Question 1

Dynamic braking for an AC squirrel cage motor can be accomplished by connecting direct current to the stator winding.

Accepted Answer

When DC is applied to the stator winding of an AC squirrel cage motor, it creates a magnetic field that opposes the rotation of the rotor, causing the motor to slow down and eventually come to a stop. This is known as dynamic braking. Connecting direct current to the stator winding causes the motor to act as a generator and produces a magnetic field that opposes the rotation of the rotor, thereby providing dynamic braking.

Question 2

A motor should be stopped by dynamic braking alone.

Accepted Answer

Dynamic braking alone may not be sufficient to stop a motor, especially if the load is heavy or the motor is moving at high speeds. Additional braking methods may be needed to completely stop the motor. Dynamic braking can be used as a method to slow down a motor, but it should not be the sole method of stopping the motor. Other methods such as mechanical brakes or motor coasting should also be used to ensure complete stopping of the motor.

Question 3

Dynamic braking is applied in about one-fifth the time required to set the majority of shunt brakes.

Accepted Answer

Dynamic braking uses the motor itself to slow down the load, so it can be applied much more quickly than setting shunt brakes, which require physically changing the position of brake shoes or pads to apply friction. Dynamic braking involves using the electrical resistance of the motor to generate braking force, which can be applied quickly, whereas setting shunt brakes involves physically engaging brake mechanisms, which takes longer. Therefore, dynamic braking can be applied much more quickly than setting shunt brakes.

Question 4

On high-speed drives, it is recommended that braking be provided to reduce the drive speed to a low value before the brakes are set.&#10;A)smooth&#10;B)dynamic&#10;C)regenerative&#10;D)phase

Accepted Answer

Dynamic braking is recommended on high-speed drives to reduce the drive speed to a low value before the brakes are set. This is because dynamic braking provides a smooth and controlled deceleration, which helps to prevent damage to the drive and its components.

Question 5

Dynamic braking can be started by track-type switches installed in the end zones of overhead traveling cranes.&#10;A)limit&#10;B)toggle&#10;C)pneumatic&#10;D)pressure

Accepted Answer

Dynamic braking is a method of braking where the motor is used as a generator to convert the kinetic energy of the moving crane into electrical energy which is dissipated as heat. The process starts automatically when the track-type limit switches installed in the end zones of the crane detect that the crane has reached the end of its travel. These switches are designed to trigger the dynamic braking system to activate, bringing the crane to a safe stop. Therefore, the best choice for the type of switch used to initiate dynamic braking on overhead traveling cranes is limit switches. Dynamic braking can be initiated by track-type limit switches, which are often installed in the end zones of overhead traveling cranes. These switches are designed to detect when the crane reaches a certain point in its travel and can be used to engage the braking system. Toggle, pneumatic, and pressure switches are not typically used for this purpose.

Question 6

Connecting the armature to a resistance and to the line as well is a process called braking.&#10;A)dynamic&#10;B)smooth&#10;C)regenerative&#10;D)phase

Accepted Answer

Regenerative braking involves using the motor as a generator to convert kinetic energy into electrical energy, which is then fed back into the power grid. This can help to reduce energy consumption and increase efficiency. Neither dynamic, smooth, nor phase braking involve connecting the armature to a resistance and the line simultaneously like regenerative braking does. Connecting the armature to both a resistance and the line is a characteristic of regenerative braking, in which the kinetic energy of the motor is returned to the power supply. Dynamic braking involves only the use of a resistor or eddy current to slow down the motor, while smooth braking refers to a gradual decrease in speed without sudden stops. Phase braking does not involve connecting the armature to a resistance or the line.

Question 7

There are many different methods of providing dynamic braking for small production equipment.

Accepted Answer

There are many different methods of providing dynamic braking for small production equipment, such as using a regenerative braking system, using an eddy current brake, or using a friction brake. There are indeed many different methods of providing dynamic braking for small production equipment, such as using resistors, regenerative drives, or DC injection braking.

Question 8

A synchronous motor can be reconnected as a(n) to provide faster stopping.&#10;A)alternator&#10;B)DC generator&#10;C)regulator&#10;D)accelerator

Accepted Answer

A synchronous motor can be reconnected as an alternator to provide faster stopping by converting the mechanical energy of the motor into electrical energy, which can then be dissipated or fed back into the power system.

Question 9

Stopping a motor by reconnecting it so that it acts as a generator is a method of braking called braking.&#10;A)smooth&#10;B)phase&#10;C)regenerative&#10;D)dynamic

Accepted Answer

The answer of Stopping a motor by reconnecting it so...

Question 10

Dynamic braking is a complex but safe method of emergency or safety braking.

Accepted Answer

The answer of Dynamic braking is a complex but safe...

Deck 50: Dynamic and Regenerative Braking