Armature (electrical)

A DC armature of a miniature motor (or generator)
A partially-constructed DC armature, showing the (incomplete) windings
A schematic winding diagram for a DC machine with a commutator, showing a wave winding - shown as if the surface of the armature was flattened out

Winding of an electric machine which carries alternating current.

- Armature (electrical)
A DC armature of a miniature motor (or generator)

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Alternators made in 1909 by Ganz Works in the power generating hall of a Russian hydroelectric station (photograph by Prokudin-Gorsky, 1911).

Alternator

Electrical generator that converts mechanical energy to electrical energy in the form of alternating current.

Electrical generator that converts mechanical energy to electrical energy in the form of alternating current.

Alternators made in 1909 by Ganz Works in the power generating hall of a Russian hydroelectric station (photograph by Prokudin-Gorsky, 1911).
In what is considered the first industrial use of alternating current in 1891, workmen pose with a Westinghouse alternator at the Ames Hydroelectric Generating Plant. This machine was used as a generator producing 3,000-volt, 133-hertz, single-phase AC, and an identical machine 3 miles away was used as an AC motor.
Diagram of a simple alternator with a rotating magnetic core (rotor) and stationary wire (stator) also showing the current induced in the stator by the rotating magnetic field of the rotor.
Alternator mounted on an automobile engine with a serpentine belt pulley (belt not present.)

For reasons of cost and simplicity, most alternators use a rotating magnetic field with a stationary armature.

Rotor (lower left) and stator (upper right) of an electric motor

Stator

Stationary part of a rotary system, found in electric generators, electric motors, sirens, mud motors or biological rotors.

Stationary part of a rotary system, found in electric generators, electric motors, sirens, mud motors or biological rotors.

Rotor (lower left) and stator (upper right) of an electric motor
Stator of a 3-phase AC-motor
Stator of a brushless DC motor from computer cooler fan.
Stator winding of a generator at a hydroelectric power station.
Stator of a 3-phase induction motor

In an electric motor, the stator provides a magnetic field that drives the rotating armature; in a generator, the stator converts the rotating magnetic field to electric current.

A relay

Relay

Electrically operated switch.

Electrically operated switch.

A relay
Electromechanical relay schematic showing a control coil, four pairs of normally open and one pair of normally closed contacts
An automotive-style miniature relay with the dust cover taken off
Telegraph relay contacts and spring
Simple electromechanical relay
Operation without flyback diode, arcing causes degradation of the switch contacts
Operation with flyback diode, arcing in the control circuit is avoided
A small cradle relay often used in electronics. The "cradle" term refers to the shape of the relay's armature
Circuit symbols of relays (C denotes the common terminal in SPDT and DPDT types.)
Latching relay with permanent magnet
A mercury-wetted reed relay
(from top) Single-pole reed switch, four-pole reed switch and single-pole reed relay. Scale in centimeters
Solid-state relays have no moving parts.
25 A and 40 A solid state contactors
A DPDT AC coil relay with "ice cube" packaging
Part of a relay interlocking using UK Q-style miniature plug-in relays
Several 30-contact relays in "Connector" circuits in mid-20th century 1XB switch and 5XB switch telephone exchanges; cover removed on one.

A simple electromagnetic relay consists of a coil of wire wrapped around a soft iron core (a solenoid), an iron yoke which provides a low reluctance path for magnetic flux, a movable iron armature, and one or more sets of contacts (there are two contacts in the relay pictured).

The motor from a 3.5 in floppy disk drive. The coils, arranged radially, are made from copper wire coated with blue insulation. The rotor (upper right) has been removed and turned upside-down. The grey ring inside its cup is a permanent magnet. This particular motor is an outrunner, with the stator inside the rotor.

Brushless DC electric motor

Electronically commutated motor (ECM or EC motor) or synchronous DC motor, is a synchronous motor using a direct current (DC) electric power supply.

Electronically commutated motor (ECM or EC motor) or synchronous DC motor, is a synchronous motor using a direct current (DC) electric power supply.

The motor from a 3.5 in floppy disk drive. The coils, arranged radially, are made from copper wire coated with blue insulation. The rotor (upper right) has been removed and turned upside-down. The grey ring inside its cup is a permanent magnet. This particular motor is an outrunner, with the stator inside the rotor.
DC brushless ducted fan. The two coils on the printed circuit board interact with six round permanent magnets in the fan assembly.
Schematic for delta and wye winding styles. (This image does not illustrate the motor's inductive and generator-like properties)
The four poles on the stator of a two-windings single-phase brushless motor. This is part of a computer cooling fan; the rotor has been removed.
A microprocessor-controlled BLDC motor powering a micro radio-controlled airplane. This external rotor motor weighs 5 g and consumes approximately 11 W.

A typical brushless motor has permanent magnets that rotate around a fixed armature, eliminating problems associated with connecting current to the moving armature.

Commutator in a universal motor from a vacuum cleaner. Parts: (A) commutator, (B) brush, (C) rotor (armature) windings, (D) stator (field) windings, (E) brush guides, (F) electrical connections.

Commutator (electric)

Rotary electrical switch in certain types of electric motors and electrical generators that periodically reverses the current direction between the rotor and the external circuit.

Rotary electrical switch in certain types of electric motors and electrical generators that periodically reverses the current direction between the rotor and the external circuit.

Commutator in a universal motor from a vacuum cleaner. Parts: (A) commutator, (B) brush, (C) rotor (armature) windings, (D) stator (field) windings, (E) brush guides, (F) electrical connections.
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Cross-section of a commutator that can be disassembled for repair.
A tiny 5-segment commutator less than 2 mm in diameter, on a direct-current motor in a toy radio control ZipZaps car.
Various types of copper and carbon brushes.
Compound carbon brush holder, with individual clamps and tension adjustments for each block of carbon.
Different types of brushes have different brush contact angles
Commutator and brush assembly of a traction motor; the copper bars can be seen with lighter insulation strips between the bars. Each dark grey carbon brush has a short flexible copper jumper lead attached. Parts of the motor field winding, in red, can be seen to the right of the commutator.
Commutating plane definitions.
Centered position of the commutating plane if there were no field distortion effects.
Actual position of the commutating plane to compensate for field distortion.
Brush advance for Self-Induction.
Low voltage dynamo from late 1800s for electroplating. The resistance of the commutator contacts causes inefficiency in low voltage, high current machines like this, requiring a huge elaborate commutator. This machine generated 7 volts at 310 amps.

It consists of a cylinder composed of multiple metal contact segments on the rotating armature of the machine.

Silver Beauty Growler

Growler (electrical device)

Electrical device primarily used for testing a motor for shorted coils.

Electrical device primarily used for testing a motor for shorted coils.

Silver Beauty Growler

to determine phasing and polarity in multiwinding armatures

Farnsworth in 1939

Philo Farnsworth

American inventor and television pioneer.

American inventor and television pioneer.

Farnsworth in 1939
Philo Farnsworth in the National Statuary Hall Collection, U.S. Capitol, Washington, D.C.
Plaque at the location of Farnsworth's San Francisco laboratory on Green Street.
Statue of Philo T. Farnsworth at the Letterman Digital Arts Center in San Francisco.
Farnsworth's house in Fort Wayne
Yearbook photo of Farnsworth in 1924

He found a burned-out electric motor among some items discarded by the previous tenants, and rewound the armature; he converted his mother's hand-powered washing machine into an electric-powered one.

Some of the many different colors of shellac

Shellac

Resin secreted by the female lac bug on trees in the forests of India and Thailand.

Resin secreted by the female lac bug on trees in the forests of India and Thailand.

Some of the many different colors of shellac
Shellac in alcohol
Lac tubes created by Kerria lacca
Drawing of the insect Kerria lacca and its shellac tubes, by Harold Maxwell-Lefroy, 1909
A decorative medal made in France in the early 20th century moulded from shellac compound, the same used for phonograph records of the period
Blonde shellac flakes
Dewaxed Bona (L) and Waxy #1 Orange (R) shellac flakes. The latter—orange shellac—is the traditional shellac used for decades to finish wooden wall paneling, kitchen cabinets and tool handles.
Closeup of Waxy #1 Orange (L) and Dewaxed Bona (R) shellac flakes. The former—orange shellac—is the traditional shellac used for decades to finish wooden wall paneling and kitchen cabinets.
"Quick and dirty" example of a pine board coated with 1-5 coats of Dewaxed Dark shellac (a darker version of traditional orange shellac)

In motors and generators it also helps transfer force generated by magnetic attraction and repulsion from the windings to the rotor or armature.

General Motors Model 16-248 V16 diesel engine

Balao-class submarine

Successful design of United States Navy submarine used during World War II, and with 120 boats completed, the largest class of submarines in the United States Navy.

Successful design of United States Navy submarine used during World War II, and with 120 boats completed, the largest class of submarines in the United States Navy.

General Motors Model 16-248 V16 diesel engine
5"/25 caliber gun on USS Bowfin (SS-287)
20 mm Oerlikon twin mount displayed near HMCS Haida
Periscope photo from USS Wahoo of a Japanese merchant ship sinking.
USS Catfish (SS-339) in GUPPY II configuration
USS Caiman (SS-323) after GUPPY IA conversion
USS Sabalo (SS-302) after a Fleet Snorkel conversion
USS Razorback (SS-394) after GUPPY IIA conversion
USS Clamagore (SS-343)
USS Cusk (SS-348) fires a Loon missile
A helicopter touches down on Sealion as a transport submarine

Eighteen late Balao-class submarines received low-speed double armature motors which drove the shafts directly and were much quieter, but this improvement was not universally fitted until the succeeding.

A rectifier diode (silicon controlled rectifier) and associated mounting hardware. The heavy threaded stud attaches the device to a heatsink to dissipate heat.

Rectifier

Electrical device that converts alternating current , which periodically reverses direction, to direct current (DC), which flows in only one direction.

Electrical device that converts alternating current , which periodically reverses direction, to direct current (DC), which flows in only one direction.

A rectifier diode (silicon controlled rectifier) and associated mounting hardware. The heavy threaded stud attaches the device to a heatsink to dissipate heat.
Half-wave rectifier
Full-wave rectifier, with vacuum tube having two anodes.
Graetz bridge rectifier: a full-wave rectifier using four diodes.
Full-wave rectifier using a center tap transformer and 2 diodes.
Controlled three-phase half-wave rectifier circuit using thyristors as the switching elements, ignoring supply inductance
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Controlled three-phase full-wave rectifier circuit using thyristors as the switching elements, with a center-tapped transformer, ignoring supply inductance
Disassembled automobile alternator, showing the six diodes that comprise a full-wave three-phase bridge rectifier.
Controlled three-phase full-wave bridge rectifier circuit (B6C) using thyristors as the switching elements, ignoring supply inductance. The thyristors pulse in order V1–V6.
Twelve pulse bridge rectifier using thyristors as the switching elements. One six-pulse bridge consists of the even-numbered thyristors, the other is the odd-numbered set.
Switchable full bridge/voltage doubler.
Cockcroft Walton voltage multiplier
The AC input (yellow) and DC output (green) of a half-wave rectifier with a smoothing capacitor. Note the ripple in the DC signal.
Full-wave diode-bridge rectifier with parallel RC shunt filter
Output voltage of a full-wave rectifier with controlled thyristors
A vibrator battery charger from 1922. It produced 6 A DC at 6 V to charge automobile batteries.
A small motor-generator set
Tungar bulbs from 1917, 2 ampere (left) and 6 ampere
Vacuum tube diodes
Galena cat's whisker detector
Selenium rectifier
A variety of silicon diodes of different current ratings. At left is a bridge rectifier. On the 3 center diodes, a painted band identifies the cathode terminal
Two of three high-power thyristor valve stacks used for long-distance transmission of power from Manitoba Hydro dams. Compare with mercury-arc system from the same dam-site, above.
Voltage drop across a diode and a MOSFET. The low on-resistance property of a MOSFET reduces ohmic losses compared to the diode rectifier (below 32 A in this case), which exhibits a significant voltage drop even at very low current levels. Paralleling two MOSFETs (pink curve) reduces the losses further, whereas paralleling several diodes won't significantly reduce the forward-voltage drop.

The DC generator produces multiphase alternating currents in its armature windings, which a commutator on the armature shaft converts into a direct current output; or a homopolar generator produces a direct current without the need for a commutator.