20:
259:
331:
disconnected, no current reaches the field windings and the alternator will not generate power. Some warning indicator circuits are equipped with a resistor in parallel with the lamp that permit excitation current to flow if the warning lamp burns out. The driver should check that the warning indicator is on when the engine is stopped; otherwise, there might not be any indication of a failure of the belt which may also drive the cooling
267:
each end, and the airflow is semi-radial, entering axially and leaving radially outwards. The stator windings now consist of a dense central band where the iron core and copper windings are tightly packed, and end bands where the windings are more exposed for better heat transfer. The closer core spacing from the rotor improves magnetic efficiency. The smaller, enclosed fans produce less noise, particularly at higher machine speeds.
388:
239:
138:(There was a switch on the ignition coils to use a battery instead, which could be helpful when starting in cold weather, but Ford neither provided a battery nor did it encourage the use of one before it introduced an electric starter in 1919. The owner would have to install the battery themselves and charge it externally.)
134:, which generates high voltage directly.) Since such a magneto system only depended on the engine's motion to generate current, it could even be used when starting a manually cranked engine, provided the crank was pulled sharply, so that the magneto would produce enough current for the coils to make good sparks.
504:
and others, one may operate as a generator and feed the other as a motor, providing an electromechanical path for some of the engine power to flow to the wheels. These motor/generators have considerably more powerful electronic devices for their control than the automotive alternator described above.
373:
systems, which achieve an efficiency around 60%. Larger permanent magnet electric machines (that can operate as motors or alternators) can achieve today much higher efficiencies. Pellegrino et al., for instance, propose not particularly expensive designs that show ample regions in which efficiency is
368:
Efficiency of automotive alternators is limited by fan cooling loss, bearing loss, iron loss, copper loss, and the voltage drop in the diode bridges. Efficiency reduces dramatically at high speeds mainly due to fan resistance. At medium speeds efficiency of today's alternators is 70–80%. This betters
330:
feeds the field current from the alternator main output equalizing the voltage across the warning indicator which goes off. The wire supplying the field current is often referred to as the "exciter" wire. The drawback of this arrangement is that if the warning lamp burns out or the "exciter" wire is
266:
Modern vehicles now use the compact alternator layout. This is electrically and magnetically similar, but has improved air cooling. Better cooling permits more power from a smaller machine. The casing has distinctive radial vent slots at each end and now encloses the fan. Two fans are used, one at
137:
The Model T incorporated its magneto into the engine flywheel. The first Model Ts used the magneto solely for the trembler coil ignition. Beginning with the 1915 model year, Ford added electric headlights, also powered by the magneto. The magneto circuit was strictly AC, with no battery included.
317:
alternator may need only 2-3 A of field current. The field current is supplied to the rotor windings by slip rings. The low current and relatively smooth slip rings ensure greater reliability and longer life than that obtained by a DC generator with its commutator and higher current being passed
308:
which operates by modulating the small field current to produce a constant voltage at the battery terminals. Early designs (c.1960s–1970s) used a discrete device mounted elsewhere in the vehicle. Intermediate designs (c.1970s–1990s) incorporated the voltage regulator into the alternator housing.
229:
Alternator regulators are also simpler than those for generators. Generator regulators require a cutout relay to isolate the output coils (the armature) from the battery at low speed; that isolation is provided by the alternator rectifier diodes. Also, most generator regulators include a current
141:
Starting in the 1919 model year, Ford upgraded the Model T to include an electric starter, which was standard for some models and optional for others. This starter installation also included a battery, charged by a conventional dynamo, and the lights were now powered by the battery. However, the
254:
Typical passenger vehicle and light truck alternators use
Lundahl or 'claw-pole' field construction. This uses a shaped iron core on the rotor to produce a multi-pole field from a single coil winding. The poles of the rotor look like fingers of two hands interlocked with each other. The coil is
250:
Despite their names, both 'DC generators' (or 'dynamos') and 'alternators' initially produce alternating current. In a so-called 'DC generator', this AC current is generated in the rotating armature, and then converted to DC by the commutator and brushes. In an 'alternator', the AC current is
295:
Brushless versions of these type alternators are also common in larger machinery such as highway trucks and earthmoving machinery. With two oversized shaft bearings as the only wearing parts, these can provide extremely long and reliable service, even exceeding the engine overhaul intervals.
495:
replace the separate alternator and starter motor with one or more combined motor/generator(s) that start the internal combustion engine, provide some or all of the mechanical power to the wheels, and charge a large storage battery. When more than one motor/generator is present, as in the
338:
In recent years, alternator regulators are linked to the vehicle's computer system and various factors including air temperature obtained from the intake air temperature sensor, battery temperature sensor and engine load are evaluated in adjusting the voltage supplied by the alternator.
242:
Cut-away of an alternator, showing the claw-pole construction; two of the wedge-shaped field poles, alternating N and S, are visible in the centre and the stationary armature winding is visible at the top and bottom of the opening. The belt and pulley at the right-hand end drives the
218:-driven at 2–3 times crankshaft speed, speeds that could cause a commutator to fly apart in a generator. The alternator runs at various RPM (which varies the frequency) since it is driven by the engine. This is not a problem because the alternating current is
359:
and other electrical systems. Very large alternators used on buses, heavy equipment or emergency vehicles may produce 300 A. Semi-trucks usually have alternators which output 140 A. Very large alternators may be water-cooled or oil-cooled.
255:
mounted axially inside this and field current is supplied by slip rings and carbon brushes. These alternators have their field and stator windings cooled by axial airflow, produced by an external fan attached to the drive belt pulley.
325:
supplies the "charge" warning indicator and is earthed via the regulator (which is why the indicator is on when the ignition is on but the engine is not running). Once the engine is running and the alternator is generating power, a
760:
G. Pellegrino, A. Vagati, P. Guglielmi, "Performance
Comparison Between Surface-Mounted and Interior PM Motor Drives for Electric Vehicle Application" IEEE Transactions on industrial electronics, vol 59, No 2, February 2012 pag.
351:. Typical passenger car and light truck alternators are rated around 50–70 A, though higher ratings are becoming more common, especially as there is more load on the vehicle's electrical system with
85:, to power radio equipment on specialist vehicles. After the war, other vehicles with high electrical demands — such as ambulances and radio taxis — could also be fitted with optional alternators.
69:
gradually replaced the dynamo. This was encouraged by the increasing electrical power required for cars in this period, with increasing loads from larger headlamps, electric wipers,
374:
above 96%. Large AC generators used in power stations run at carefully controlled speeds and have no constraints on size or weight. They have very high efficiencies as high as 98%.
789:
782:
409:
186:
excitation current, which is a small fraction of the current carried by the brushes of a DC generator, which carry the generator's entire output
142:
flywheel magneto still powered the ignition, and since models without the starter had no battery, they continued to use magneto-powered lights.
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winding is used and the pole-pieces of the rotor are shaped (claw-pole). Automotive alternators are usually
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567:
309:
Modern designs do away with the voltage regulator altogether; voltage regulation is now a function of the
1116:
957:
176:
58:
313:(ECU). The field current is much smaller than the output current of the alternator; for example, a 70
130:, which provided the high voltage needed to generate ignition sparks. (This was different from a true
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1111:
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The field windings are supplied with power from the battery via the ignition switch and regulator. A
89:
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The claw pole design produces an AC waveform that is more efficiently rectified than a sine wave.
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Older automobiles with minimal lighting may have had an alternator capable of producing only 30
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generated in the stationary stator, and then is converted to DC by the rectifiers (diodes).
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The modern type of vehicle alternators were first used in military applications during
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Alternators were first introduced as standard equipment on a production car by the
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very small high-performance permanent magnet alternators, such as those used for
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335:. Some alternators will self-excite when the engine reaches a certain speed.
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Devices in automobiles to charge the battery and power the electrical system
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The windings of a 3 phase alternator may be connected using either the
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which generated low-voltage alternating current that was supplied to
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610:"Encyclopedia: 1915 and 1916 [comprehensive description]"
1362:
646:"Encyclopedia: 1917 to 1920 [comprehensive description]"
771:
809:
381:
122:, used a different sort of charging system: an engine-driven
153:
have several advantages over direct-current generators (
579:
Another
Chrysler "first" ... the amazing new alternator
65:
rectifiers became widely available and affordable, the
230:
limiter; alternators are inherently current-limited.
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270:Alternators can also be water-cooled in cars.
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8:
46:and to power the electrical system when its
416:. Unsourced material may be challenged and
790:
776:
768:
577:. Chrysler Corporation (Australia). 1962.
480:Learn how and when to remove this message
856:Crankcase ventilation system (PCV valve)
544:
542:
277:alternators similar to larger machines.
182:The brushes in an alternator carry only
538:
514:
164:Can provide useful charge at idle speed
743:, Robert Bosch GmbH, Stuttgart, 2011,
720:"Understanding 3 phase alternators..."
663:"Electrical System and Power Supply".
206:. To provide direct current with low
53:Until the 1960s, automobiles used DC
7:
706:
694:
414:adding citations to reliable sources
14:
304:Automotive alternators require a
179:(Or completely brushless designs)
161:Lighter, cheaper, and more rugged
118:Some early automobiles, like the
23:Alternator (silver) mounted on a
386:
96:in 1960, several years ahead of
958:Overhead valve (pushrod) layout
741:Automotive Handbook 8th Edition
1:
108:Magnetos in early automobiles
1457:Automotive charging circuits
650:Model T Ford Club of America
632:Model T Ford Club of America
614:Model T Ford Club of America
596:Model T Ford Club of America
575:Valiant promotional brochure
550:"Alternators and Generators"
429:"Alternator" automotive
292:) connection regime set-up.
1475:
799:Internal combustion engine
171:, having greatly extended
111:
1416:
1267:Diesel particulate filter
1219:Idle air control actuator
1160:Engine control unit (ECU)
805:
273:Larger vehicles may have
198:) is required to convert
73:, and other accessories.
1332:Viscous fan (fan clutch)
1244:Throttle position sensor
953:Overhead camshaft layout
671:. 1993. pp. 770–1.
493:Hybrid electric vehicles
871:Core plug (freeze plug)
357:electric power steering
146:Advantages over dynamos
263:
244:
27:
1452:Electrical generators
568:"Valiant by Chrysler"
318:through its brushes.
261:
241:
22:
1112:Compression ignition
628:"Encyclopedia: 1919"
592:"Encyclopedia: 1915"
498:Hybrid Synergy Drive
410:improve this section
157:). Alternators are:
90:Chrysler Corporation
1262:Catalytic converter
665:Automotive Handbook
523:Fitted For Wireless
311:engine control unit
71:heated rear windows
1388:Knocking / pinging
980:Combustion chamber
739:Horst Bauer (ed.)
709:, pp. 771–772
264:
262:Compact alternator
245:
36:electric generator
28:
1434:
1433:
1403:Stratified charge
1170:Electrical system
1152:Engine management
985:Compression ratio
925:Starter ring gear
824:rotating assembly
749:978-0-8376-1686-5
490:
489:
482:
464:
306:voltage regulator
1464:
1277:Exhaust manifold
1142:Spark plug wires
1028:Boost controller
1015:Forced induction
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722:windstuffnow.com
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667:(3rd ed.).
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371:bicycle lighting
353:air conditioning
323:parallel circuit
300:Field regulation
132:ignition magneto
57:generators with
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38:used in modern
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224:direct current
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128:trembler coils
112:Main article:
109:
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102:General Motors
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42:to charge the
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1059:Diesel engine
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395:This section
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63:silicon-diode
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37:
34:is a type of
33:
26:
21:
1317:Electric fan
1177:
1117:Coil-on-plug
1043:Turbocharger
1038:Supercharger
910:Main bearing
900:Firing order
890:Displacement
836:Block heater
820:Engine block
808:Part of the
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120:Ford Model T
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83:World War II
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50:is running.
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1447:Alternators
1341:Lubrication
1305:Air cooling
1122:Distributor
1074:Fuel filter
1052:Fuel system
1033:Intercooler
1000:Timing belt
990:Head gasket
920:Piston ring
243:alternator.
151:Alternators
59:commutators
40:automobiles
1441:Categories
1393:Power band
1353:Oil filter
1327:Thermostat
1272:EGT sensor
1234:MAF sensor
1229:MAP sensor
1214:Air filter
1178:Alternator
1137:Spark plug
1069:Carburetor
995:Rocker arm
935:Valvetrain
866:Crankshaft
810:Automobile
751:, page 993
726:2012-07-24
533:References
440:newspapers
364:Efficiency
333:water pump
275:field coil
192:rectifiers
177:commutator
169:slip rings
67:alternator
32:alternator
1127:Glow plug
1089:Fuel tank
1084:Fuel pump
851:Crankcase
509:Footnotes
470:June 2022
397:does not
234:Operation
220:rectified
212:polyphase
190:A set of
25:V8 engine
1426:Category
1371:Dry sump
1367:Wet sump
1358:Oil pump
1322:Radiator
1239:Throttle
1099:Ignition
970:Camshaft
895:Flywheel
876:Cylinder
861:Crankpin
1398:Redline
1282:Muffler
1183:Battery
1107:Magneto
454:scholar
418:removed
403:sources
349:amperes
155:dynamos
124:magneto
94:Valiant
92:on the
77:History
44:battery
1421:Portal
1209:Airbox
1188:Dynamo
915:Piston
905:Stroke
884:layout
812:series
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554:Allpar
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208:ripple
114:Dynamo
55:dynamo
48:engine
1381:Other
1005:Valve
975:Chest
669:Bosch
571:(PDF)
461:JSTOR
447:books
328:diode
282:delta
173:brush
61:. As
1363:Sump
880:bank
841:Bore
745:ISBN
673:ISBN
521:See
433:news
401:any
399:cite
286:star
216:belt
210:, a
167:Use
100:and
98:Ford
1348:Oil
937:and
822:and
761:809
412:by
290:wye
284:or
222:to
202:to
30:An
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