Electric Motors – Single Phase Capacitor Start and Capacitor Run Motors
A latter mid 20th century, high tech, 60cycle capacitor-start motor, a new lighter weight, compact generation of high starting torque refrigeration motors made possible by a market now standardized on 60cycle power; with electrolytic, chemical capacitor, inherent, heat overload protection, and automatic reset, light weight alloy end bells, vibration isolating, rubber, torsion motor mounts, and adaptable base plate, Wagner, Circa 1955.
Technical Significance:
A truly advanced piece of FHP induction motor technology, built for the then rapidly expanding , post W.W.II, 60 cycle, refrigeration equipment market, equipped with advanced engineering features new for the period, including:
Vibration isolating, rubber, torsion motor mounts; Drive bearing extended, safety oilier; Electrolytic, chemical capacitor technology; high tech inherent, overload, thermal protection with automatic reset; Light weight alloy end bells, taking advantage of new high tech metallurgy
The motor exemplifies the latest in automatic over load protection, an on-going challenge through the early years in the development of unitary, fully automated refrigeration equipment, designed to operate safely un-attended in the home.
This generation of FHP capacitor-start motor technology in many ways would stand as a consummate achievement, a kind of icon of “the art form”, made economically possible by the high market demand for FHP motors in the Post W.W.II period. It was now a North American market, largely standardization, on 60 cycle power.
The motor stands as a marker of the golden age in the post W.W.II expansion of the refrigeration industry in Canada, a period which saw the development of the commercial refrigeration market, based on open system refrigeration technology serving food stores, confectioneries, institutions and the like with fractional horsepower belt driven equipment, demonstrating remarkable versatility and inventiveness. It was the last great period of expansion prior to the rush to re-equip the market with a new generation of hermetic [sealed] motor/compressors. Here the motor and compressor would both disappear from, sight both sealed in a single enclosure. The capacitor-start, refrigeration motor, and the advanced 20th century electrical technology that made it possible, as it appears here, would soon disappear withnthe advance of hermetically sealed refrigeration systems.
Industrial Significance:
With the early 1950’s came the opportunity for FHP electric motor manufactures to move too a new generation of designs and styling, as exemplified here. The FHP motor would be smaller and lighter weight technology, made possible by standardisation on 60 cycle power, the development of new more sophisticated engineering design methodologies, new materials and metallurgy, coupled with the economic incentive for development, fostered by a now larger electrically standardized, consumer market place, as well as by a rapidly expanding post W.W.II economy.
The expanding market opportunities of the early 1950’s would attract a new cohort of suppliers to the field. The number of manufactures, working with this basic technology shown here, would increase dramatically throughout the 1950’s, in addition to Delco and Wagner, among many others were: GE [see item 12.06-4], Tamper [see item 12.06-6], Century [see item 12.06-7] and Leland.
This motor stands as a marker of the rapidly expanding, mid 20th century market for FHP motor technology, serving to attract Canadian manufactures. Wagner, a well established US manufacture, like Delco, would find a Canadian manufacturing partner, here the Sangamo Company, Leaside Ontario
Part of the times was also the emergence of a new look and feel for the FHP motor, sleeker more eye appealing, as demonstrated here – less a piece of mere machinery than a mid 20th century, sophisticated piece of electrical apparatus. The new emphasis on styling and eye appeal, along with functionality and performance would reflect the influence of the industrial designer and a new body of industrial styling practice, a development, new, for the mid 20th century.
The development and commercial production of the capacitor-start single phase FHP motor, starting in the mid 1940’s was a seminal event in the history of the HVACR field. The capacitor-start motor would come to replace the more costly and complex repulsion induction motor, RI [See Group 16.01], with one with fewer moving mechanical parts, quieter, more reliable and maintainable, typically at lower cost. By allowing for electrical switching between starting and running windings, it would facilitate external relay control, rather than internal mechanical mechanisms, as with the RI motor. It would therefore be amenable for use in hermetically sealed refrigeration systems.
Early experimentation, leading to the eventual commercial development of the FHP, capacitor start-motor, began with the work of Steinnmetz [American engineer and inventor 1865 – 1923], 40 years before. But commercial production had to await the development of practical capacitors of sufficient capacity, the chemical, electrolytic capacitor. Early, paper capacitors, large enough to provide the required phase shift for motor starting, where larger than the motor itself, and were subject to short operating life span [see Reference 3]
Conventional industrial practice for refrigeration systems, with compressors operating at conventional speeds, in the 1930’s through 60’s, saw these motors attached by “V” belt drive to the refrigeration compressor with a compressor fly wheel about three times that of the diameter of the motor pulley. [see reference #4]. Maintaining belt alignment and tension was a constant challenge, due to close coupling of motor and compressor for space saving.
The race was on, also, to produce an inherently safer motor, safe for the Canadian householder who was required to attend to routine maintenance tasks such as oiling. It was a period well in advance of sealed bearing technology with lifetime lubrication. Wick-oiled bronze bearings of the time required oiling quarterly. In belt driven refrigeration equipment this brought the householder in contact with a moving, compressor drive belt and whirring condenser fan blade. The design of the extended oilier tube would be a simple but significant safety feature, for householder and service man alike, allowing fingers to keep out of danger’s way.