Industrial Drive Service (IDS) has been awarded a contract to supply a drive package for the new service hoist at Kirkland Lake Gold, located at Kirkland Lake, Ontario, Canada. The hoist is 12ft and single drum.

The package includes a 2,000hp, 690V AC motor, a 2,000hp AC drive with active front end, an isolation transformer and a DB grid resistor. The 2,000hp drive features a closed-loop Freon cooling system with roof-mounted condensers, KVAR compensation, active damping and a generator mode.

The closed-loop cooling system eliminates the need for external cooling water or glycol. The LCL filter associated with the active front end traditionally produces leading KVARS at a light load. By means of a look-up table, the drive can be set-up to produce lagging KVARS to offset the leading KVARS produced by the filter. The result is that the power factor remains near unity from no load to full load.

Damping resistors have traditionally been used with the LCL filter. The damping resistors are used to prevent resonant current in the LCL filter. The new technology used with the Kirkland Lake Gold drive incorporates a feature that when enabled will prevent the drive’s carrier frequency from approaching the resonant frequency of the LCL filter. This feature allows the damping resistors to be removed from the filter. The damping resistors are a significant source of power loss.

The service hoist is used for emergency purposes in case of power loss. In normal operation, the drive is fully regenerative. When operating with power supplied by a diesel generator, there is limited capacity for regenerative power. In this situation, the grid resistor is used to burn off the regenerated energy. The KVAR control is also useful when operating from an emergency generator as the filter would otherwise create leading power factor that the generator would not be able to handle.

We have been very successful at incorporating AC drives in hoisting applications. The additional features of the new drive make it particularly suitable for use as an emergency hoist drive operating from power produced by a standby generator.

The equipment is scheduled to be commissioned in October 2010.