16.07-1: 1946 Shop Assembled Electric Motor Test Block

HHCC Accession No. 2006.209HHCC Classification Code: 16.07-1

An improvised, FHP, electric motor test block, locally made using standard home electrification hardware components found in the Canadian home of the 1920s to 40’s. Reflecting the ingenuity of HVACR mechanics of the times, the device when connected in series with a potentially faulty motor, limited the current flow, thus protecting the motor and the operator, locally made, circa 1946

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16.07 Electric Motors - Installation, Test and Repair


Shop assembled

Serial No.:

3 x 4 inch x 7 inches high


1.5 Lbs.




Exhibit, education, and research quality, illustrating the array of simple test and measurement devises, improvised and made at home from commonly available component parts - part of a newly emerging service economy in Canada, characteristic the first half of the 20th century.

Patent Date/Number:

From York County (York Region) Ontario, once a rich agricultural hinterlands, attracting early settlement in the last years of the 18th century. Located on the north slopes of the Oak Ridges Moraine, within 20 miles of Toronto, the County would also attract early ex-urban development, to become a wealthy market place for the emerging household and consumer technologies of the early and mid 20th century.

This artifact was discovered in the 1950’s in the used stock of T. H. Oliver, Refrigeration and Electric Sales and Service, Aurora, Ontario, an early worker in the field of agricultural, industrial and consumer technology.

Type and Design:

450 watt 110 volt standard base screw in heater, used as current limiting device connected in series with an electric motor under test.


Double pole, single branch, standard plug fuse cut-out with cover, Smith and Stone, Model 3OA, 125 volt Screw-in, standard base, open coil heater on porcelain body, marked ‘HP’, made in Canada 30 inch, No 18, type C, twin conductor, twisted cloth covered lamp cord, wiring harness with twin Mueller Electric No. 48C -20, Universal, patented, spring attachment clips with black rubber insulating sleeves

Special Features:

The twin plug fuse receptacle allowed for twin heaters to be installed. If the motor appeared to be functional, a second heater could be screwed in, often allowing sufficient current to bring the motor up to speed under no load condition.

Performance Characteristics:
Control and Regulation:
Targeted Market Segment:
Consumer Acceptance:
Market Price:
Technological Significance:

This simple test device tells many stories of its time: something of the hardware employed in home electrification of the period, the relatively simple, elemental nature of the hardware products found in the home The ingenuity of early workers in the refrigeration field, required to diagnosis and repair the electric motor, devising test equipment and building it themselves in period when such equipment was not otherwise available. The new knowledge and skills to be acquired by early workers in the HVACR industry, of electric circuits and systems.

Industrial Significance:
Socio-economic Significance:

It was the 1930’s and as Canada slowly emerged from the economic depression of the period, so too would a new economic sector emerge, the service sector, one which would grow to dominate, contributing much of the country’s economic strength well before the end of the century. The home service trades grew rapidly during this pre W.W.II period and on into the 1950’s, plumber, electrician, heating and refrigeration. They brought with them a new quite different breed of industrial worker, mobile, entrepreneurial, and skilled in the new consumer technologies then available for the Canadian home.

Socio-cultural Significance:

G. Leslie Oliver, The T. H. Oliver HVACR Collection

HHCC Storage Location:
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