Product Description:

The MX91-FF-402U is a two-phase stepper motor built by Kollmorgen for the MX Hazardous Duty Stepper Motors series. Designed for classified environments, the unit converts pulsed drive signals into precise angular motion so that valves, actuators, or positioning tables advance in fixed increments. The motor produces 200 discrete steps per revolution, allowing open-loop position control in automation zones where feedback devices are impractical. Its sealed construction and insulation system support reliable service when explosive gas or dust is present.

It supports an axial shaft load of 222 N, a value that indicates the maximum compressive force that can be applied along the motor shaft without causing premature bearing wear. A holding torque of 1.27 N·m keeps the shaft locked in place whenever phase current is energized, which prevents drift at standstill. Each phase can draw up to 4.0 A, so the drive electronics must supply that continuous current to achieve rated dynamic torque. The copper windings exhibit a phase resistance of 0.72 Ω; this determines the voltage required to reach the rated current and influences resistive heating. A step angle of 1.8° corresponds to the 200 full-step resolution and is critical when calculating linear travel or index positions in machines such as pick-and-place heads.

The motor frame weighs 2.7 kg, providing enough mass for thermal stability while remaining manageable during installation onto small gantries or pump skids. Positional accuracy at every commanded step is maintained within ±3%, so cumulative error stays low over multiple indexes. The Class B insulation system withstands up to 340 Vdc between windings and frame, enhancing safety when high-voltage drives are used. A thermal resistance of 2.9 °C/W describes how quickly heat moves from the stator to the ambient air, which is useful for checking temperature rise against the duty cycle.