Interchangeability Chart (.pdf)
VT Product Quick Selector (.pdf)
Schematics & Wiring Diagrams (.pdf)
Variable Transformer Catalog
Terms & Conditions (.pdf)
Staco Energy Products' full range of variable transformers offer the exceptional versatility and reliability required for so many of today's voltage control applications in both industrial and laboratory environments.
Unlike a standard fixed ratio transformer, a Staco variable transformer is designed to provide variable output voltage that can be adjusted from 0 to 117% of the unit's input voltage.
A basic Staco variable transformer consists of a copper winding on a toroidal core of laminated, grain-oriented, silicon steel. A carbon brush, connected to an output terminal, is rotated over the length of a precision-ground, precious metal-plated, commutator track to tap off voltage at any turn from zero volts to the maximum output voltage of the winding.
Plug and Cord Models
Panel Mount, Single Phase Variable Transformers
Ganged Variable Transformer Assemblies
High Current Models
By ganging variable transformers with a common rotor shaft wiring the outputs in parallel, the output current can be greatly increased. The models listed here are capable of output currents up to 315 amps. Other models are available in a variety of ranges.
To download a PDF version of our brochure, click here. For more information, contact your local sales representative or call us directly.
Three Phase Models
All of Staco Energy Products' variable transformers can be ganged with a common rotor shaft and wired for three phase operation, in either open Delta or Wye configuration. For more information, contact your local sales representative, or call the factory directly.
Accessories and Other Configurations of Standard Models
Transformers of the 1010B through 6011 series are available in either "C" style (featuring protective screening over the coil assembly only) or the "CT" style (which also includes a terminal box cover with knockouts to accept conduit. Example part numbers are "1510C, 2510CT."
For applications requiring remote or automatic voltage control, a driving motor can be added to all models of the 501C through 6011 series. Standard motor speeds are: 5, 15, 30 and 60 seconds of travel, and so are designated by the prefix "M." For example: "30M1510."
MP Microprocessor Controller
Our MP series of Microprocessor
provides for easy interface of computer and process controller to
Staco Energy Products' motor driven variable transformers. It is capable
of several operational modes with selectable control ranges - tunable
for various motor speeds, output voltage ramping, and feed back voltage. Custom
options are available.
The FRC-20 controller is designed to position and regulate any Staco motor driven variable transformer. It can be controlled with a 0-5 VDC or 4-20 Ma set point, a 1k ohm potentiometer, or a fixed resistor network.
It maintains a full range regulation of 0.5%, and a limited range regulation of 0.25%. This unit is field configurable for feed back voltages up to 600 VAC, full range/limited range, and type of control. Each FRC-20 includes a 1 amp motor supply fuse and a set point supply trim potentiometer. It is a compact package, and can be easily mounted on the motor plate or inside an enclosure. Contact your sales representative or the factory for current and other feed back alternates.
FRC-20 Controller Brochure (.pdf)
FRC-20 User's Manual (.pdf)