Electric Motors – Single Phase, Shaded Pole
A mid 20th century, 60 cycle, shaded pole, induction motor, suspended on three point rubber vibration isolating mount, from two legged pedestal, with 10 inch 4 blade fan, engineered for condenser fan coil applications on hermetic refrigeration units. Used throughout the 1960’s and beyond, it helped to make possible a new generation of quieter more efficient commercial refrigeration equipment and appliances, Delco Circa 1964.
Technical Significance:
– Representative of a new generation of sleek, compact, more electrically efficient, and customized shaded pole motor technology, for the mid 1960’s.
– With a totally sealed body and bearings, it was a marker of the now rapidly emerging body of engineering and manufacturing practice, moving to a “parts replacement” culture, from the traditional “parts repair” mode of operation.
– The small shaded pole condenser fan motor was a key development in the evolution of the hermetically sealed, commercial refrigeration condensing unit. The refrigeration compressor and drive motor had all of a sudden disappeared, what emerged in its place was a new configuration, with no drive belts, pulleys or drive motor to be seen. The new “hermetically sealed” configuration would be more efficient, quieter, reliable and maintainable. The drive motor was now “unobtrusive” [the motor had disappeared], and “inherent” [part of the compressor], as well as having become “embedded” [in a single envelope} in matters of engineering concept and design. But this new, innovative design concept left behind no compressor motor drive hub on which to mount a fan blade for condenser cooling. Shaded pole motor technology would arrive
– “just-in-time” to take its place and enable a new future for commercial refrigerated appliances and equipment.
– By the 1960’s the success of shaded pole motor technology would help move the Canadian commercial refrigeration industry solidly into a new generation of more compact and efficient forced air cooling units, making possible a wide range of new refrigeration appliances and fresh and frozen food merchandizers.
– The single phase alternating current induction motor has a public face of great simplicity – no commutator, brushes, governor nor switching mechanism to get it started, simply a field winding and solid state [squirrel cage] rotor mounted between two bearings. Its “shading pole(s)” consisting of single turn of wire strategically placed around its pole face(s), is all that is required to start rotation. Yet the shaded pole induction motor is a marvel of early 20th century electrical design engineering. [See Reference No. Chapter XIII, P. 297]
Industrial Significance:
– Its low cost and unique speed-torque characteristics made the shaded pole induction motor ideal for small fan applications of 1/20th HP or less. A “one-of-a-kind”, “just-in-time” technology, it quickly found a special place in 20th century appliances and electrical equipment, where air circulation and ventilation where imperatives.
– A highly innovative shaded pole motor application by Delco, this configuration would become a classic of the commercial refrigeration industry, found on many refrigeration manufacture’s condensing units, here marked specifically for Universal Cooler Co.