How much generator capacity is required for a lift?
The generator required for a lift depends on more than the lift motor's kW rating. Generator sizing should also consider the number of lifts, motor power factor, lift auxiliary loads, whether multiple lifts can operate together, other essential building loads and the starting characteristics of the lift drive system.
Volo's Lift Generator Load Calculator provides an indicative DG capacity in kVA for preliminary planning. It is useful when planning a new building, apartment, villa, commercial property, hospital, office or other building with an elevator.
Why is generator capacity specified in kVA?
Generator sets are commonly rated in kVA because the generator alternator has to supply both useful electrical power and reactive current associated with connected loads. Motor power factor therefore affects the apparent power requirement.
Does lift motor kW equal generator kVA?
No. A lift motor's kW rating should not simply be treated as the final generator capacity. The motor's power factor, controller characteristics, auxiliary loads and starting behaviour need to be considered.
What loads should be considered with a lift generator?
- Lift traction motor load
- Lift controller and electrical auxiliaries
- Cabin lighting and ventilation
- Multiple lift operation
- Water pumps where required
- Essential building lighting
- Fire and safety systems
- Security systems
- Other equipment intended to operate on DG supply