DC Motors

Function of H-Bridge in DC motor control is

• Change the speed of the DC motor

• Change the direction of the DC motor

• Send feedback of the speed of the DC motor

• Measures the speed of the DC motor

Tags

NGSS.HS-PS3-3

to make the Motor A rotate backward and Motor B stop

• Pin 9 - GND, Pin 8 - 5V, Pin 7 - GND

  Pin 5 - GND, Pin 4 - GND, Pin 3 - GND

• Pin 9 - 5V, Pin 8 - GND, Pin 7 - 5V

  Pin 5 - GND, Pin 4 - GND, Pin 3 - GND

• Pin 9 - 5V, Pin 8 - 5V, Pin 7 - GND

  Pin 5 - 5V, Pin 4 - GND, Pin 3 - GND

• Pin 9 - GND, Pin 8 - 5V, Pin 7 - 5V

  Pin 5 - GND, Pin 4 - GND, Pin 3 - GND

Tags

NGSS.HS-PS3-3

Speed change of DC motor is controlled by

• Enable pin

• Input pins

• H-bridge

• Output pins

Why does a DC motor need to be turned on using a starter?

• To protect the motor from damage caused by high starting currents.

• To prevent the risk of electrocution from high starting currents.

• To prevent the risk of electrocution from high starting voltages.

• To increase the input voltage to a high enough level to turn on the motor.

To reverse the direction of current in a motor, current is conducted

• through the armature.

• in the direction of rotation.

• through the brushes to the commutator.

• through the commutator to the armature.

What is the principle behind the operation of an electric motor?

• Electromagnetic Induction

• Coulomb's Law

• Faraday's Law of Induction

• Lorentz Force

Tags

NGSS.HS-PS2-5

NGSS.HS-PS3-5

Why is there a high current when a DC motor is first turned on?

• The resistance is very low on startup.

• When the motor is turned on there is no back EMF.

• When the motor is turned on the back EMF is very small.

• The resistance is zero on startup.

How does the DC starter reduce the current on startup?

• There is a large resistance permanently in the circuit.

• There is resistance in the circuit that can be decreased in stages.

• There is an inductor in the circuit.

• There is a capacitor in the circuit.

How does the overload release protect the motor from power surges?

• Its magnetism increases and it attracts a lever which causes a short circuit and demagnetises the no volt coil.

• Its magnetism increases and it attracts a lever which causes a short circuit and magnetises the no volt coil.

• Its magnetism decreases and it attracts a lever which causes a short circuit and magnetises the no volt coil.

• Its magnetism decreases and it attracts a lever which causes a short circuit and demagnetises the no volt coil.

Tags

NGSS.HS-PS2-5

NGSS.HS-PS3-5

The speed of a DC series wound motor can be varied by..

• a variable resistor placed in series with the armature

• a variable resistor placed in series with the field coil

• a variable resistor placed in parallel with the armature

• a variable resistor placed in parallel with the field coil