Buffalo Power Electronics Center, Inc.
Manufacturer of Original Westinghouse Rectifier Products

Buffalo Power Electronics Center, Inc. (BPEC) has continued the manufacturing and support of the AC Thyristor Static Crane Control that was originally a product of the Westinghouse Electric Corporation.

The Class 22-A501 thyristor control, specifically designed for hoist application, provides a high performance, speed regulated drive incorporating the desirable features of static reversing and stepless speed control.  The control employs thyristors to control the flow of power to AC wound rotor crane drive motors.

Application

The Class 22-A501 thyristor control is suitable for all NEMA and CMAA service classes.  Further, the thyristors are continuously rated in excess of the motor full load current rating and include the necessary capacity for accelerating and decelerating current peaks.  This inherent rating characteristic, in addition to the all-static features, makes this control ideally suited for duty cycle application, as well as normal service applications.  Any special duty cycle application does require a review of other power rated components.

Design Features

• Static Reversing:  Hoist and lower control achieved by means of independent thyristors; no reversing contactors required.
• Speed Regulation:  0.5% Operating Deviation Band and 1% Service Deviation Band for regulating speed (NEMA ICS3-106 defined) permits exacting control independent of hook load.
• Adjustable Slow Speeds:  Independent adjustment of first point speeds permits tailoring the drive to the application and eliminates the need for a load float feature.
• Symmetrical Gating Control:  The use of two thyristors per phase assures positive gating control of each halfway of AC voltage.
• Electric Motoring Braking:  Inherent counter torque and regenerative lowering control eliminates the need for mechanical or eddy current load brakes.
• Phase Sequence Indication:  Visual indication of incorrect AC phasing or phase loss.
• Phase Reversal and Loss Protection:  Phase reversal or loss removes power from the drive.
• High Efficiency:  More torque per ampere of line current than possible with similar primary reactor controls.
• Installation Advantages:  Space and weight reduced by more than 50% of similar reactor controls.  Fewer components and less power wiring reduces installation costs.  All front mounted and front wired devices.
• Dependable Thyristor Protection:  Complete thyristor protection provided with coordinated breaker eliminating need for fast clearing fuses.
• Minimum Maintenance:  Industry proven components and simple time proven circuits ensure reliable service under varied loads and duty cycles.
• Improved Servicing:  Plug-in type printed circuit cards are interchangeable between motions and are the same for all Hp's.

The Class 22-A501 control is available for either 230VAC or 460VAC applications.  Table 1 provides a summary of the various horsepower and voltage combinations available.
 
 

The required equipment is available in two different packages.  The first consists of the main controller drive components, which includes the thyristor power modulator (TPM), and intelligence boards mounted in a regulator assembly cage.  A cable connecting the regulator and TPM is also included.  All are supplied as loose unmounted assemblies.  In purchasing this package, the customer has the option of mounting this equipment in their own cabinet, on a panel that will meet their requirements.  The remainder of the required components can be selected based on the customer's preference and requirement.

The second package provides the TPM and regulator mounted on a steel panel.  Also, included are the contactor, circuit breakers and auxiliary relay.  These are all mounted and wired to customer terminal blocks.  All other material needed will be supplied by the purchaser.

Main contractors, main circuit breakers, logic relays, switches, operators controls, lights, operators stations, gates, alarms, primary resistors, secondary resistors, motors, tachometers or master switches are not included.  These items are to be identified and supplied by the purchaser.

The Class 22-A501 controller is tested on a dedicated test fixture, however, a dynamometer testing of the motor and drive is not included.

BPEC offers the Class 22-A501 drive as hardware only.  The coordination, application or integration of this equipment with specifications for a particular bridge project, is the total responsibility of the purchaser.

Typical Class 22-A501 Power Panel