Toroidal Variable Transformers, 10-300 kVA
Multi-purpose power source
TOVT’s offer continuously adjustable output voltage for inputs ranging from 120 to 600 Volts AC and provide output voltage as a percent of input voltage over a range of either 0 to 100% or 0 to 117%.
TOVTs are a simple and efficient auto-transformer distinguished by their unique shape. Copper windings encompass a toroidal, or“doughnut” shaped core, to form a toroidal helix. The outer face of the windings is exposed to provide a path for current collection. A carbon brush traverses the windings by means of output voltage selector, or “swinger”. The swinger originates at the center of the toroid and rotates a maximum of 318 degrees about the face of the transformer. The result is an output voltage that varies linearly in proportion to the angle of rotation of the swinger. By stacking multiple transformers on a common shaft and wiring them in series and/or parallel, the line voltage may be doubled and the current and kVA rating increased accordingly
For low KVA applications, TOVT assemblies can be operated manually to provide precise voltage control. For automatic control and larger power ratings a motor drive is required. Motorized units contain a chain and sprocket assembly that can be manipulated to modify the swinger speed with respect to motor rpm, thereby increasing or decreasing regulation time. Limit switches are installed at the upper and lower limits of the windings to prevent over-travel of the voltage selector. Furthermore, DC motor drives can be applied in order to obtain a variable rate of rise.
Each TOVT unit is equipped with lifting points for movement by overhead crane. Also available are IP21 enclosures/cabinets, which provide a protective category designation in accordance with IEC 529. IP21 enclosures protect against penetration of solid objects 12 mm in diameter or larger as well as protect against dripping water. The enclosure is constructed of heavy gauge steel coated with a durable polyurethane based paint. The base of the cabinet rests on steel
skids for movement by forklift.
*Criteria required to generate model number
M = Manual drive (available up to and including “-S6” model
numbers only, larger power ratings require a motorized drive)
N = 120 VAC, 1 phase (rise time 60 seconds)
O = 230 VAC, 1 phase (rise time 60 seconds)
P = 230 VAC, 3 phase (rise time 15 seconds @ 60 Hz)
Q = 90 VDC (rise time 15 seconds)