Description

The Type 4014 controller relatively simple yet provides great precision in load handling.  It is particularly useful for handling variable loads at preselected subsynchronous speeds, and also provides slower and more stable lowering speeds than other ac stepped wound rotor hoist motion controllers.  Typical applications are in assembly or manufacturing operations where the crane is used frequently.

In this system the eddy current brake and the wound rotor motor are coupled directly to a common shaft.  The brake serves as an artificial load for the motor and develops braking torque by frictionless means; thus, lowering control is stable even at very slow speeds.

The controller acts as a plain reversing controller with five master switch points for hoisting and five for lowering.  In hoisting, the eddy current brake is energized in the first and second point hoist and de-energized in the last three points hoist.  When energized during hoisting, the brake artificially loads the motor thus causing light hook loads to be hoisted slowly.  For lowering, the brake is energized on the first four points lowering and de-energized on the fifth.  When the brake is energized during lowering, its torque opposes the motor torque and permits loads to be lowered slowly.

Type 4014 reversing control panels are suitable for use with ac wound rotor motors on crane hoist drives with eddy current brakes.