Superior Electric Powerstat 136-1033 Variable Autotransformer 3-Phase 208V 20A

Superior Electric Powerstat 136-1033 Variable Autotransformer 3-Phase 208V 20A

The Powerstat 136-1033 is a motor-driven variable autotransformer (variac) built by The Superior Electric Company of Bristol, Connecticut. It accepts three-phase 208V input and delivers continuously adjustable output from 0 to 208V at 20A, with a motorized operator that traverses the full range in 5 seconds. The motor operator enclosure (Type 136-1033-MB) is included, making this a self-contained motorized voltage control assembly.

Specifications & What's Included

• Manufacturer: The Superior Electric Company, Bristol, Connecticut, USA
• Series: Powerstat
• Type: 136-1033
• Spec Number: 7607897-P3
• Input Voltage: 208V
• Phase: Three Phase (3-phase)
• Input Frequency: 54/66 Hz
• Output Voltage: 0–208V (continuously adjustable)
• Output Current: 20A
• Cores: Three toroidal autotransformer cores, one per phase
• Motor Operator Type: 136-1033-MB (included)
• Motor Operator Input: 115V, 0.4A, 60 Hz
• Motor Travel Time: 5 seconds (full range)
• Dimensions: 25" x 10" x 9"
• Form Factor: Open frame, pallet-mounted
• Country of Manufacture: United States
• Includes: Motor operator enclosure (Type 136-1033-MB), wiring harness
• Not included: Rack enclosure or external housing

Applications

Motor-driven variacs like the Powerstat 136-1033 are used wherever three-phase voltage needs to be raised, lowered, or ramped gradually under automatic or remote control — without manual intervention at the variac itself. The motorized operator allows the output voltage to be adjusted by a remote control signal, making these units standard in industrial test stations, burn-in and aging racks, power conditioning setups, and equipment startup sequences where a controlled voltage ramp-up (soft-start) is needed to protect motors, transformers, or other inductive loads. Three-phase motorized variacs are also used in telecom power labs, aerospace and defense test facilities, and manufacturing QC lines that require repeatable, programmable voltage sweeps. Superior Electric's Powerstat line was a widely adopted standard in American industry from the mid-twentieth century onward, and the motorized MB-series operator variants were particularly common in automated test and process control applications.