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#Post#: 4--------------------------------------------------
History and Development of Motor
DIR By: AlfredoBuenviaje
Date: August 8, 2016, 7:57 pm
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1. Cite any invention that leads to the development of motors.
#Post#: 20--------------------------------------------------
Re: History and Development of Motor
DIR By: NorHaynieBongcarawan
Date: August 14, 2016, 12:58 am
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Timtable 1856 - 1873: From the invention of the dynamo to the dc
motor
1856
a double-T armature winding. He is the first one to place a
winding into slots.
In 1856, Siemens produces around 50 such devices for the
Bavarian railways. The first machines are designed to deliver
pulses for telegraphs and are operated by hand. They do not
supply continuous electrical energy.
Siemens double-T armature winding
Poggendorffs Annalen der Physik 101 (1857) Taf. II
1861-
1864
knowledge of electromagnetism in four fundamental equations.
These equations are still valid today and fully describe the
theory of electrical engineering.
1866-
1867
double-T armature.
Finally, a powerful electric generator is available and the
advent of electricity begins.
1871
producing a pulsating direct current.
Zénobe Théophil Gramme (Belgium) solves the problem by the
invention of the anchor ring, which produces a smooth DC
voltage. In subsequent years, Gramme's machines are in strong
competition Siemens' double-T armature machines.
#Post#: 23--------------------------------------------------
Re: History and Development of Motor
DIR By: ArleneAncheta
Date: August 14, 2016, 1:11 am
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The first step motor, a bidirectional variable reluctance type,
was developed for the British Navy in 1933. It was used as a
remote position repeater for a compass and gun pointer direction
indicator. The drive was crude but effective for these slow
constant speed applications. The system was later adopted by the
U.S. Navy during World War II. The step motor was used in a
limited number of primitive digital control systems through the
1950s. The predominance of closed-loop continuous ac induction
servos from 1944 to 1957 was soon overcome by the PM step motor
and the availability of digital measuring devices and control
logic necessary for all-digital systems.
By 1960, the PM step motor (large-angle type) had become the
primary step motor in use. There were no cures for resonance or
shaft velocity vibration other than stop the step motor shaft
and restart the motion. The key attributes were the PM step
motor’s open loop position accuracy of +5% and the
non-cumulation of position error. The brush servo (closed-loop)
system or small instrument ac (two-phase) servomotor system
required careful stabilization of the analog feedback signals
(velocity and position). It was a daunting task to close a servo
loop and properly stabilize the servo motor in 1960. Typical
step motor applications in 1960 included drone control readouts,
railway car sorting indicators, portable weighing station
indicators, and digital differential altimeters.
A few years previously, General Electric had developed an ac
synchronous inductor motor for use in low-speed smooth motion
applications. This motor was designed to operate with a 60-Hz,
115-Vac signal and generate smooth continuous motion equivalent
to the movement of an analog clock’s second hand. In 1961,
Snowden and Madsen of Superior Electric Co. announced a new
rendition of the synchronous inductor motor which would become
famous by another name, the hybrid step motor.
Within two years hybrid step motor sales eclipsed that of ac
synchronous inductor motors. The hybrid step motor drive scheme
in 1961 also used a bifilar winding driving the two-phase
winding halves A1, A2, B1, B2. The power supply current was in a
single direction or in a unipolar excitation scheme.
Unipolar-based drive circuits remained popular throughout the
1960s and 1970s.
In 1970, Siemens introduced the first commercial brushless dc
motor, which had an integral tachometer and shaft position
sensor. The two drive methods for two-phase brushless motors
relate to the step motor’s unipolar (star) and bipolar (bridge)
drive circuits.
The Snowden-Madsen paper also displayed another basic drive
scheme; A, A-, B, B-, which represents the bipolar drive scheme.
Two power supplies are needed to support a bipolar
(bidirectional current) drive scheme. While not popular in the
1960s and 1970s, the bipolar drive is the most popular drive
scheme today. One of the first applications for the hybrid step
motor came from the factory automation market. When this step
motor was mechanically coupled to a five-pitch lead screw, the
combination provided a step-by-step motion of 0.001 in. This
step increment worked very well with tables on machine tools,
laboratory, and business machines. Superior Electric was the
pioneer of the hybrid step motor under the SLOSYN brand name to
be joined by others by the late 1960s.
The third major step motor class that gained popularity in the
1960s was the variable-reluctance (VR) step motor. VR step
motors offered low cost, low rotor inertia, moderate speed and
high running torque at the expense of non-linear torque versus
current, high inductance sensitivity to load changes and high
resonance potential. VR step motors were driven with unipolar
currents in dedicated drives different from the drive techniques
used with PM step motors. The popularity of VR step motors used
in computer peripherals peaked in the mid 1970s and began a
decline in market share by 1980. Many VR step motors drove the
paper feeds in both electronic printers and business machines.
Better drive techniques, higher torque capabilities, smaller
step positions, more effective manufacturing and cost control
let the hybrid step motor gain the higher performance segment of
the step motor market.
The fourth major step motor type attacked the VR step motor’s
market share from the low performance segment of the growing
step motor market. The can stack or claw-tooth step motor uses a
low cost construction consisting of a series of sheet metal
parts punched and formed into cups with teeth (claws) that
surround the bobbin coil assembly. The two stator assemblies
(for two phases) are indexed to obtain alternate N-S-N
excitation.
The drive strategies were the same as the hybrid step motor and
the other (large angle) PM step motor. Unipolar drives with
current flowing in a single direction into a two-phase bifilar
winding were the most popular method of driving these lower cost
two-phase step motors. Popular step angles congregated around
7.5 degrees-perstep to 15.0 degrees-per-step. These can stack
two-phase PM step motors grew in popularity in the 1970s and
moved into higher volume lower cost applications in computer
printers, disk drives, and automotive actuators. The can stack
step motor’s performance was sufficient to capture much of the
lower performance computer peripheral market from the VR step
motor by the end of 1979.
The microprocessor burst into the motion market in the early
1970s. It provided a near perfect control “clock” needed to time
the pulse trains to the step motor. Variable pulse rates, then
reaching speeds of 1,000 to 2,000 pulses per second let the step
motor accelerate and decelerate under close timing control.
Overcoming the step motors’ phase inductance and delayed phase
current build up required special drive circuitry. Series
resistance techniques, first reported in 1970, represented by
L/nR, where n = 2 to 4, lower the step motor’s electrical time
constant which allows fast phase current rise and fast
accelerating torque development. Other drive techniques such as
bi-level and dual voltage techniques were developed to overcome
the delay in current caused by higher winding inductances.
The final problem with driving a step motor in an open-loop (no
sensor feedback) mode is the inherent capability to experience
velocity resonance or vibration which can lead to loss of
synchronism and all motion. A number of techniques and circuits
were developed to stabilize step motor shaft motion, under the
category of damping techniques. These new circuits continued to
gain sophistication in the 1960s and 1970s. By 1975, the
digitally controlled step motor (in most forms) was growing at a
faster rate than the analog servosystem driven by brush motors.
A new motor type was emerging from use primarily in the defense
and rotating media industries, the brushless dc motor or
brushless PMDC motor.
The first dc motor called “brushless” was developed by H.D.
Brailsford in the mid 1950s. This pioneering effort greatly
influenced later work. Once the mechanical brushes were
eliminated, these dc motors could operate for surprisingly long
periods with great reliability. The Brailsford motor used spring
contacts to start or commutate the drive transistors. Once in
motion, the contacts flew out, permitting true brushless
operation. This pioneering effort greatly influenced later
designs. The Brailsford motor was then used in applications
involving remote equipment such as portable pollution monitors.
The U.S. Air Force was very interested in brushless dc motors
because of the major problems with dc motor brushes at high
altitudes of 20,000 ft and above. With the start of space
exploration, brush problems became critical. Brush life in space
was then limited to minutes. High peak torque and linear
torque-speed current operation could only be obtained with a
PMDC motor in 1960. When Goddard Space Center surveyed the
American motor industry in 1962, only one U.S. manufacturer had
a working bread board model of an electronically commutated
brushless dc motor. Sperry-Farragut, located in Raleigh-Durham,
N.C., developed the first of a series of brushless dc motors
that would be used in various U.S. space program applications
throughout the 1960s. These brushless dc motors were commutated
by photoelectric sensing of rotor position and possessed
efficiencies more than twice as high as comparable ac
servomotors. The induction of silicon-controlled rectifiers
(SCRs) in 1957 provided the solid state drives used to power
these brushless dc motors.
Brushless dc motors in space and Industry
Brushless dc motors (and their associated SCR drives) were
capable of 1 to 375 W in space qualified applications by 1965.
The oxygencirculating system in the Apollo and the coolant pump
in the Saturn I-B and Saturn V launch vehicles used brushless dc
motors.
By 1965, both Westinghouse and GE were building brushless PMDC
motors. In 1970, GE was building 200-W brushless traction drive
motors for the Lunar Rover. Hall devices developed in 1967 were
beginning to replace optical commutation as the preferred solid
state switching solution. The Hall device developed a voltage
pulse when moving through a magnetic field that can signal
sequential switching of the stator windings. Philips Electronics
in Holland marketed the miniature silicon chip version of the
Hall IC in 1972.
In 1970 Siemens Electric Co. developed the first commercial
product, a battery-powered tape recorder using a two-phase
brushless dc motor and electronic drive for the then unheard of
price of $25, which included the electronic drive as well. The
same brushless dc motor and drive family was still in production
10 years later. Two drive methods for these motors depended on
the step motor’s unipolar (star) and bipolar (bridge) drive
circuits. The double H bridge method became the most popular
drive scheme in the early 1980s. By 1974 most higher performance
applications were using a three-phase drive scheme. This
three-phase, full-wave scheme, the trapezoidal waveform drive,
is still in use today.
A typical example of the full brushless PM servosystem from 1975
displays a brushless dc tachometer used in conjunction with an
optical position encoder and a commutation encoder to provide
velocity, position, and commutation feedback signals,
respectively. The three separate sensors provided commutation,
velocity, and position information to control the analog
brushless dc servosystem in incremental (start-stop) motion.
The PM brushless motor has a different cross-section than a PM
brush motor or an ac induction motor. The stator winding
configurations in a PM brushless motor and a three-phase ac
induction motor are equivalent. But, in the PM brushless motor,
the permanent magnets are attached to a magnetic rotating hub.
The rare earth PM brushless motor possesses superior
acceleration characteristics compared to all other motor types.
The year 1970 brought power efficiencies of 80%, which was far
higher than any other precision motor technology (under 1 KW) at
the time. Two major classes of inner rotor brushless PM motors
emerged from the early designs. The first class, the surface
magnet type, is often called the conventional brushless PM
motor. The second class, the buried magnet type, would become a
major player in the brushless servo markets in the late 1990s.
The development of the rare earth cobalt magnet family by
Wright-Patterson Research Center in Dayton, Ohio in the 1960s
was a major technological breakthrough for motors with permanent
magnets. The samarium cobalt family of permanent magnets
possessed high flux generating capability along with a high
coercive force. These magnets, when properly used in the PM
brushless motor, allowed peak torque levels to reach 5 times
continuous torque levels. The rare earth PM brushless motor
could develop higher peak torques, run at higher efficiency
levels, and accelerate at faster rates. The major barrier to
fast market growth for the PM brushless dc motor and drive was
the significantly higher cost.
By 1976 the brushless dc motor was being considered for larger
industrial applications using X-Y table drives in machine tools
and transfer machines. Two suppliers stood out from the others.
Electrocraft and Indramat were in intense competition to supply
industrial PM brushless dc servosystems in precision positioning
applications on the factory floor. This new servo application
area of 0.5 to 5-kW performance would ultimately require new
drive schemes and cause the brushless dc motor and drive to be
replaced with a new scheme known as the ac servomotor and drive.
#Post#: 24--------------------------------------------------
Re: History and Development of Motor
DIR By: RazelDespuig
Date: August 15, 2016, 9:56 am
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With the invention of the battery (Allessandro Volta, 1800), the
generation of a magnetic field from electric current (Hans
Christian Oersted, 1820) and the electromagnet (William
Sturgeon, 1825) the foundation for building electric motors was
laid. At that time it was still open whether electric motors
should be rotating or reciprocating machines, i.e. simulate a
plunger rod of a steam engine.
Worldwide, many inventors worked in parallel on this task - it
was a "fashion" problem. New phenomena were discovered almost
daily. Inventions in the field of electrical science and its
applications were in the air.
Often the inventors knew nothing about each other and developed
similar solutions independently. National histories are shaped
accordingly until present day. The following is an attempt to
provide a comprehensive and neutral picture.
The first rotating device driven by electromagnetism was built
by the Englishman Peter Barlow in 1822 (Barlow's Wheel).
After many other more or less successful attempts with
relatively weak rotating and reciprocating apparatus the
German-speaking Prussian Moritz Jacobi created the first real
rotating electric motor in May 1834 that actually developed a
remarkable mechanical output power. His motor set a world record
which was improved only four years later in September 1838 by
Jacobi himself. His second motor was powerful enough to drive a
boat with 14 people across a wide river. It was not until
1839/40 that other developers worldwide managed to build motors
of similar and later also of higher performance.
Already in 1833 the German Heinrich Friedrich Emil Lenz
published an article about the law of reciprocity of the
magneto-electric and electromagnetic phenomena, i.e. the
reversibility of electric generator and motor. In 1838 he
provided a detailed description of his experiments with a
Pixii-generator that he operated as a motor.
In 1835 the two Dutchmen Sibrandus Stratingh and Christopher
Becker built an electric motor that powered a small model car.
This is the first known practical application of an electric
motor. In February 1837 the first patent for an electric motor
was granted to the US-american Thomas Davenport.
However, all the early developments by Jacobi, Stratingh,
Davenport and others eventually did not lead to the electric
motors we know today.
The DC motor was not created from these engines, but rather from
the development of power generators (dynamometers). The
foundations were laid by William Ritchie and Hippolyte Pixii in
1832 with the invention of the commutator and, most importantly,
by Werner Siemens in 1856 with the Double-T-anchor and by his
chief engineer, Friedrich Hefner-Alteneck, in 1872 with the drum
armature. DC motors still have a dominant market position today
in the low power (below 1 kW) and low voltage (below 60 V)
range.
The years 1885 until 1889 saw the invention of the three-phase
electric power system which is the basis for modern electrical
power transmission and advanced electric motors. A single
inventor for the three-phase power system can not be named.
There are several more or less well known names who were all
deeply involved in the inventions (Bradley, Dolivo-Dobrowolsky,
Ferraris, Haselwander, Tesla and Wenström).
Today, the three-phase synchronous motor is used mostly in
highly dynamic applications (for example in robots) and in
electric cars. It was developed first by Friedrich August
Haselwander in 1887.
The highly successful three-phase cage induction motor was built
first by Michael Dolivo-Dobrowolsky in 1889. Today, this is the
most frequently produced machine in the power range of 1 kW and
above.
#Post#: 45--------------------------------------------------
Re: History and Development of Motor
DIR By: Lulubels
Date: August 22, 2016, 12:21 am
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With the invention of the battery (Allessandro Volta, 1800), the
generation of a magnetic field from electric current (Hans
Christian Oersted, 1820) and the electromagnet (William
Sturgeon, 1825) the foundation for building electric motors was
laid. At that time it was still open whether electric motors
should be rotating or reciprocating machines, i.e. simulate a
plunger rod of a steam engine.
#Post#: 55--------------------------------------------------
Re: History and Development of Motor
DIR By: theyseemae
Date: August 22, 2016, 2:07 am
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A typical example of the full brushless PM servosystem from 1975
displays a brushless dc tachometer used in conjunction with an
optical position encoder and a commutation encoder to provide
velocity, position, and commutation feedback signals,
respectively. The three separate sensors provided commutation,
velocity, and position information to control the analog
brushless dc servosystem in incremental (start-stop) motion.
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