A fractional-horsepower motor (FHP) is an

electric motor An electric motor is an electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a wire winding to generate for ...

with a rated output power of less than (the term 'fractional' indicates less than one unit). There is no defined minimum output, however, it is generally accepted that a motor with a frame size of less than 35mm square can be referred to as a 'micro-motor'. Fractional-horsepower electric motors are exempt from the US Energy Policy Act of 2005 and the new EN 60034-30:2009 ruling of European directive 2005/32/EC concerning the efficiency classes of low-voltage three-phase

asynchronous motor An induction motor or asynchronous motor is an AC electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding. An induction motor c ...

History

The earliest commercially successful electric motors date back to the latter part of the 19th century when

Nikola Tesla Nikola Tesla ( ; ,"Tesla"
''

induction motor in 1888. The development of fractional-

horsepower Horsepower (hp) is a unit of measurement of power, or the rate at which work is done, usually in reference to the output of engines or motors. There are many different standards and types of horsepower. Two common definitions used today are t ...

motors, however, would not have taken place without the push toward urban, and later, rural electrification, using alternating current. Electrification began in cities around 1900, and Chester Beach, an employee of Hamilton-Beach company, invented a high-speed fractional motor in 1905, which the company used in its

milkshake machine A milkshake machine or drink mixer is a kind of countertop electric mixer used to make milkshakes, flavored milk, frappés, and other blended beverages. Milkshake machines are generally used in ice cream stores and fast food restaurants, and ar ...

, the Cyclone Drink Mixer, introduced in 1910, and sold to urban drugstores for use in their

soda fountains A soda fountain is a device that dispenses carbonated soft drinks, called fountain drinks. They can be found in restaurants, concession stands and other locations such as convenience stores. The device combines flavored syrup or syrup concentrat ...

. Within a few years it was found in most drugstores.Anne Cooper Funderburg, "Milkshake", in Darra Goldstein, ed., ''The Oxford Companion to Sugar and Sweets'', 2015, , ''s.v.'' With electrification, so too came the potential market for washing machines, refrigerators, vacuum cleaners and a host of other commercial appliances. This was recognised by major manufacturers, like Westinghouse and General Electric, who were already in the business of manufacturing large motors for industrial installations. By 1920, over 500,000 fractional-horsepower motors were powering washers and other appliances in America. Following World War II, FHP motor manufacturing experienced a new surge as the demand for consumer goods increased. Since that time, demand for these environmentally-friendly motors has continued to grow and the number of applications that they can be used for continues to rise. For example, most automotive systems, power tools, small machines and appliances use FHP motors. Because of the practicality of FHP motors, they continue to be incredibly popular. In 2017, experts estimated that the European FHP market was worth around US$4.5 billion.George A Schock, Early History of Baldor Electric Co, 1920-1976. Fort Smith, Arkansas: Baldor Electric Co, 1992 After the Second World War, the demand for FHP motors grew, particularly throughout the consumerist boom of the 1950s and 60's. In 2000, the European FHP market was worth an estimated $4.5 billion with some 300-million units in manufacture.Frost and Sullivan, European Fractional Horse Power Motors Market, 17 March 2000

Precision motors

Servo motors A servomotor (or servo motor) is a rotary actuator or linear actuator that allows for precise control of angular or linear position, velocity and acceleration. It consists of a suitable motor coupled to a sensor for position feedback. It also ...

and

stepper motors A stepper is a device used in the manufacture of integrated circuits (ICs) that is similar in operation to a slide projector or a photographic enlarger. ''Stepper'' is short for step-and-repeat camera. Steppers are an essential part of the comp ...

are specialist types of fractional-

s usually intended for high-precision or robotics applications. Usually running from a DC supply, when combined with a

planetary gear An epicyclic gear train (also known as a planetary gearset) consists of two gears mounted so that the center of one gear revolves around the center of the other. A carrier connects the centers of the two gears and rotates the planet and sun gea ...

box can offer accuracies less than 8 arc-minutes (²/₁₅^ths of a degree, or approx. 2.3

milliradian A milliradian ( SI-symbol mrad, sometimes also abbreviated mil) is an SI derived unit for angular measurement which is defined as a thousandth of a radian (0.001 radian). Milliradians are used in adjustment of firearm sights by adjusting t ...

s). Due to their specialized nature, however, these types of motors tend to be expensive compared with standard, or general-purpose lower-precision units.

Applications

Fractional-horsepower motors are used across a wide range of industries and applications for a variety of motion and compression needs. The largest portion of sales can be attributed to the automotive sector, however, accounting for some 35% of all FHP motor sales, driving auxiliary applications such as electric windows, wind-shield wipers, powered seats, wing mirrors, central locking systems, roof openers, and trunk openers. In Europe, the majority of these applications are fulfilled by the industry's largest players: Brose (formerly Siemens), Bosch, and Nidec (formerly Valeo). The second-largest area of consumption is the field of

white goods A major appliance, also known as a large domestic appliance or large electric appliance or simply a large appliance, large domestic, or large electric, is a non-portable or semi-portable machine used for routine housekeeping tasks such as cookin ...

, and small domestic appliances (approximately 12% of the European market). For example, FHP motors are being used to drive pumps and compressors in refrigerators, coffee machines, and washing machines, and they provide suction in vacuum cleaners and a variety of other switching and motion tasks across the ever-increasing variety of domestic products. Until the recent divestment of its motors interests,

Electrolux Electrolux AB () is a Swedish multinational home appliance manufacturer, headquartered in Stockholm. It is consistently ranked the world's second largest appliance maker by units sold, after Whirlpool. Electrolux products sell under a variety ...

was believed to be Europe's largest manufacturer of FHP motors for domestic-appliance applications. Industrial applications consume a similar number of units to that of domestic products with FHP motors being used across a variety of conveyance and process applications. Other applications include: pumps & compressors, medical devices, portable tools, office machinery, and HVAC.

References

External links

CEMEP: Comité Européen de Constructeurs de Machines Electriques et d'Electronique de Puissance

European Union electrical equipment directives

NEMA: National Electrical Manufacturers Association (USA)

IEC: International Electrotechnical Commission

REMA: Rotating Electrical Machines AssociationWhitepaper – Efficiency in Fractional HP Motors & Gearmotors
{{Webarchive, url=https://web.archive.org/web/20140722185447/http://www.groschopp.com/category/literature-media/?a=4205#sthash.V4oggnNs.dpuf: , date=2014-07-22 Electric motors