Door Operators & Interlocks Flashcards
7 cards from real CET practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Door Operators & Interlocks flashcards as text
Which ASME A17.1 rule addresses the requirement for an astragal (or equivalent protection) on multi-panel hoistway doors?
Answer: To prevent fingers from being caught between the leading edges of closing door panels
An astragal or equivalent guard on multi-panel doors prevents finger entrapment in the gap formed between meeting door panel edges during closing.
A technician notices the hoistway door interlock contact closes BEFORE the door is fully closed. This condition is:
Answer: A code violation because the contact must not close until the door is fully closed
ASME A17.1 requires that the interlock electrical contact cannot close until the door is in the closed and locked position, preventing premature car movement.
What is the standard color coding for door safety edge wiring on a DC motor-driven door operator?
Answer: There is no standard color code — refer to the wiring diagram
Elevator wiring color codes are not universally standardized across manufacturers, so technicians must always reference the specific wiring diagram for the equipment being serviced.
On a variable-frequency drive (VFD) door operator, what is the typical purpose of the high-speed and low-speed velocity profiles?
Answer: High speed opens the door rapidly; low speed creeps the door to the fully open or closed position for smooth deceleration
VFD door operators use a high-speed profile for the main travel stroke and a low-speed creep to cushion deceleration at the fully open and fully closed positions.
What does a 'door open' limit switch do on a typical elevator door operator?
Answer: Signals the controller that the door has reached the fully open position and stops or slows the motor
The door open limit switch signals to the controller or door operator logic that the door has reached its fully open position, triggering motor deceleration or stop.
A single-slide (single-speed) hoistway door is driven open by the car door operator through which device?
Answer: A vane or pick-up roller on the car door that engages a strike on the hoistway door
The car door carries a vane or roller that engages a mating strike or clutch on the hoistway door, mechanically coupling them so the car door operator drives both doors simultaneously.
During inspection, a hoistway door is found to be unlockable by hand from the lobby without a drop key. The FIRST corrective action is:
Answer: Take the elevator out of service and repair or replace the defective interlock
A hoistway door that can be opened from the landing without a key is a life-safety hazard; the elevator must be taken out of service until the interlock is repaired.