392:; hoist drives on such cranes typically use rheostatic braking. Reversing drives with (intentional) plug braking typically use rheostatic control for acceleration, and always have resistance in the motor circuit, when plug breaking is applied, to limit the reverse (braking) torque. Plugging is usually achieved by moving the controller, briefly, to the first step of the opposite direction, and then back to the off position. After zero speed is reached, plugging must cease to avoid the drive running in reverse, and this function may be provided automatically, by a 'plugging relay'. Plugging does not fit well with inverter-controlled drives; it is becoming less common, and it is actively discouraged in modern crane operation.
236:
magnetic field rotate against each other, determined by the rotation of the wheels and the ratio of power shaft to wheel rotation. The amount of braking power is controlled by varying the strength of the magnetic field through the amount of current in the field coils. As the rate of electrical power generation, and conversely braking power, are proportional to the rate at which the power shaft is spinning, a stronger magnetic field is required to maintain braking power as speed decreases and there is a lower limit at which dynamic braking can be effective depending on the current available for application to the field coils.
337:
36:
126:
324:(HEP) loads, braking energy can be used to power the train's on board systems via regenerative braking if the electrification system is not receptive or even if the track is not electrified to begin with. The HEP load on modern passenger trains is so great that some new electric locomotives such as the
408:
to perform a self-load test of the power output of a locomotive. With the locomotive stationary, the main generator (MG) output is connected to the grids instead of the traction motors. The grids are normally large enough to absorb the full engine power output, which is calculated from MG voltage and
242:
For permanent magnet motors, dynamic braking is easily achieved by shorting the motor terminals, thus bringing the motor to a fast abrupt stop. This method, however, dissipates all the energy as heat in the motor itself, and so cannot be used in anything other than low-power intermittent applications
285:
is employed whereby the current produced during braking is fed back into the power supply system for use by other traction units, instead of being wasted as heat. It is normal practice to incorporate both regenerative and rheostatic braking in electrified systems. If the power supply system is not
235:
The amount of resistance applied to the rotating shaft (braking power) equals the rate of electrical power generation plus some efficiency loss. That is in turn proportional to the strength of the magnetic field, controlled by the current in the field coils, and the rate at which the armature and
223:
windings with a (relatively) moving external magnetic field, with the armature connected to an electrical circuit with either a power supply (motor) or power receptor (generator). Since the role of the electrical/mechanical energy converting device is determined by which interface (mechanical or
387:
A third method of electric braking is plug braking or 'plugging', under which a reverse torque is applied for a short time. It is the most rapid form of electric braking, but comes at the disadvantage of applying significant transient stresses to motors and mechanical components. It is typically
374:
Although blended braking combines both dynamic and air braking, the resulting braking force is designed to be the same as the air brakes on their own provide. This is achieved by maximizing the dynamic brake portion, and automatically regulating the air brake portion, because the main purpose of
388:
abrupt and 'jerky', the braking equivalent of a 'jog' in forward motion, and plug braking is never applied in electric traction applications. Nonetheless, it has been applied widely to applications such as long-travel and cross-travel drives of direct current and alternating-current powered
224:
electrical) provides or receives energy, the same device can fulfill the role of either a motor or a generator. In dynamic braking, the traction motor is switched into the role of a generator by switching from a supply circuit to a receptor circuit while applying electric current to the
358:
Dynamic braking alone is not enough to stop a locomotive, because its braking effect rapidly diminishes below about 10 to 12 miles per hour (16 to 19 km/h). Therefore, it is always used in conjunction with another form of braking, such as an
259:. Large cooling fans are necessary to protect the resistors from damage. Modern systems have thermal monitoring, so that if the temperature of the bank becomes excessive it will be switched off, and the braking will revert to being by
494:
218:
of a rotating shaft (electric motor) is the inverse of converting the mechanical energy of a rotating shaft to electrical energy (electric generator). Both are accomplished through the interactions of
627:
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Yard locomotives with onboard energy storage systems which allow the recovery of some of the energy which would otherwise be wasted as heat are now available. The
440:, and the heat is dissipated (via a heat exchanger) by the engine cooling radiator. The engine will be idling (and producing little heat) during braking, so the
375:
dynamic braking is to reduce the amount of air braking required. That conserves air and minimizes the risks of over-heated wheels. One locomotive manufacturer,
484:
615:
239:
The two main methods of managing the electricity generated during dynamic braking are rheostatic braking and regenerative braking, as described below.
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5348 diesel-electric locomotive employs dynamic braking. The cooling grill for the brake grid resistors is at the top center of the locomotive.
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290:, i.e. incapable of absorbing the current, the system will default to rheostatic mode in order to provide the braking effect.
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379:(EMD), estimates that dynamic braking provides between 50% and 70% of the braking force during blended braking.
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174:-based braking components, and regeneration lowers net energy consumption. Dynamic braking may also be used on
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due to cooling limitations, such as in cordless power tools. It is not suitable for traction applications.
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batteries have also been used to store energy for use in bringing trains to a complete halt.
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with hydraulic transmission may be equipped for hydrodynamic braking. In this case, the
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The electrical energy produced by the motors is dissipated as heat by a bank of onboard
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485:"Wayside and on-board storage can capture more regenerated energy"
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Use of the traction motors as generators when slowing a vehicle.
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325:
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363:. The use of both braking systems at the same time is called
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in 2006, which has been fitted with dynamic blended braking
187:
483:
Professor Satoru Sone, Kogakuin
University (2007-07-02).
838:
Electro-pneumatic brake system on
British railway trains
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were designed without the traditional resistance grids.
566:"What is the impact of crane plugging? | Konecranes"
400:It is possible to use the brake grids as a form of
592:"Six dangerous misconceptions about crane safety"
316:On modern passenger locomotives equipped with AC
929:
659:
625:Regenerative braking boosts green credentials
62:introducing citations to additional sources
833:Electronically controlled pneumatic brakes
828:Diesel electric locomotive dynamic braking
666:
652:
541:"Overhead crane terminology | Konecranes"
205:
589:
335:
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52:Relevant discussion may be found on the
517:"What is plugging for electric motors?"
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14:
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802:Westinghouse Brake and Signal Company
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297:model, for example, is being used by
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29:
24:
673:
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228:that generate the magnetic field (
147:when slowing a vehicle such as an
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497:from the original on 10 July 2018
459:Retarder (mechanical engineering)
395:
590:Dunville, Larry (10 July 2003).
45:relies largely or entirely on a
34:
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320:pulling trains with sufficient
914:Railroad Safety Appliance Act
797:Westinghouse Air Brake Company
583:
558:
533:
509:
13:
1:
637:Railway Gazette International
490:Railway Gazette International
469:
307:Kansas City Southern Railway
7:
447:
436:. Braking energy heats the
200:hybrid electric automobiles
10:
959:
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139:is the use of an electric
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810:
774:
681:
521:www.motioncontroltips.com
390:overhead traveling cranes
299:Canadian Pacific Railway
843:Emergency brake (train)
689:Counter-pressure brake
454:Counter-pressure brake
355:
311:Union Pacific Railroad
206:Principle of operation
133:
709:Electromagnetic brake
432:in the same way as a
377:Electro-Motive Diesel
339:
255:, referred to as the
128:
413:Hydrodynamic braking
342:Connex South Eastern
283:regenerative braking
267:Regenerative braking
58:improve this article
823:Diesel brake tender
444:is not overloaded.
352:Blackfriars station
279:electrified systems
184:light rail vehicles
904:Pearson's Coupling
791:New York Air Brake
782:Faiveley Transport
751:Regenerative brake
744:Railway disc brake
704:Eddy current brake
694:Countersteam brake
630:2007-10-15 at the
618:2016-03-04 at the
570:www.konecranes.com
545:www.konecranes.com
464:Eddy current brake
418:Diesel locomotives
356:
273:Regenerative brake
247:Rheostatic braking
134:
925:
924:
884:Dead man's switch
734:Railway air brake
729:Kunze-Knorr brake
216:mechanical energy
212:electrical energy
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73:"Dynamic braking"
16:(Redirected from
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409:current output.
158:. It is termed "
130:Norfolk Southern
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18:Rheostatic brake
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938:Dynamic braking
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916:(United States)
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899:Hydraulic brake
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853:Dowty retarders
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719:Heberlein brake
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632:Wayback Machine
620:Wayback Machine
613:Blended braking
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438:hydraulic fluid
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365:blended braking
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332:Blended braking
281:the process of
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153:diesel-electric
137:Dynamic braking
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607:External links
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596:The Fabricator
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426:fluid coupling
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396:Self-load test
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322:head-end power
271:Main article:
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188:electric trams
180:multiple units
141:traction motor
121:
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114:September 2023
56:. Please help
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811:Other aspects
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75: –
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69:Find sources:
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49:
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47:single source
43:This article
41:
37:
32:
31:
19:
787:Knorr-Bremse
766:Vacuum brake
698:
635:
595:
585:
574:. Retrieved
572:. 2018-10-02
569:
560:
549:. Retrieved
547:. 2017-12-12
544:
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524:. Retrieved
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499:. Retrieved
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383:Plug braking
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364:
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315:
303:BNSF Railway
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257:braking grid
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192:trolleybuses
168:regenerative
136:
135:
111:
101:
94:
87:
80:
68:
44:
761:Track brake
756:Steam brake
434:water brake
402:dynamometer
288:"receptive"
226:field coils
210:Converting
932:Categories
909:Pneumatics
889:Drum brake
739:Disc brake
724:Hand brake
576:2024-02-10
551:2024-02-10
526:2024-02-10
470:References
428:acts as a
350:at London
295:Green Goat
230:excitation
160:rheostatic
156:locomotive
84:newspapers
869:Air brake
818:Brake van
640:July 2007
501:29 August
406:load bank
361:air brake
345:Class 466
318:inverters
253:resistors
164:resistors
145:generator
54:talk page
848:Retarder
628:Archived
616:Archived
495:Archived
448:See also
442:radiator
430:retarder
261:friction
221:armature
196:electric
176:railcars
172:friction
149:electric
214:to the
166:, and "
98:scholar
369:Li-ion
326:ALP-46
263:only.
194:, and
100:
93:
86:
79:
71:
879:Brake
682:Types
178:with
143:as a
105:JSTOR
91:books
503:2021
309:and
198:and
77:news
424:or
404:or
348:EMU
277:In
232:).
151:or
60:by
934::
634:,
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568:.
543:.
519:.
493:.
487:.
367:.
340:A
313:.
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202:.
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789:(
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529:.
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116:)
112:(
102:·
95:·
88:·
81:·
64:.
50:.
20:)
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