Auto Variable Transformers

STERCO product line includes variable transformers, the most versatile and reliable voltage controls available, Variable transformers have many industrial and laboratory applications as basic components to control voltage, current, power, heat, speed, light, and electromechanical force. A basic Variable Transformer consists of a single layer, magnet wire winding on a toroidal core of laminated silicon steel. A carbon brush, connected to an output lead, is rotated over a precision ground, plated commutator track 10 tap off voltage at any turn from zero to the maximum output voltage of the winding.

EFFICIENCY & DISTORTION LESS VOLTAGE CONTROL
In contrast to inefficient, wattage-burning resistive-type controllers such as rheostats, Stereo Variable Transformers have an extremely low power loss and efficiencies as high as 98%. Stereo Variable Transformers deliver any desired voltage (within the transformer rating) with negligible variation in output voltage from no-load to full-load current. It produce an accurate transfer of input wave to output circuit, providing distortion less voltage control (a requisite of many sophisticated electronic applications).
PLATED COMMUTATOR SURFACE
The commutator surface of each coil is specially plated with precious metal, giving Stereo commutators longer life, increased resistance to corrosion and the capacity to withstand greater overloads (while maintaining a constant contact voltage drop).
LONGER LIFE WITH NEGLIGIBLE MAINTENANCE
Precise design assembly of the brush provides excellent mechanical performance, long life, and low-driving torque. Brush replacement is seldom needed and it can be easily replaced, if required. Due to high safety margins of voltage, current-carrying capacity and dielectric strength, longer life of the unit can be expected.
RUGGED MECHANICAL CONSTRUCTION
Sterco Variable Transformers are precision built to exacting mechanical tolerances using the finest materials available. Quality assurance inspections are performed to insure that the high designed in quality is maintained throughout the manufacturing cycle. A Stereo Variable Transformer provides accurate, reliable and lasting voltage control for a broad variety of applications.