Warren Type A Synchronous Electric Clock Motor

The type A was the first clock motor commercially produced by Warren Clock Co. Inside the gear box, the rotor spins at 3600 RPM, and two worm gears reduce the speed to 1 RPM. It was made ca. 1916 - 1920.

The type A motor was first described and illustrated in patent #1,283,431, applied for on Aug. 21, 1916 and granted Oct. 29, 1918. Patent #1,283,435, which was applied for on September 29, 1918 and granted on October 29, 1918 gives more details and drawings of the type A. In this patent, Mr. Warren goes into great detail about the size and material of the rotor and how it affects starting torque.

Drawing of top view of type A synchronous motor — United States Patent 1,283,435

Application filed September 29, 1918

Patented October 29, 1918

Patent drawing showing worm gear — United States Patent 1,283,435

Application filed September 29, 1918

Patented October 29, 1918

Example of a type A motor installed in an auxiliary movement. Motor is serial number 2165

Nameplate of motor serial number 2165 — Nameplate of type A motor, serial number 2165

Back view of type A motor — Back view with nameplate removed. The function of the large hole on bottom left is unknown, perhaps it had a removable plug and was used to apply lubricant to the internal gears

Front view of type A motor showing the output pinoion which revolves at 1 RPM — Front view of type A motor showing the output pinion which revolves at 1 RPM

Front internal view of type A motor showing the reduction gearing — Front view of type A motor with bottom cover removed. The vertical worm gear's arbor extends upward to the top and carries the rotor, which rotates at 3600 RPM. This worm engages with the 75 tooth brass gear which carries the second worm gear. The second worm drives a 48 tooth gear which rotates 1 RPM. The 48 tooth gear is mounted on the arbor which carries the output pinion on the front of the motor.

Bottom internal view of type A motor showing the gearbox construction — Bottom view of type A motor with bottom cover removed. The body of the gearbox is made of die-cast material.

Notice the simplicity of the reduction gearing of the type A motor. The succeeding motor, the type B, contains many more moving parts for the reduction gearing, but their size was reduced, resulting in a compact, easy to manufacture unit.

Warren Type A Electric Clock Motor