• South Eastern Equipment Company

DC Motor Speed Drives

The ever increasing use of automation and semi-automatic machinery in industry has in itself produced many problems, one such problem is being the speed control of DC motors at the most economic cost combined with the utmost reliability. South Eastern Equipment Co offers "Thyrostats" ? thyristor control DC motor speed drives that have been specially designed to meet these requirement. They provide an infinitely variable speed adjustment from zero to full rated speed operating from the normal AC single phase supply of 240 V 50 c/s for DC motors up to 5 HP for higher HP motors we have to tap 3-phase 415 V supply. Special features: Thyrostat DC motor controllers are based on the use of thyristors (SCR) with conduction angle control with totally encapsulated trigger circuits offering full wave rectification on both variable armature and field. These units are designed to have light weight easy maintenance of mains transformer, armature SCR-diode unit, field rectifier and triggering circuits. Terminals are provided on lower portion of the rack for mains input and DC outputs, tacho generator, etc. Specifications: supply ? 230/240 V, 50 c/s single phase or alternatively 400/440 V, 50 c/s 3-phase for higher capacity motors; ambient temperature ? -20 to +450C controllers can operate without losing any efficiency; speed range ? the standard models listed are capable of a speed range of 20:1; protection ? adjustable automatic current limiting circuits are included which ensure the complete protection of the silicon devices and the motor against excessive repetitive peak currents; for short circuit conditions a high rupturing capacity fuses are employed; RC network around each semiconductor is provided; and field failure relay provided with interlocking system with armature circuit.