Electrically-operated crane control unit 4014

Type 4014 AC Crane Hoist Controller, Electric Load Brake This controller is relatively simple yet providesgreat precision in load handling. It is particularlyuseful for handling variable loads at preselectedsubsynchronous speeds, and also providesslower and more stable lowering speeds thanother ac wound rotor hoist motion controllers.Typical applications are in assembly ormanufacturing operations where the crane isused frequently.In this system the eddy current brake and thewound rotor motor are coupled directly to acommon shaft. The brake serves as an artificialload for the motor and develops braking torqueby frictionless means; thus, lowering control isstable even at very slow speeds.The controller acts as a plain reversing controllerwith five master switch points for hoisting andfive for lowering. In hoisting, the eddy currentbrake is energized in the first and second pointhoist and de-energized in the last three pointshoist. When energized during hoisting, the breakartificially loads the motor thus causing lighthook loads to be hoisted slowly. For lowering,the brake is energized on the first four pointslowering and de-energized on the fifth. Whenthe brake is energized during lowering, its torqueopposes the motor torque and permits loads tobe lowered slowly.Type 4014 reversing control panels are suitablefor use with ac wound rotor motors on cranehoist drives.