Elevators Power Supply 4

[kingbambina]

Hi,
There was a brief power shudown that occured while switching from main power supply to backup generator for testing. An elevator in an old building was stuck with people trapped in it. An investigation is ongoing and I would like to know from electrical and technical pov what are the requirements for elevators during power outages?

Thanks

 

[LittleInch]

There is usually a manual set of winders in the motor room to lower the car to the nearest floor where another manual key can open the doors.

These motors are often quite large and hence the standby system can't power them. But each system is different.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[RRaghunath]

Modern Elevators have built-in safe landing system using Capacitors as power storage devices.
This ensures that (in the event of power fail) the car is brought to the nearest landing and opens the door.

R Raghunath

 

[FacEngrPE]

ASME A17 family of Elevators and Escalators Codes
Cover the design, construction, installation, operation, testing, inspection, maintenance, alteration, and repair of elevators, dumbwaiters, escalators, moving walks, and material lifts.

It should be possible to use material found in this family of codes, regardless of the age of your elevator, as the basis of comparison for your investigation.
See this link

https://www.asme.org/resources/a17-...Course Codes_Branded_PhraseMatch&gclsrc=3p.ds

If an elevator is part of the life safety egress plan, it may be required to be powered from the buildings emergence power buss - see NFPA 101 life safety code, NFPA 70 national electric code, the building design package, and so on. These systems get complicated, and ongoing maintenance and testing is necessary to ensure they will be available when needed.

 

[iop95]

Most VFD for lift has in special code for this situation and run at minimum power consumption to nearest floor.
Add a separate UPS (dedicated or building UPS line) or battery bank connected to VFD DC bus with needed control/charging circuit.

 

[LittleInch]

Re reading the OP, it could easily be that the system locked out for safety reasons on loss of supply and simply needed resetting, either manually or remotely. Without details of how the control system worked and what it's back up power supply was, or wasn't probably difficult to say what actually happened.

Stopping between floors could easily have caused an error signal on power up so the lowest risk option is to freeze the supply until someone comes to fix it / reset it.


Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[mparenteau]

If you are in the US..I believe the new building code requires some type of closed circuit camera to monitor the elevator in case of a passenger is stuck inside. Check the IBC.

Mike