Mikhail Dolivo-Dobrovolsky

Mikhail Osipovich Dolivo-Dobrovolsky
Dobrovolsky, age 22

Russian Empire-born engineer, electrician, and inventor active in the German Empire and also in Switzerland.

- Mikhail Dolivo-Dobrovolsky
Mikhail Osipovich Dolivo-Dobrovolsky

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AEG

German producer of electrical equipment founded in Berlin as the Deutsche Edison-Gesellschaft für angewandte Elektricität in 1883 by Emil Rathenau.

German producer of electrical equipment founded in Berlin as the Deutsche Edison-Gesellschaft für angewandte Elektricität in 1883 by Emil Rathenau.

Founder Emil Rathenau.
Artificial electrically powered waterfall at the International Electro-Technical Exhibition – 1891.
AEG power station built in 1930. Krivoy Rog city.
AEG turbine factory (1909, architect Peter Behrens)
Memorial plaque for Polish forced labourers at AEG in Blechhammer camp near Auschwitz
Berlin memorial plaque for Polish forced labourers at AEG in Berlin-Gesundbrunnen, Germany.
AEG electric motor builders plate.
AEG electric locomotive.
AEG G.IV bomber (World War I).
Share of the Deutsche Edison-Gesellschaft für angewandte Elektricität, issued 20 may 1883

In 1887 Mikhail Dolivo-Dobrowolsky joined the company as chief engineer, later becoming vice-director.

Three-phase totally-enclosed fan-cooled (TEFC) induction motor with end cover on the left, and without end cover to show cooling fan on the right. In TEFC motors, interior heat losses are dissipated indirectly through enclosure fins, mostly by forced air convection.

Induction motor

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.

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.

Three-phase totally-enclosed fan-cooled (TEFC) induction motor with end cover on the left, and without end cover to show cooling fan on the right. In TEFC motors, interior heat losses are dissipated indirectly through enclosure fins, mostly by forced air convection.
Cutaway view through stator of TEFC induction motor, showing rotor with internal air circulation vanes. Many such motors have a symmetric armature, and the frame may be reversed to place the electrical connection box (not shown) on the opposite side.
A model of Nikola Tesla's first induction motor at the Tesla Museum in Belgrade, Serbia
Squirrel-cage rotor construction, showing only the center three laminations
A three-phase power supply provides a rotating magnetic field in an induction motor
Inherent slip - unequal rotation frequency of stator field and the rotor
Typical torque curve as a function of slip, represented as "g" here
Speed-torque curves for four induction motor types: A) Single-phase, B) Polyphase cage, C) Polyphase cage deep bar, D) Polyphase double cage
Typical speed-torque curve for NEMA Design B Motor
Magnetic flux in shaded pole motor.
Typical speed-torque curves for different motor input frequencies as for example used with variable-frequency drives
Typical winding pattern for a three-phase (U, W, V), four-pole motor. Note the interleaving of the pole windings and the resulting quadrupole field.

Steadfast in his promotion of three-phase development, Mikhail Dolivo-Dobrovolsky invented the cage-rotor induction motor in 1889 and the three-limb transformer in 1890.

Three-phase transformer with four wire output for 208Y/120 volt service: one wire for neutral, others for A, B and C phases

Three-phase electric power

Common type of alternating current used in electricity generation, transmission, and distribution.

Common type of alternating current used in electricity generation, transmission, and distribution.

Three-phase transformer with four wire output for 208Y/120 volt service: one wire for neutral, others for A, B and C phases
The first AC motor developed by Italian physicist Galileo Ferraris. This was a two-phase motor and required four wires.
Normalized waveforms of the instantaneous voltages in a three-phase system in one cycle with time increasing to the right. The phase order is 1‑2‑3. This cycle repeats with the frequency of the power system. Ideally, each phase's voltage, current, and power is offset from the others’ by 120°.
Three-phase electric power transmission lines
Three-phase transformer (Békéscsaba, Hungary): on the left are the primary wires and on the right are the secondary wires
Animation of three-phase current
Wye (Y) and delta (Δ) circuits
A delta-wye configuration across a transformer core (note that a practical transformer would usually have a different number of turns on each side).
A transformer for a "high-leg delta" system used for mixed single-phase and three-phase loads on the same distribution system. Three-phase loads such as motors connect to L1, L2, and L3. Single-phase loads would be connected between L1 or L2 and neutral, or between L1 and L2. The L3 phase is 1.73 times the L1 or L2 voltage to neutral so this leg is not used for single-phase loads.
Three-phase AC generator connected as a wye or star source to a wye or star connected load
Three-phase AC generator connected as a wye source to a delta-connected load
Three-phase electric machine with rotating magnetic fields
Three phase plug used in the past on electric stoves in Germany

Polyphase power systems were independently invented by Galileo Ferraris, Mikhail Dolivo-Dobrovolsky, Jonas Wenström, John Hopkinson, William Stanley Jr., and Nikola Tesla in the late 1880s.

Animation showing operation of a brushed DC electric motor.

Electric motor

Electrical machine that converts electrical energy into mechanical energy.

Electrical machine that converts electrical energy into mechanical energy.

Animation showing operation of a brushed DC electric motor.
Cutaway view through stator of induction motor.
Faraday's electromagnetic experiment, 1821
Jedlik's "electromagnetic self-rotor", 1827 (Museum of Applied Arts, Budapest). The historic motor still works perfectly today.
An electric motor presented to Kelvin by James Joule in 1842, Hunterian Museum, Glasgow
Electric motor rotor (left) and stator (right)
Salient-pole rotor
Commutator in a universal motor from a vacuum cleaner. Parts: (A) commutator, (B) brush
Workings of a brushed electric motor with a two-pole rotor and PM stator. ("N" and "S" designate polarities on the inside faces of the magnets; the outside faces have opposite polarities.)
A: shunt B: series C: compound f = field coil
6/4 pole switched reluctance motor
Modern low-cost universal motor, from a vacuum cleaner. Field windings are dark copper-colored, toward the back, on both sides. The rotor's laminated core is gray metallic, with dark slots for winding the coils. The commutator (partly hidden) has become dark from use; it is toward the front. The large brown molded-plastic piece in the foreground supports the brush guides and brushes (both sides), as well as the front motor bearing.
Large 4,500 hp AC induction motor.
A miniature coreless motor
A stepper motor with a soft iron rotor, with active windings shown. In 'A' the active windings tend to hold the rotor in position. In 'B' a different set of windings are carrying a current, which generates torque and rotation.

Steadfast in his promotion of three-phase development, Mikhail Dolivo-Dobrovolsky invented the three-phase induction motor in 1889, of both types cage-rotor and wound rotor with a starting rheostat, and the three-limb transformer in 1890.

Electrical engineering

Engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electronics, and electromagnetism.

Engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electronics, and electromagnetism.

The discoveries of Michael Faraday formed the foundation of electric motor technology.
Guglielmo Marconi, known for his pioneering work on long-distance radio transmission
A replica of the first working transistor, a point-contact transistor
Metal–oxide–semiconductor field-effect transistor (MOSFET), the basic building block of modern electronics
The top of a power pole
Satellite dishes are a crucial component in the analysis of satellite information.
Control systems play a critical role in spaceflight.
Electronic components
Microprocessor
A Bayer filter on a CCD requires signal processing to get a red, green, and blue value at each pixel.
Flight instruments provide pilots with the tools to control aircraft analytically.
Supercomputers are used in fields as diverse as computational biology and geographic information systems.
The Bird VIP Infant ventilator
Oscilloscope
An example circuit diagram, which is useful in circuit design and troubleshooting.
Belgian electrical engineers inspecting the rotor of a 40,000 kilowatt turbine of the General Electric Company in New York City
The IEEE corporate office is on the 17th floor of 3 Park Avenue in New York City
Satellite communications is typical of what electrical engineers work on.
The Shadow robot hand system
A laser bouncing down an acrylic rod, illustrating the total internal reflection of light in a multi-mode optical fiber.
Radome at the Misawa Air Base Misawa Security Operations Center, Misawa, Japan

Alternating current, with its ability to transmit power more efficiently over long distances via the use of transformers, developed rapidly in the 1880s and 1890s with transformer designs by Károly Zipernowsky, Ottó Bláthy and Miksa Déri (later called ZBD transformers), Lucien Gaulard, John Dixon Gibbs and William Stanley, Jr. Practical AC motor designs including induction motors were independently invented by Galileo Ferraris and Nikola Tesla and further developed into a practical three-phase form by Mikhail Dolivo-Dobrovolsky and Charles Eugene Lancelot Brown.

Squirrel cage rotor

Squirrel-cage rotor

Rotating part of the common squirrel-cage induction motor.

Rotating part of the common squirrel-cage induction motor.

Squirrel cage rotor
Diagram of the squirrel-cage (showing only three laminations)
Laminations, with 36 slots for the stator and 40 slots for the rotor

In 1889, Mikhail Dolivo-Dobrovolsky developed a wound-rotor induction motor, and shortly afterwards a cage-type rotor winding.

Alternating current (green curve). The horizontal axis measures time (it also represents zero voltage/current) ; the vertical, current or voltage.

Alternating current

Electric current which periodically reverses direction and changes its magnitude continuously with time in contrast to direct current (DC) which flows only in one direction.

Electric current which periodically reverses direction and changes its magnitude continuously with time in contrast to direct current (DC) which flows only in one direction.

Alternating current (green curve). The horizontal axis measures time (it also represents zero voltage/current) ; the vertical, current or voltage.
A schematic representation of long distance electric power transmission. From left to right: G=generator, U=step up transformer, V=voltage at beginning of transmission line, Pt=power entering transmission line, I=current in wires, R=total resistance in wires, Pw=power lost in transmission line, Pe=power reaching the end of the transmission line,  D=step down transformer, C=consumers.
Three-phase high-voltage transmission lines use alternating currents to distribute power over long distances between electric generation plants and consumers. The lines in the picture are located in eastern Utah.
A sine wave, over one cycle (360°). The dashed line represents the root mean square (RMS) value at about 0.707.
The Hungarian "ZBD" Team (Károly Zipernowsky, Ottó Bláthy, Miksa Déri), inventors of the first high efficiency, closed-core shunt connection transformer
The prototype of the ZBD transformer on display at the Széchenyi István Memorial Exhibition, Nagycenk in Hungary
Westinghouse Early AC System 1887
(US patent 373035)

This design was further developed into the modern practical three-phase form by Mikhail Dolivo-Dobrovolsky, Charles Eugene Lancelot Brown.

Pole-mounted distribution transformer with center-tapped secondary winding used to provide "split-phase" power for residential and light commercial service, which in North America is typically rated 120/240 V.

Transformer

Passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits.

Passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits.

Pole-mounted distribution transformer with center-tapped secondary winding used to provide "split-phase" power for residential and light commercial service, which in North America is typically rated 120/240 V.
Ideal transformer connected with source VP on primary and load impedance ZL on secondary, where 0 < ZL < ∞.
Ideal transformer and induction law
Leakage flux of a transformer
Real transformer equivalent circuit
Instrument transformer, with polarity dot and X1 markings on low-voltage ("LV") side terminal
Power transformer overexcitation condition caused by decreased frequency; flux (green), iron core's magnetic characteristics (red) and magnetizing current (blue).
Laminated core transformer showing edge of laminations at top of photo
Interleaved E-I transformer laminations showing air gap and flux paths
Laminating the core greatly reduces eddy-current losses
Small toroidal core transformer
Windings are usually arranged concentrically to minimize flux leakage.
Cut view through transformer windings.
Legend: 
White: Air, liquid or other insulating medium 
Green spiral: Grain oriented silicon steel 
Black: Primary winding 
Red: Secondary winding
Cutaway view of liquid-immersed transformer. The conservator (reservoir) at top provides liquid-to-atmosphere isolation as coolant level and temperature changes. The walls and fins provide required heat dissipation.
Substation transformer undergoing testing.
An electrical substation in Melbourne, Australia
showing three of five 220 kV – 66 kV transformers, each with a capacity of 150 MVA
Camouflaged transformer in Langley City
Transformer at the Limestone Generating Station in Manitoba, Canada
Schematic of a large oil-filled power transformer 1. Tank 2. Lid
3. Conservator tank 4. Oil level indicator 5. Buchholz relay for detecting gas bubbles after an internal fault 6. Piping
7. Tap changer 8. Drive motor for tap changer 9. Drive shaft for tap changer
10. High voltage (HV) bushing
11. High voltage bushing current transformers
12. Low voltage (LV) bushing
13. Low voltage current transformers
14. Bushing voltage-transformer for metering
15. Core 16. Yoke of the core
17. Limbs connect the yokes and hold them up 18. Coils
19. Internal wiring between coils and tapchanger
20. Oil release valve
21. Vacuum valve
Faraday's experiment with induction between coils of wire
Induction coil, 1900, Bremerhaven, Germany
Faraday's ring transformer
Shell form transformer. Sketch used by Uppenborn to describe ZBD engineers' 1885 patents and earliest articles.
Core form, front; shell form, back. Earliest specimens of ZBD-designed high-efficiency constant-potential transformers manufactured at the Ganz factory in 1885.
The ZBD team consisted of Károly Zipernowsky, Ottó Bláthy and Miksa Déri
Stanley's 1886 design for adjustable gap open-core induction coils
"E" shaped plates for transformer cores developed by Westinghouse

In 1889, Russian-born engineer Mikhail Dolivo-Dobrovolsky developed the first three-phase transformer at the Allgemeine Elektricitäts-Gesellschaft ('General Electricity Company') in Germany.

Louis IV, Grand Duke of Hesse-Darmstadt

Technische Universität Darmstadt

Research university in the city of Darmstadt, Germany.

Research university in the city of Darmstadt, Germany.

Louis IV, Grand Duke of Hesse-Darmstadt
Eagle above the rear main entry to the Robert Piloty Building, nowadays home to the Department of Computer Science. Note the effaced swastika under the eagle
Peter Grünberg
Chairman of the Board of Management of BMW AG
Chaim Weizmann
Georg Cantor
Robot Florian at the DARPA Robotics Challenge 2015
Robot Johnny 05 at the DARPA Robotics Challenge 2015
Robot Argonaut at the ARGOS Challenge
Hector UGV identifies a victim using a probabilistic world model, based on information from heterogeneous sensors
Robert Piloty Building, named after Robert Piloty, a German computer scientist and Professor of Electrical Engineering at TU Darmstadt, used by the Department of Computer Science, 2006
Altes Hauptgebäude of Technische Universität Darmstadt, 2008
Kantplatz, Darmstadt, 2007
Darmstadt former Ducal Palace, now part of TU Darmstadt, with market square
Campus Square, Inner City Campus of TU Darmstadt, with University Library and sculpture "Bueste" by Franz Bernhard
Main Entrance and Administrative Building, City Campus TU Darmstadt 2018
Canteen at Campus Lichtwiese, 2007
Giant gear in front of the mechanical engineering building, 2007
Building used by the Department of Architecture, 2007
Institute of Materials Science, TU Darmstadt Lichtwiese Campus
Lecture Halls and Library Building at Lichtwiese Campus
Greenhouse, 2009
Botanical Garden Campus of TU Darmstadt
August Euler Airfield, 2011

Mikhail Dolivo-Dobrovolsky, inventor of the three-phase electrical motor

Oskar von Miller

Oskar von Miller

German engineer and founder of the Deutsches Museum, a large museum of technology and science in Munich.

German engineer and founder of the Deutsches Museum, a large museum of technology and science in Munich.

Oskar von Miller

At this exhibition Mikhail Dolivo-Dobrovolsky succeeded in transmitting 20,000 V three-phase alternating current 176 kilometers from Lauffen am Neckar to Frankfurt am Main, a technical masterpiece and significant breakthrough in the transmission of alternating current.