Elevators - Traction Drives

LTi DRiVES GmbH particularly concentrates on the elevator market and offers special frequency inverters for this application.

Elevator Frequency Inverter CDD3000,L

CDD3000,L is designed for driving gearless or geared synchronous and induction machines. Its control structure is optimised for elevator applications with a 16 kHz sampling rate. The encoder resolution is 33,000,000 increments per revolution if a sin/cos encoder with 2048 oscillations is used. This combination leads to a very high riding comfort in the cabin. In addition CDD3000,L gives the possibility to compensate position errors of the sin/cos encoder by patented GPOC method just as the cogging of the motor. By this measures the tendency of the drive for oscillations and vibrations is suppressed effectively even in critical elevator plants. The load overtaking of the cabin is done position controlled, and if desired with pre-torque-control via load-cell. By that load overtaking is without any jolt or rollback of the cabin.

Elevator Frequency Inverter CDA3000,L

CDA3000 is a frequency inverter for elevators to drive geared induction motors. It can be used in open loop sensorless mode as well as in closed loop mode with rectangular incremental encoder. Open loop mode owns a special slip compensation so that zero position at the floor is reached typically with an accuracy of +2mm.

Common features of elevator inverters CDD3000,L and CDA3000,L

• Power range: 750 W to 90 kW (higher power on demand)
• Overload: 750 W to 15 kW 180% for 30 s and at 22 kW to 90 kW 150% for 60 s
• Switching frequency:
  750 W to 15 kW = 8,12,16 kHz and
  at 22 kW to 90 kW = 4, 8 kHz
• Easy commissioning via motor identification at standstill and motor data bank
• Intuitive operation by control panel or PC-program LiftManager with elevator-specific windows and digital scope
• Arch travel
• Direct landing without creeping velocity
• Integrated sequence control for actuating motor contactor and brake