1970's vintage hydraulic elevator

[mshields]

Do hydraulic elevators, particularly those built 45 years ago, have an inrush associated with them upon energization. i.e. with the cars stationary, on the ground floor with the doors open, would a switch to generator power result in an inrush?

Thanks,

Mike

 

[JFletcher]

dunno if this will help you, but where i used to work had four piston/hydraulic elevators (4/5 stories). Had to change the ballasts out on a few, meaning shutting down all power (including hydraulic unit). They stayed on the first floor, didn't "creep" down to the stops, and, when re-energized, they didn't surge/come on. Earliest had Sept 65 blueprints, the others were built early 70s. Thyssen-Krupp models.

Testing your models in question or calling the mfg would probably give you better information.

 

[GoldDigger]

The most likely sources for any inrush would be if the equipment contained a large transformer or a DC supply like in a VFD with storage/filter capacitors.

 

[Jraef]

So start with this; where do you thing the hydraulic power comes from?

A: A hydraulic pump, which will have an electric motor, which will have starting current. On an elevator, even at rest, the hydraulic pump will have to start and recirculate the hydraulic fluid back to a receiver, waiting to see if someone pushes the button. After it sits idle for a while it will turn off and wait, but after a power failure there is often a presumption that the elevator might be needed immediately, so it always starts the pump just in case. Ergo when transferring to a backup generator, you will have the motor starting current immediately.

 

[mshields]

thank you!

thank you!

big help