dynamic braking

(redirected from Dynamic brake)

dynamic braking

[dī¦nam·ik ′brāk·iŋ]
(mechanics)
A technique of electric braking in which the retarding force is supplied by the same machine that originally was the driving motor.

Dynamic braking

A technique for braking in which mechanical energy is converted to heat or electrical energy in order to slow or stop motion. An all-mechanical dynamic brake consists of rotating vanes that circulate a viscous fluid in a manner that generates heat. This is one way that the power of the wind is harnessed for space heating. An electric dynamic brake consists of an electric dynamo in which the mechanical energy is converted to electric form, and either converted to heat in a resistor or returned to the supply lines. Typically, electric braking is accomplished with the same machine that serves as the drive motor. Electric dynamic braking is employed in electric vehicles, elevators, and other electrically driven devices that start and stop frequently. See Wind power

The most common type of dynamic braking will be explained for a direct-current (dc) motor. To accomplish braking action, the supply voltage is removed from the armature of the motor but not from the field. The armature is then connected across a resistor. The electromotive force generated by the machine, now acting as a generator driven by the mechanical system, forces current in the reverse direction through the armature. Thus a torque is produced to oppose rotation, and the load decelerates as its energy is dissipated, mostly in the external resistor, but to some extent in core and copper losses of the machine. See Direct-current motor

Electric braking can also be accomplished by causing the energy of the rotating system to be converted in the armature to electrical energy and then returned to the supply lines. This mode of operation, called regenerative braking, occurs when the counterelectromotive force exceeds the supply voltage.

Interchanging two of the lines supplying a three-phase alternating-current (ac) induction motor also produces braking. In this case, called plugging, the direction of the electromagnetic torque on the rotor is reversed to cause deceleration. Both the energy of the system and the energy drawn from the supply lines are expended in copper and core losses in the machine as heat. The power lines must be disconnected when the rotor comes to rest. See Alternating-current generator, Electric power generation, Electric rotating machinery, Induction motor

References in periodicals archive ?
As usual with a BMW there's a massive list of acronyms that include anti-slip control (ASC) dynamic brake control (DBC), cornering brake control (CBC), M Dynamic Mode (MDM) and quite a few more, which we haven't got room to list.
Elsewhere, features on the new range include newly-designed LED rear lights and dynamic brake lights represent the embodiment of cutting-edge elegance.
Boasting BMW's highest level of standard specification, all 5 Series models come with leather seats, air con, radio/CD player and Bluetooth telephone set up while driver safety items include dynamic stability control consisting of automatic stability control, cornering brake control, dynamic brake control and dynamic traction control.
Boasting BMW's highest level of standard specification, all 5 Series models come with leather seats, air con, radio/CD player and Bluetooth telephone set up, while safety includes dynamic stability control consisting of automatic stability control, cornering brake control, dynamic brake control and dynamic traction control.
A three horsepower stainless steel dynamic brake motor enables smooth operation of the cutting wheel, while a new, larger discharge chute simplifies flow and deters product damage.
A 3 HP stainless steel dynamic brake motor enables smooth operation of the cutting wheel.
Familiar systems from other BMW models such as ABS brakes, Dynamic Stability Control, Dynamic Traction Control, Dynamic Brake Control and Cornering Brake Control are all fitted as standard.
Highly-effective stability and traction control systems deliver stacks of grip, while corner and dynamic brake controls with electronic brake force distribution also contribute to maintaining total control over the proceedings, along with some sharply responsive power steering and well-balanced handling.
Driver safety aids include BMW's Dynamic Safety Control (DSC+) which includes ABS braking with automatic differential brake and brake force distribution, automatic stability control, cornering and dynamic brake control, hill start assist plus engine drag torque control.
The dynamic brake prevents the unit from exceeding a predetermined speed, even when coasting downhill, while the static brake, or automatic parking brake, automatically switches on when the unit stops.

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