a worm gear or helical gear reducer to a drive sheave. The hoist ropes wrap around the sheave and support the car and counterweight. The gear reducer allows a smaller, faster motor to develop sufficient torque. Gearless traction elevators connect the motor directly to the drive sheave, requiring a larger, slower motor but offering quieter, more efficient operation at higher speeds.