Product Description:

The 12FG is a flat-profile DC servo motor produced by Kollmorgen within the ServoDisc Pancake DC Motors series. This frameless motor has an ironless armature and is intended for positioning tables, semiconductor tools, and other automation axes that require rapid acceleration with low cogging. Its thin pancake geometry minimizes axial space while still delivering continuous torque for closed-loop speed or position control in compact machinery.

The motor’s external body measures 6.00 in in diameter, yet the motor weighs only 5.85 lb, which simplifies payload calculations for gantry and pick-and-place systems. Maximum reflected inertia is rated at 1356 g-cm², so drive tuning can remain responsive without excessive current demand. Power is transmitted through a precision-ground shaft measuring 0.625 +0.000/-0.001 in in diameter. A 0.03 in × 45° chamfer eases coupling insertion, and the 0.750 in shaft extension clears most encoder hubs. The mounting face has a 5.500 in bolt circle with four holes, and each hole is tapped 0.250-20 UNC-2B to a depth of 0.500 in for direct attachment to bulkheads or adapter plates. A 1.313 in shoulder helps locate the housing concentrically. The square keyway accepts a 0.1875 +0.000/-0.0020 in key for positive torque transfer between the shaft and the connected coupling.

The shaft can accept an axial load of 150 lb, while radial loading is limited to 125 lb when applied 1.00 in from the front face. The overall stack length is 3.750 +0.000/-0.062 in, allowing the motor to fit shallow enclosures without spacer rings. Even clamping across the mounting face helps maintain alignment when the motor is secured to a rigid support. The specified radial load position accounts for the bending moment placed on the shaft and bearings by belt tension, gearing, or an offset coupling. Proper support of the driven assembly helps prevent additional side loading that could reduce bearing life. The keyed output provides positive engagement for applications in which a friction-only coupling may not provide sufficient torque transfer.