Electro-Craft Motomatic E550M Motor Speed Controller 0-5000 RPM 117VAC

Electro-Craft Motomatic E550M Motor Speed Controller 0-5000 RPM 117VAC

The Electro-Craft Motomatic E550M is a benchtop DC motor speed controller designed to precisely regulate motor speed and torque from 0 to 5000 RPM (0 to 12 oz-in) via a front-panel analog meter and adjustable controls. Built by Electro-Craft Corp. of Hopkins, Minnesota, the Motomatic line was engineered for small DC servo and permanent-magnet motor applications requiring accurate closed-loop or open-loop speed control in lab, industrial, and light production settings.

Specifications & What's Included

• Model: E550M (also labeled E-550-M)
• Series: Motomatic — by Electro-Craft Corp., Hopkins, Minnesota
• Input Voltage: 117V AC
• Input Frequency: 50/60 Hz
• Max Input Power: 72.5 VA
• Speed Range: 0 – 5000 RPM
• Torque Range: 0 – 12 oz-in
• Dual-scale analog panel meter: displays both RPM and oz-in simultaneously
• Front-panel controls: Scale Selector (RPM / oz-in), Speed Adjust knob, Direction switch (CCW / Stop / CW), Power ON/OFF toggle, red Power indicator lamp
• Rear-panel controls: Meter Cal, Normal/Command selector, Do Not Overfuse warning, Reset button, Remote input connector
• Rear-panel fuse ratings: 3/4A @ 115V; 3/8A @ 230V
• Rear connectors: Remote input (circular), J2–J4 terminal connectors for motor/signal wiring
• Power transistor output stage with heat sink on rear panel
• Form Factor: Benchtop portable unit with carry handle
• Country of Manufacture: USA
• Includes: Unit with attached AC power cord

Applications

The Electro-Craft Motomatic series was designed for precise speed and torque control of small DC permanent-magnet motors in research, laboratory, and light industrial environments. These controllers are typically used with Electro-Craft's own Motomatic motor line, providing variable-speed drive capability for applications such as precision feed mechanisms, laboratory instrumentation drives, tape transport systems, and small-scale automation. The dual-scale RPM/torque meter allows direct readout without separate instrumentation, making the Motomatic a self-contained benchtop control solution. The remote input on the rear panel allows external command signals to be fed in for automated or integrated setups. Electro-Craft Corp., founded in Hopkins, Minnesota, was a prominent maker of fractional-horsepower DC servo motors and drives from the 1950s through the 1990s; the Motomatic line dates from the mid-to-late 20th century and remains sought after for vintage lab automation, legacy equipment repair, and motor test benches where small, precise DC speed control is needed.