301:
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222:
208:
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215:
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240:
27:
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195:, on the winding to make it turn. In a generator, the mechanical torque applied to the shaft maintains the motion of the armature winding through the stationary magnetic field, inducing a current in the winding. In both the motor and generator case, the commutator periodically reverses the direction of current flow through the winding so that current flow in the circuit external to the machine continues in only one direction.
349:
it ramps down more smoothly than had been the case with pure copper brushes where the contact broke suddenly. Similarly the segment coming into contact with the brush has a similar ramping up of the current. Thus, although the current passing through the brush was more or less constant, the instantaneous current passing to the two commutator segments was proportional to the relative area in contact with the brush.
231:
three segments, although the rotor can potentially stop in a position where two commutator segments touch one brush, this only de-energizes one of the rotor arms while the others will still function correctly. With the remaining rotor arms, a motor can produce sufficient torque to begin spinning the rotor, and a generator can provide useful power to an external circuit.
440:
451:. To conduct sufficient current to or from the commutator, the brush contact area is not a thin line but instead a rectangular patch across the segments. Typically the brush is wide enough to span 2.5 commutator segments. This means that two adjacent segments are electrically connected by the brush when it contacts both.
596:
Due to friction, the brushes and copper commutator segments wear down, creating dust. In small consumer products such as power tools and appliances the brushes may last as long as the product, but larger machines require regular replacement of brushes and occasional resurfacing of the commutator. So
550:
To minimize sparking at the brushes due to this short-circuiting, the brushes are advanced a few degrees further yet, beyond the advance for field distortions. This moves the rotor winding undergoing commutation slightly forward into the stator field which has magnetic lines in the opposite direction
512:
These field effects are reversed when the direction of spin is reversed. It is therefore difficult to build an efficient reversible commutated dynamo, since for highest field strength it is necessary to move the brushes to the opposite side of the normal neutral plane. These effects can be mitigated
397:
Modern devices using carbon brushes usually have a maintenance-free design that requires no adjustment throughout the life of the device, using a fixed-position brush holder slot and a combined brush-spring-cable assembly that fits into the slot. The worn brush is pulled out and a new brush inserted.
385:
High power, high current commutated equipment is now uncommon, due to the less complex design of alternating current generators that permits a low current, high voltage spinning field coil to energize high current fixed-position stator coils. This permits the use of very small singular brushes in the
381:
When a commutated motor or generator uses more power than a single brush is capable of conducting, an assembly of several brush holders is mounted in parallel across the surface of the very large commutator. This parallel holder distributes current evenly across all the brushes, and permits a careful
288:
Friction between the segments and the brushes eventually causes wear to both surfaces. Carbon brushes, being made of a softer material, wear faster and may be designed to be replaced easily without dismantling the machine. Older copper brushes caused more wear to the commutator, causing deep grooving
356:
The ratio of copper to carbon can be changed for a particular purpose. Brushes with higher copper content perform better with very low voltages and high current, while brushes with a higher carbon content are better for high voltage and low current. High copper content brushes typically carry 150 to
344:
Various developments took place to automate the process of adjusting the commutation and minimizing the sparking at the brushes. One of these was the development of 'high resistance brushes', or brushes made from a mixture of copper powder and carbon. Although described as high resistance brushes,
336:
Modern rotating machines with commutators almost exclusively use carbon brushes, which may have copper powder mixed in to improve conductivity. Metallic copper brushes can be found in toy or very small motors, such as the one illustrated above, and some motors which only operate very intermittently,
230:
Practical commutators have at least three contact segments, to prevent a "dead" spot where two brushes simultaneously bridge only two commutator segments. Brushes are made wider than the insulated gap, to ensure that brushes are always in contact with an armature coil. For commutators with at least
662:
One variety, notable for having an adjustable speed, runs continuously with brushes in contact, while another uses repulsion only for high starting torque and in some cases lifts the brushes once the motor is running fast enough. In the latter case, all commutator segments are connected together as
508:
The faster the rotor spins, the further this degree of field distortion. Because a motor or generator operates most efficiently with the rotor field at right angles to the stator field, it is necessary to either retard or advance the brush position to put the rotor's field into the correct position
373:
A spring is typically used with the brush, to maintain constant contact with the commutator. As the brush and commutator wear down, the spring steadily pushes the brush downwards towards the commutator. Eventually the brush wears small and thin enough that steady contact is no longer possible or it
348:
The high resistance or carbon brush is made large enough that it is significantly wider than the insulating segment that it spans (and on large machines may often span two insulating segments). The result of this is that as the commutator segment passes from under the brush, the current passing to
190:
A commutator consists of a set of contact bars fixed to the rotating shaft of a machine, and connected to the armature windings. As the shaft rotates, the commutator reverses the flow of current in a winding. For a single armature winding, when the shaft has made one-half complete turn, the winding
430:
The softness of carbon brushes permits direct radial end-contact with the commutator without damage to the segments, permitting easy reversal of rotor direction, without the need to reorient the brush holders for operation in the opposite direction. Although never reversed, common appliance motors
352:
The introduction of the carbon brush had convenient side effects. Carbon brushes tend to wear more evenly than copper brushes, and the soft carbon causes far less damage to the commutator segments. There is less sparking with carbon as compared to copper, and as the carbon wears away, the higher
340:
Motors and generators suffer from a phenomenon known as 'armature reaction', one of the effects of which is to change the position at which the current reversal through the windings should ideally take place as the loading varies. Early machines had the brushes mounted on a ring that was provided
272:
In small appliance and tool motors the segments are typically crimped permanently in place and cannot be removed. When the motor fails it is discarded and replaced. On large industrial machines (say, from several kilowatts to thousands of kilowatts in rating) it is economical to replace individual
467:
Most introductions to motor and generator design start with a simple two-pole device with the brushes arranged at a perfect 90-degree angle from the field. This ideal is useful as a starting point for understanding how the fields interact but it is not how a motor or generator functions in actual
284:
In addition to the commonly used heat, torque, and tonnage methods of seasoning commutators, some high performance commutator applications require a more expensive, specific "spin seasoning" process or over-speed spin-testing to guarantee stability of the individual segments and prevent premature
658:
These are single-phase AC-only motors with higher starting torque than could be obtained with split-phase starting windings, before high-capacitance (non-polar, relatively high-current electrolytic) starting capacitors became practical. They have a conventional wound stator as with any induction
332:
Early machines used brushes made from strands of copper wire to contact the surface of the commutator. However, these hard metal brushes tended to scratch and groove the smooth commutator segments, eventually requiring resurfacing of the commutator. As the copper brushes wore away, the dust and
426:
The different brush types make contact with the commutator in different ways. Because copper brushes have the same hardness as the commutator segments, the rotor cannot be spun backwards against the ends of copper brushes without the copper digging into the segments and causing severe damage.
276:
Replacing the copper and mica segments is commonly referred to as "refilling". Refillable dovetailed commutators are the most common construction of larger industrial type commutators, but refillable commutators may also be constructed using external bands made of fiberglass (glass banded
258:
Commutator segments are connected to the coils of the armature, with the number of coils (and commutator segments) depending on the speed and voltage of the machine. Large motors may have hundreds of segments. Each conducting segment of the commutator is insulated from adjacent segments.
345:
the resistance of such a brush was of the order of milliohms, the exact value dependent on the size and function of the machine. Also, the high resistance brush was not constructed like a brush but in the form of a carbon block with a curved face to match the shape of the commutator.
570:
By applying a dynamic varying field to the interpoles as the load, RPM, or direction of rotation of the device changes, it is possible to balance out field distortions from armature reaction so that the brush position can remain fixed and sparking across the segments is minimized.
292:
The commutator on small motors (say, less than a kilowatt rating) is not designed to be repaired through the life of the device. On large industrial equipment, the commutator may be re-surfaced with abrasives, or the rotor may be removed from the frame, mounted in a large metal
333:
pieces of the brush could wedge between commutator segments, shorting them and reducing the efficiency of the device. Fine copper wire mesh or gauze provided better surface contact with less segment wear, but gauze brushes were more expensive than strip or wire copper brushes.
608:
There is a limit to the maximum current density and voltage which can be switched with a commutator. Very large direct current machines, say, more than several megawatts rating, cannot be built with commutators. The largest motors and generators are all alternating-current
604:
of the sliding contact between brush and commutator causes a voltage drop called the "brush drop". This may be several volts, so it can cause large power losses in low voltage, high current machines. Alternating current motors, which do not use commutators, are much more
540:
In the coils of the rotor, even after the brush has been reached, currents tend to continue to flow for a brief moment, resulting in a wasted energy as heat due to the brush spanning across several commutator segments and the current short-circuiting across the segments.
357:
200 amperes per square inch of contact surface, while higher carbon content only carries 40 to 70 amperes per square inch. The higher resistance of carbon also results in a greater voltage drop of 0.8 to 1.0 volts per contact, or 1.6 to 2.0 volts across the commutator.
520:
The effect can be considered to be analogous to timing advance in an internal combustion engine. Generally a dynamo that has been designed to run at a certain fixed speed will have its brushes permanently fixed to align the field for highest efficiency at that speed.
431:
that use wound rotors, commutators and brushes have radial-contact brushes. In the case of a reaction-type carbon brush holder, carbon brushes may be reversely inclined with the commutator so that the commutator tends to push against the carbon for firm contact.
659:
motor, but the wire-wound rotor is much like that with a conventional commutator. Brushes opposite each other are connected to each other (not to an external circuit), and transformer action induces currents into the rotor that develop torque by repulsion.
554:
So even for a rotor which is at rest and initially requires no compensation for spinning field distortions, the brushes should still be advanced beyond the perfect 90-degree angle as taught in so many beginners textbooks, to compensate for self-induction.
427:
Consequently, strip/laminate copper brushes only make tangential contact with the commutator, while copper mesh and wire brushes use an inclined contact angle touching their edge across the segments of a commutator that can spin in only one direction.
583:
Low-voltage dynamo from late 1800s for electroplating. The resistance of the commutator contacts causes inefficiency in low-voltage, high-current machines such as this, requiring a huge elaborate commutator. This machine generated 7 volts at 310
263:
was used on early machines and is still used on large machines. Many other insulating materials are used to insulate smaller machines; plastics allow quick manufacture of an insulator, for example. The segments are held onto the shaft using a
422:; 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.
285:
wear of the carbon brushes. Such requirements are common with traction, military, aerospace, nuclear, mining, and high speed applications where clamping failure and segment or insulation protrusion can lead to serious negative consequences.
377:
It is common for a flexible power cable to be directly attached to the brush, because current flowing through the support spring would cause heating, which may lead to a loss of metal temper and a loss of the spring tension.
496:
In a real motor or generator, the field around the rotor is never perfectly uniform. Instead, the rotation of the rotor induces field effects which drag and distort the magnetic lines of the outer non-rotating stator.
280:
Disposable, molded type commutators commonly found in smaller DC motors are becoming increasingly more common in larger electric motors. Molded type commutators are not repairable and must be replaced if damaged.
268:
shape on the edges or underside of each segment. Insulating wedges around the perimeter of each segment are pressed so that the commutator maintains its mechanical stability throughout its normal operating range.
588:
Although direct current motors and dynamos once dominated industry, the disadvantages of the commutator have caused a decline in the use of commutated machines in the last century. These disadvantages are:
341:
with a handle. During operation, it was necessary to adjust the position of the brush ring to adjust the commutation to minimise the sparking at the brushes. This process was known as 'rocking the brushes'.
537:
Self-induction – The magnetic fields in each coil of wire join and compound together to create a magnetic field that resists changes in the current, which can be likened to the current having inertia.
184:
809:
191:
is now connected so that current flows through it in the opposite of the initial direction. In a motor, the armature current causes the fixed magnetic field to exert a rotational force, or a
136:) is produced. In a generator the commutator picks off the current generated in the windings, reversing the direction of the current with each half turn, serving as a mechanical
640:". These don't have a commutator; instead the direction of the current is switched electronically. A sensor keeps track of the rotor position and semiconductor switches such as
163:
Commutators are relatively inefficient, and also require periodic maintenance such as brush replacement. Therefore, commutated machines are declining in use, being replaced by
255:
fixed to the stationary frame of the machine. Two or more fixed brushes connect to the external circuit, either a source of current for a motor or a load for a generator.
710:
wires. The output is taken from a pair of curved copper wires which are moved to dip into one or other pair of mercury wells. Instead of mercury, ionic liquids or other
297:, and the commutator resurfaced by cutting it down to a smaller diameter. The largest of equipment can include a lathe turning attachment directly over the commutator.
547:
is an apparent increase in the resistance in the armature winding, which is proportional to the speed of the armature, and is due to the lagging of the current.
666:
Once at speed, the rotor windings become functionally equivalent to the squirrel-cage structure of a conventional induction motor, and the motor runs as such.
674:
Commutators were used as simple forward-off-reverse switches for electrical experiments in physics laboratories. There are two well-known historical types:
490:
On the left is an exaggerated example of how the field is distorted by the rotor. On the right, iron filings show the distorted field across the rotor.
841:
105:
press against the commutator, making sliding contact with successive segments of the commutator as it rotates. The windings (coils of wire) on the
597:
commutated machines are not used in low particulate or sealed applications or in equipment that must operate for long periods without maintenance.
1114:
1089:
89:
direction between the rotor and the external circuit. It consists of a cylinder composed of multiple metal contact segments on the rotating
1442:
1186:
1158:
1151:
277:
construction) or forged steel rings (external steel shrink ring type construction and internal steel shrink ring type construction).
382:
operator to remove a bad brush and replace it with a new one, even as the machine continues to spin fully powered and under load.
551:
and which oppose the field in the stator. This opposing field helps to reverse the lagging self-inducting current in the stator.
1840:
593:
The sliding friction between the brushes and commutator consumes power, which can be significant in a low power machine.
567:, which are small field coils and pole pieces positioned approximately halfway between the primary poles of the stator.
1845:
251:
segments, fixed around the part of the circumference of the rotating machine, or the rotor, and a set of spring-loaded
132:
to the windings. By reversing the current direction in the rotating windings each half turn, a steady rotating force (
727:
300:
106:
90:
1622:
1179:
563:
Modern motor and generator devices with commutators are able to counteract armature reaction through the use of
1835:
1571:
1356:
1704:
617:
365:
1714:
1427:
1400:
637:
168:
1724:
1719:
1172:
682:
This is similar in design to the commutators used in motors and dynamos. It was usually constructed of
644:
reverse the current. Operating life of these machines is much longer, limited mainly by bearing wear.
1118:
1093:
273:
damaged segments, and so the end-wedge can be unscrewed and individual segments removed and replaced.
1799:
1417:
1395:
1033:, Theo. Audel and Co., 2nd ed. 1917, vol. 1, ch. 20: Commutation and the Commutator, p. 287, fig. 303
1009:, Theo. Audel and Co., 2nd ed. 1917, vol. 1, ch. 20: Commutation and the Commutator, p. 286, fig. 302
997:, Theo. Audel and Co., 2nd ed. 1917, vol. 1, ch. 20: Commutation and the Commutator, p. 265, fig. 287
985:, Theo. Audel and Co., 2nd ed. 1917, vol. 1, ch. 20: Commutation and the Commutator, p. 264, fig. 286
973:, Theo. Audel and Co., 2nd ed. 1917, vol. 1, ch. 20: Commutation and the Commutator, p. 285, fig. 301
961:, Theo. Audel and Co., 2nd ed. 1917, vol. 1, ch. 20: Commutation and the Commutator, p. 284, fig. 300
901:, Theo. Audel and Co., 2nd ed. 1917, vol. 1, ch. 21: Brushes and the Brush Gear, p. 304, fig. 329-332
763:
624:
With the wide availability of alternating current, DC motors have been replaced by more efficient AC
369:
Compound carbon brush holder, with individual clamps and tension adjustments for each block of carbon
353:
resistance of carbon results in fewer problems from the dust collecting on the commutator segments.
1830:
1668:
1522:
1030:
1018:
1006:
994:
982:
970:
958:
946:
934:
922:
898:
886:
1769:
1143:
1709:
1260:
949:, Theo. Audel and Co., 2nd ed. 1917, vol. 1, ch. 21: Brushes and the Brush Gear, p. 312, fig. 339
937:, Theo. Audel and Co., 2nd ed. 1917, vol. 1, ch. 21: Brushes and the Brush Gear, p. 307, fig. 335
889:, Theo. Audel and Co., 2nd ed. 1917, vol. 1, ch. 21: Brushes and the Brush Gear, p. 300, fig. 327
475:
157:
1532:
1437:
1366:
1021:, Theo. Audel and Co., 2nd ed. 1917, vol. 1, ch. 20: Commutation and the Commutator, p. 285-287
579:
500:
1663:
1527:
1245:
1043:
601:
482:
86:
47:
221:
207:
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1275:
732:
514:
82:
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8:
1764:
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1207:
439:
214:
164:
141:
94:
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1683:
1638:
1576:
1546:
1500:
1323:
1310:
925:, Theo. Audel and Co., 2nd ed. 1917, vol. 1, ch. 21: Brushes and the Brush Gear, p. 313
758:
459:
1749:
1653:
1581:
1373:
1361:
1351:
1059:"FEEE - Fundamentals of Electrical Engineering and Electronics: AC commutator motors"
703:
625:
414:
148:
in the external load circuit. The first direct current commutator-type machine, the
1699:
463:
Centered position of the commutating plane if there were no field distortion effects
1804:
1794:
1734:
1678:
1648:
1596:
1492:
1482:
1472:
1422:
1285:
1255:
1195:
748:
406:
374:
is no longer securely held in the brush holder, and so the brush must be replaced.
252:
129:
98:
1739:
1779:
1729:
1591:
1412:
1390:
1378:
1346:
1250:
768:
653:
629:
183:
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125:
31:
1754:
1774:
1673:
1643:
1505:
1457:
1405:
1333:
1270:
1213:
636:, in many remaining applications commutated DC motors have been replaced with "
616:
at the contacts, posing a fire hazard in explosive atmospheres, and generating
419:
145:
113:
78:
1058:
239:
19:
This article is about the electrical component. For mathematical concept, see
1824:
1784:
1452:
862:
846:
830:
814:
798:
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753:
633:
447:
The contact point where a brush touches the commutator is referred to as the
390:
design. In this instance, the rotating contacts are continuous rings, called
309:
294:
172:
26:
1809:
1744:
1432:
857:
825:
711:
613:
504:
Actual position of the commutating plane to compensate for field distortion
1586:
1517:
324:
702:
This consists of a block of wood or ebonite with four wells, containing
1477:
1447:
1318:
1280:
1161:
Commutation
Alignment – How It Is Accomplished." Mitchell Electronics.
641:
387:
20:
1759:
1512:
1290:
743:
715:
391:
304:
A tiny five-segment commutator less than 2 mm in diameter, on a
137:
1164:
1154:
Commutation
Alignment – Why It Is Important." Mitchell Electronics.
1541:
1385:
1341:
738:
305:
265:
121:
454:
1617:
1612:
1147:". HyperPhysics, Physics and Astronomy, Georgia State University.
691:
558:
312:
243:
Cross-section of a commutator that can be disassembled for repair
1295:
1219:
707:
410:
Different types of brushes have different brush contact angles.
248:
192:
149:
133:
117:
102:
74:
54:
632:. In recent years, with the widespread availability of power
1159:
PM Brushless Servo Motor
Feedback Commutation Series – Part 2
1152:
PM Brushless Servo Motor
Feedback Commutation Series – Part 1
687:
683:
517:
in the face of the field pole that carries armature current.
260:
524:
1044:"Interpole - an overview | ScienceDirect Topics"
1443:
Dual-rotor permanent magnet induction motor (DRPMIM)
820:Commutator For Dynamo or Magneto Electric Machines
1822:
198:
574:
509:to be at a right angle to the distorted field.
455:Rotation of brushes for stator field distortion
663:well, before the motor attains running speed.
612:The switching action of the commutator causes
559:Use of interpoles to correct field distortions
1180:
647:
234:
1187:
1173:
328:Various types of copper and carbon brushes
109:are connected to the commutator segments.
101:" made of a soft conductive material like
669:
178:
1115:"Fondazione Scienza e Tecnica - Firenze"
1090:"Fondazione Scienza e Tecnica - Firenze"
804:Commutator for Magneto Electric Machines
791:Commutators for Dynamo Electric Machines
578:
528:
499:
458:
438:
434:
413:
405:
364:
323:
299:
238:
182:
25:
16:Device for changing direction of current
868:Commutator for Dynamo Electric Machines
852:Commutator for Dynamo-Electric Machines
836:Commutator for Dynamo Electric Machines
677:
525:Further compensation for self-induction
289:and notching of the surface over time.
1823:
1077:Magnetism and Electricity for Students
810:Frank. B. Rae & Clarence. L. Healy
401:
167:(AC) machines, and in recent years by
1194:
1168:
1079:, MacMillan, London, 1905, pp 245-247
1056:
319:
144:from the windings to unidirectional
128:. In a motor the commutator applies
418:Commutator and brush assembly of a
337:such as automotive starter motors.
13:
1144:Commutator and Brushes on DC Motor
697:
247:A commutator consists of a set of
156:in 1832, based on a suggestion by
14:
1857:
1135:
728:Armature (electrical engineering)
533:Brush advance for self-induction
481:
474:
360:
220:
213:
206:
1107:
1082:
1069:
1050:
1036:
1024:
1012:
1000:
988:
910:Higher Electrical Engineering:
706:, which are cross connected by
638:brushless direct current motors
85:that periodically reverses the
1572:Timeline of the electric motor
976:
964:
952:
940:
928:
916:
904:
892:
880:
34:from a vacuum cleaner. Parts:
1:
1357:Dahlander pole changing motor
912:Shepherd, Morton & Spence
874:
443:Commutating plane definitions
199:Simplest practical commutator
618:electromagnetic interference
575:Limitations and alternatives
394:, and no switching happens.
93:of the machine. Two or more
7:
1841:Electrical power connectors
1401:Brushless DC electric motor
721:
10:
1862:
774:
651:
648:Repulsion induction motors
18:
1846:Electric power conversion
1692:
1631:
1605:
1560:
1491:
1418:Switched reluctance (SRM)
1396:Brushed DC electric motor
1332:
1309:
1234:
1202:
764:Mercury swivel commutator
489:
235:Ring/segment construction
120:(DC generators) and many
1606:Experimental, futuristic
1523:Variable-frequency drive
1031:Hawkins Electrical Guide
1019:Hawkins Electrical Guide
1007:Hawkins Electrical Guide
995:Hawkins Electrical Guide
983:Hawkins Electrical Guide
971:Hawkins Electrical Guide
959:Hawkins Electrical Guide
947:Hawkins Electrical Guide
935:Hawkins Electrical Guide
923:Hawkins Electrical Guide
899:Hawkins Electrical Guide
887:Hawkins Electrical Guide
112:Commutators are used in
1623:Superconducting machine
1261:Coil winding technology
65:electrical connections.
670:Laboratory commutators
585:
534:
505:
464:
444:
423:
411:
370:
329:
316:
244:
187:
179:Principle of operation
66:
1836:Electrical components
1664:Power-to-weight ratio
1528:Direct torque control
582:
532:
503:
462:
442:
435:The commutating plane
417:
409:
368:
327:
303:
242:
186:
83:electrical generators
29:
1659:Open-loop controller
1552:Ward Leonard control
1276:DC injection braking
733:Floor pick-up system
678:Ruhmkorff commutator
515:compensation winding
306:direct-current motor
77:in certain types of
1562:History, education,
1208:Alternating current
863:U.S. patent 382,845
847:U.S. patent 340,537
831:U.S. patent 334,823
822:- 1884 February 26.
815:U.S. patent 294,270
806:- 1881 September 6.
799:U.S. patent 246,612
786:U.S. patent 242,488
545:Spurious resistance
402:Brush contact angle
169:brushless DC motors
165:alternating current
142:alternating current
95:electrical contacts
1725:Dolivo-Dobrovolsky
1684:Voltage controller
1639:Blocked-rotor test
1577:Ball bearing motor
1547:Motor soft starter
1501:AC-to-AC converter
1362:Wound-rotor (WRIM)
1324:Electric generator
838:- 1886 January 26.
759:Rotary transformer
586:
535:
506:
465:
445:
424:
412:
371:
330:
320:Brush construction
317:
245:
188:
158:André-Marie Ampère
67:
57:(field) windings,
1818:
1817:
1654:Open-circuit test
1493:Motor controllers
1374:Synchronous motor
1196:Electric machines
494:
493:
449:commutating plane
228:
227:
75:electrical switch
1853:
1669:Two-phase system
1649:Electromagnetism
1597:Mouse mill motor
1564:recreational use
1438:Permanent magnet
1367:Linear induction
1220:Permanent magnet
1189:
1182:
1175:
1166:
1165:
1130:
1129:
1127:
1126:
1117:. Archived from
1111:
1105:
1104:
1102:
1101:
1092:. Archived from
1086:
1080:
1073:
1067:
1066:
1054:
1048:
1047:
1040:
1034:
1028:
1022:
1016:
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944:
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932:
926:
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914:
908:
902:
896:
890:
884:
865:
854:- 1886 April 27.
849:
833:
817:
801:
788:
749:Reversing switch
630:induction motors
485:
478:
471:
470:
224:
217:
210:
203:
202:
130:electric current
126:universal motors
30:Commutator in a
1861:
1860:
1856:
1855:
1854:
1852:
1851:
1850:
1831:Electric motors
1821:
1820:
1819:
1814:
1688:
1627:
1601:
1592:Mendocino motor
1565:
1563:
1556:
1487:
1347:Induction motor
1328:
1305:
1251:Braking chopper
1239:
1237:
1230:
1198:
1193:
1138:
1133:
1124:
1122:
1113:
1112:
1108:
1099:
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1088:
1087:
1083:
1075:Hadley, H. E.,
1074:
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1005:
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909:
905:
897:
893:
885:
881:
877:
861:
845:
842:Thomas E. Adams
829:
813:
797:
796:Henry Jacobs -
784:
777:
769:Brushless motor
724:
700:
698:Pohl commutator
680:
672:
656:
654:Repulsion motor
650:
577:
561:
527:
457:
437:
404:
363:
322:
237:
201:
181:
154:Hippolyte Pixii
152:, was built by
140:to convert the
116:(DC) machines:
79:electric motors
32:universal motor
24:
17:
12:
11:
5:
1859:
1849:
1848:
1843:
1838:
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1816:
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1712:
1707:
1702:
1696:
1694:
1690:
1689:
1687:
1686:
1681:
1676:
1674:Inchworm motor
1671:
1666:
1661:
1656:
1651:
1646:
1644:Circle diagram
1641:
1635:
1633:
1632:Related topics
1629:
1628:
1626:
1625:
1620:
1615:
1609:
1607:
1603:
1602:
1600:
1599:
1594:
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1582:Barlow's wheel
1579:
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1558:
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1539:
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1535:
1533:Vector control
1530:
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1510:
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1506:Cycloconverter
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1236:Components and
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1214:Direct current
1210:
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1199:
1192:
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1155:
1148:
1137:
1136:External links
1134:
1132:
1131:
1106:
1081:
1068:
1057:Lohninger, H.
1049:
1035:
1023:
1011:
999:
987:
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939:
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903:
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870:- 1888 May 15.
855:
839:
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793:- 1881 June 7.
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420:traction motor
403:
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362:
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321:
318:
236:
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146:direct current
114:direct current
61:brush guides,
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1468:Piezoelectric
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1463:Electrostatic
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1139:
1121:on 2011-07-22
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1096:on 2011-07-22
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781:Elihu Thomson
779:
778:
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755:
754:Rotary switch
752:
750:
747:
745:
742:
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734:
731:
729:
726:
725:
719:
718:can be used.
717:
713:
712:liquid metals
709:
705:
695:
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310:radio-control
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173:semiconductor
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60:
56:
53:
49:
45:
41:
37:
33:
28:
22:
1265:
1225:
1142:
1123:. Retrieved
1119:the original
1109:
1098:. Retrieved
1094:the original
1084:
1076:
1071:
1063:www.vias.org
1062:
1052:
1038:
1026:
1014:
1002:
990:
978:
966:
954:
942:
930:
918:
911:
906:
894:
882:
867:
858:Nikola Tesla
851:
835:
826:Nikola Tesla
819:
803:
790:
701:
681:
673:
665:
661:
657:
623:
587:
569:
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189:
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111:
73:is a rotary
70:
68:
62:
58:
51:
50:) windings,
43:
39:
38:commutator,
35:
1587:Lynch motor
1352:Shaded-pole
1238:accessories
642:transistors
626:synchronous
175:switches.
124:as well as
1825:Categories
1483:Axial flux
1473:Ultrasonic
1448:Servomotor
1428:Doubly fed
1423:Reluctance
1319:Alternator
1311:Generators
1281:Field coil
1266:Commutator
1226:commutated
1224:SC - Self-
1125:2009-02-08
1100:2009-02-08
875:References
652:See also:
605:efficient.
602:resistance
565:interpoles
468:practice.
392:slip rings
388:alternator
171:which use
71:commutator
21:Commutator
1800:Steinmetz
1715:Davenport
1513:Amplidyne
1413:Universal
1391:Homopolar
1379:Repulsion
1291:Slip ring
744:Slip ring
716:galinstan
609:machines.
308:in a toy
138:rectifier
122:DC motors
1805:Sturgeon
1735:Ferraris
1720:Davidson
1542:Metadyne
1458:Traction
1406:Unipolar
1386:DC motor
1342:AC motor
1246:Armature
739:H-bridge
722:See also
714:such as
614:sparking
266:dovetail
107:armature
97:called "
91:armature
48:armature
1795:Sprague
1790:Siemens
1765:Maxwell
1730:Faraday
1679:Starter
1618:Railgun
1613:Coilgun
1453:Stepper
1301:Winding
775:Patents
704:mercury
692:ebonite
690:(later
313:ZipZaps
253:brushes
118:dynamos
99:brushes
87:current
46:rotor (
42:brush,
1785:Saxton
1770:Ørsted
1755:Jedlik
1750:Jacobi
1740:Gramme
1705:Barlow
1693:People
1518:Drives
1433:Linear
1334:Motors
1296:Stator
708:copper
249:copper
193:torque
150:dynamo
134:torque
103:carbon
55:stator
1810:Tesla
1780:Pixii
1745:Henry
1710:Botto
1700:Arago
1286:Rotor
1256:Brush
1218:PM -
1212:DC -
1206:AC -
735:(FPU)
688:ivory
684:brass
584:amps.
513:by a
295:lathe
1775:Park
1760:Lenz
1478:TEFC
686:and
600:The
261:Mica
81:and
694:).
628:or
315:car
63:(F)
59:(E)
52:(D)
44:(C)
40:(B)
36:(A)
1827::
1061:.
866:-
860:-
850:-
844:-
834:-
828:-
818:-
812:-
802:-
789:-
783:-
160:.
69:A
1188:e
1181:t
1174:v
1157:"
1150:"
1141:"
1128:.
1103:.
1065:.
1046:.
620:.
23:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
