Which scenario best summarizes the interactions among fire danger recall behavior, manual operation mode, and shunt trip safety?

Which scenario best summarizes the interactions among fire danger recall behavior, manual operation mode, and shunt trip safety?

• A. Fire danger on recall floor causes the elevator to move to a predetermined alternate floor; Phase two mode enables manual operation of Phase one mode; neither phase can override the shunt trip function
• B. Fire danger triggers the elevator to recall to the lobby; Phase two mode overrides the shunt trip; Shunt trip is bypassed
• C. Fire danger causes immediate shutdown; Phase two mode disables manual operation; Shunt trip irrelevant
• D. No abnormal behavior occurs; Elevator remains in place

Answer: (A)

When a fire condition is detected, the elevator automatically recalls to a designated safe floor to aid evacuation and allow responders access. If that recall floor becomes unsafe, the control logic redirects to a predetermined alternate safe floor. Firefighters can use Phase II to operate the recalled car, but this manual operation does not override safety devices. The shunt trip remains a protective disconnect that must not be bypassed by recall or Phase II operation, ensuring the elevator cannot be driven when conditions are unsafe. This combination—recall to a safe floor, manual operation available within the recalled state, and an active, non-bypassable shunt trip—best describes the interactions.

When a fire condition is detected, the elevator automatically recalls to a designated safe floor to aid evacuation and allow responders access. If that recall floor becomes unsafe, the control logic redirects to a predetermined alternate safe floor. Firefighters can use Phase II to operate the recalled car, but this manual operation does not override safety devices. The shunt trip remains a protective disconnect that must not be bypassed by recall or Phase II operation, ensuring the elevator cannot be driven when conditions are unsafe. This combination—recall to a safe floor, manual operation available within the recalled state, and an active, non-bypassable shunt trip—best describes the interactions.