Linear alternator

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Essentially a linear motor used as an electrical generator.

- Linear alternator
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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.)

Occasionally, a linear alternator or a rotating armature with a stationary magnetic field is used.

A model of a Stirling engine showing its simplicity. Unlike the steam engine or internal combustion engine, it has no valves or timing train. The heat source (not shown )  would be placed under the brass cylinder.

Stirling engine

Heat engine that is operated by the cyclic compression and expansion of air or other gas between different temperatures, resulting in a net conversion of heat energy to mechanical work.

Heat engine that is operated by the cyclic compression and expansion of air or other gas between different temperatures, resulting in a net conversion of heat energy to mechanical work.

A model of a Stirling engine showing its simplicity. Unlike the steam engine or internal combustion engine, it has no valves or timing train. The heat source (not shown )  would be placed under the brass cylinder.
Illustration from Robert Stirling's 1816 patent application of the air engine design that later came to be known as the Stirling Engine
A typical late nineteenth/early twentieth century water pumping engine by the Rider-Ericsson Engine Company
Philips MP1002CA Stirling generator of 1951
Stirling engine running
A pressure/volume graph of the idealized Stirling cycle.
Point focus parabolic mirror with Stirling engine at its centre and its solar tracker at Plataforma Solar de Almería (PSA) in Spain.
Alpha-type Stirling engine. There are two cylinders. The expansion cylinder (red) is maintained at a high temperature while the compression cylinder (blue) is cooled. The passage between the two cylinders contains the regenerator
Beta-type Stirling engine, with only one cylinder, hot at one end and cold at the other. A loose-fitting displacer shunts the air between the hot and cold ends of the cylinder. A power piston at the open end of the cylinder drives the flywheel
Top view of two rotating displacers powering the horizontal piston. Regenerators and radiator removed for clarity
Various free-piston Stirling configurations... F. "free cylinder", G. Fluidyne, H. "double-acting" Stirling (typically 4 cylinders).
Cutaway of the flat Stirling engine:
10 - Hot cylinder.
11 - A volume of hot cylinder.
12 - B volume of hot cylinder.
17 - Warm piston diaphragm.
18 - Heating medium.
19 - Piston rod.
20 - Cold cylinder.
21 - A Volume of cold cylinder.
22 - B Volume of cold cylinder.
27 - Cold piston diaphragm.
28 - Coolant medium.
30 - Working cylinder.
31 - A volume of working cylinder.
32 - B volume of working cylinder.
37 - Working piston diaphragm.
41 - Regenerator mass of A volume.
42 - Regenerator mass of B volume.
48 - Heat accumulator.
50 - Thermal insulation.
60 - Generator.
63 - Magnetic circuit.
64 - Electrical winding.
70 - Channel connecting warm and working cylinders.
A modern Stirling engine and generator set with 55 kW electrical output, for combined heat and power applications.
Dish Stirling from SES

In a free-piston device, energy may be added or removed by an electrical linear alternator, pump or other coaxial device.

A Haitian boy turns the crank on his crank-powered flashlight radio. Mechanically powered flashlights were distributed by aid organizations to survivors of the 2010 Haiti earthquake since electric power was lost for a long period.

Mechanically powered flashlight

Flashlight that is powered by electricity generated by the muscle power of the user, so it does not need replacement of batteries, or recharging from an electrical source.

Flashlight that is powered by electricity generated by the muscle power of the user, so it does not need replacement of batteries, or recharging from an electrical source.

A Haitian boy turns the crank on his crank-powered flashlight radio. Mechanically powered flashlights were distributed by aid organizations to survivors of the 2010 Haiti earthquake since electric power was lost for a long period.
A linear induction flashlight is charged by shaking it along its long axis, causing a magnet (visible at right) to slide through a coil of wire (center) to generate electricity.
German dynamo flashlight from World War I. Pulling the pull-chain spun a flywheel, generating electricity to light the bulb on the front for about 5 seconds.

This design contains a linear electrical generator which charges a supercapacitor which functions similarly to a rechargeable battery when the flashlight is shaken lengthwise.

Index of electrical engineering articles

Alphabetical list of articles pertaining specifically to electrical and electronics engineering.

Alphabetical list of articles pertaining specifically to electrical and electronics engineering.

Linear alternator

Free-piston engine used as a gas generator to drive a turbine

Free-piston engine

Free-piston engine used as a gas generator to drive a turbine
Figure 1 of US1657641

A free-piston engine is a linear, 'crankless' internal combustion engine, in which the piston motion is not controlled by a crankshaft but determined by the interaction of forces from the combustion chamber gases, a rebound device (e.g., a piston in a closed cylinder) and a load device (e.g. a gas compressor or a linear alternator).

Freebody diagram; modeling the interaction of the piston with the case

Thermomechanical generator

Abbreviation for "Thermo-Mechanical Generator", was invented in 1967 by E. H. Cooke-Yarborough at the Harwell Labs of the United Kingdom Atomic Energy Authority.

Abbreviation for "Thermo-Mechanical Generator", was invented in 1967 by E. H. Cooke-Yarborough at the Harwell Labs of the United Kingdom Atomic Energy Authority.

Freebody diagram; modeling the interaction of the piston with the case

This allows the displacer to be driven by positive feedback from the motion of the power piston and the magnets in the linear-alternator magnets, which have a combined weight of 10 kg.

Lorentz force acting on fast-moving charged particles in a bubble chamber. Positive and negative charge trajectories curve in opposite directions.

Lorentz force

Combination of electric and magnetic force on a point charge due to electromagnetic fields.

Combination of electric and magnetic force on a point charge due to electromagnetic fields.

Lorentz force acting on fast-moving charged particles in a bubble chamber. Positive and negative charge trajectories curve in opposite directions.
Lorentz' theory of electrons. Formulas for the Lorentz force (I, ponderomotive force) and the Maxwell equations for the divergence of the electrical field E (II) and the magnetic field B (III), La théorie electromagnétique de Maxwell et son application aux corps mouvants, 1892, p. 451. V is the velocity of light.
Charged particle drifts in a homogeneous magnetic field. (A) No disturbing force (B) With an electric field, E (C) With an independent force, F (e.g. gravity) (D) In an inhomogeneous magnetic field, grad H
Right-hand rule for a current-carrying wire in a magnetic field B
Lorentz force -image on a wall in Leiden
Lorentz force -image on a wall in Leiden

Linear alternators

A startup ecosystem can contribute to local entrepreneurial culture.

Vortex Bladeless

Spanish technology startup company that is developing a type of wind power generator without rotating blades or lubricants, unlike the more common wind turbines.

Spanish technology startup company that is developing a type of wind power generator without rotating blades or lubricants, unlike the more common wind turbines.

A startup ecosystem can contribute to local entrepreneurial culture.

A linear alternator transforms mechanical energy into electricity.

Wave Power Station using a pneumatic Chamber

Wave power

Capture of energy of wind waves to do useful work – for example, electricity generation, water desalination, or pumping water.

Capture of energy of wind waves to do useful work – for example, electricity generation, water desalination, or pumping water.

Wave Power Station using a pneumatic Chamber
Simplified design of Wave Power Station
When an object bobs up and down on a ripple in a pond, it follows approximately an elliptical trajectory.
Photograph of the elliptical trajectories of water particles under a – progressive and periodic – surface gravity wave in a wave flume. The wave conditions are: mean water depth d = 2.50 ft, wave height H = 0.339 ft, wavelength λ = 6.42 ft, period T = 1.12 s.
Generic wave energy concepts: 1. Point absorber, 2. Attenuator, 3. Oscillating wave surge converter, 4. Oscillating water column, 5. Overtopping device, 6. Submerged pressure differential, 7. Floating in-air converters.
World wave energy resource map

Buoys use the rise and fall of swells to generate electricity in various ways including directly via linear generators, or via generators driven by mechanical linear-to-rotary converters or hydraulic pumps.

Stelzer engine

Stelzer engine

Two-stroke opposing-piston free-piston engine design proposed by Frank Stelzer.

Two-stroke opposing-piston free-piston engine design proposed by Frank Stelzer.

Stelzer engine

A linear generator