A completely new drive concept for cable lifts is based on standard lead-acid batteries. With major advantages: solar energy produced on-site can be used to power the lift. Operational safety and reliability is also ensured, even in the case of power loss. This new solution from Hisstema, the Swedish elevator manufacturing company, relies on L1000 series inverter drives from YASKAWA.
Previously, the sole use of standard and rechargeable batteries for lift drives was as a backup power supply. The new system from Hisstema, on the other hand, also employs standard lead-acid batteries during normal operation. This makes the system much more energy efficient than standard models: The batteries are either charged via the normal power supply or from a photovoltaic system with an output of approximately 2 kWh. In the summer months, the lift’s energy consumption of approximately 1.1 kWh can be covered entirely with solar power and any leftover power fed back into the grid. The batteries are of course also suitable for bridging power outages. Up to 300 trips are possible using battery power alone. Unlike the standard emergency evacuation scenarios, the lift doesn’t just travel to the next safe floor, but rather can remain in operation for the entire duration of the power loss.
Cable lifts with a load of up to 630 kg can be easily equipped and retrofitted with the new drive system. The new development from Sweden also complies with all of the requirements of EN 81, the European Lift Standard. The installation only takes up 2500 mm of vertical space in the shaft head. Additionally, a fire retardant power supply cable is required, since operation is ensured at all times by the battery. Two three-phase 230 V motors with an output of 1.1 kW move the lift at a speed of 0.6 m/s. Tests have shown that 70 trips in 24 hours are easily accomplished. An L1000A inverter drive with an output of 5.5 kW is used to control the motor with closed-loop encoder feedback during normal operation. In the case of power loss, a second YASKAWA inverter drive automatically takes over operation: After the lift stops for a maximum of 20 seconds, a compact J1000 provides 230 V of AC power from the battery. The controller, inverters and the drive communicate via a bus system.
The L1000A inverter is part of the L1000 series of YASKAWA inverters designed specifically for lift applications and replaces the tried and tested L7 inverter. The L1000A enables the operation of both induction and permanent magnet motors with speed sensors in the power range from 1.5 to 110 kW. This makes it easy for the inverter to meet strict requirements for precise stopping and smooth travel. Thanks to the wide variety of control options, the L1000A can be combined with virtually any lift control system. The plain text display with lift terminology and units enables very fast startup.
Hisstema AB, Södertälje, Sweden
Lift Inverter Series L1000
Operation of induction and permanent magnet motors with speed sensors in the power range from 1.5 to 110 kW
Precise stopping and smooth travel
Combinable with virtually any lift control system
Plain text display with lift terminology and units for fast startup