LIFT UPS is an OFF LINE UPS which has 3 main parts namely – Charger, Inverter and Batteries. As majority of Elevators use three phase power supply, the UPS also is three phase input and three phase output type. It means, the LIFT UPS takes three phase supply and feeds to Elevator simultaneously charging the batteries. In case of a power cut, the inverter turns on battery mode and generates three phase output to feed the load. This transition takes place within a time period of 15-20 seconds depending upon the configuration of the variable frequency drive (VFD / V3F) used by the elevator. (Renutron has recently developed a system such that the near zero transfer from utility to battery mode is possible for any type of VF drive) When the mains supply or utility gets restored, the elevator is transferred automatically to mains supply and battery charging starts. Depending upon the size and number of batteries the backup time can be extended from 2-3 Hours up to 8 Hours too.
While designing the Lift back up power solution various parameters such as normal power cut duration, type of Lift ( with or without VFD ), lift motor capacity, if the building is residential or commercial, number of floors & number of flats, usage of Lift and any other load such as staircase / parking / garden lights, water or fire-fighting pump CCTV or any other similar needs to be backed up are considered.