Read the summary and the most important questions on Tweaking a Driveline. Optimizing Electric Motors

• 1 The working principles and characteristics of the following electric motors:

• 1.1 Brushed DC Motor

  This is a preview. There are 3 more flashcards available for chapter 1.1
  Show more cards here

• Name a big advantage for Brushed DC Motors:

  They have a high torque for low speeds and they can easily be controlled

• Describe roughly how this type of Motor works (consider permanent magnets in the stator).

  The rotor consist of several coils connected to power true bridges. One or more coils are activated and starts an magnetic field, this magnetic field is trying to align with the magnetic fields of the stator, to reduce the magnetic reluctance. As soon as the magnetic fields are almost in line the commutator energizes the next winding.

• What is "Magnetic Reluctance"

  Is a measure for the resistance of magnetic flux in an magnetic system.

• What way's are there to control and change the motorspeed?

  Change the clamp voltage
  Use a series resistor
  Use duty cycle

• What is the biggest disadvantage of controlling the motor(speed) by a resistor?

  The heat dissipation

• What big advantage does the resistorcontrolling method bring with it?

  The stall current will decrease

• What advantage does the Duty-cycle control method bring? And why?

  The no-load speed will decrease. Because the motor runs less fast to overcome the lower clamp voltage.

• 1.2 Brushless DC Motor

  This is a preview. There are 1 more flashcards available for chapter 1.2
  Show more cards here

• What can be said about the magnetic fields when the BLDC motor is in Torque mode? And what is the relationship between torque and the magnetic field?

  The magnetics fields are almost in line. The more Torque we need the bigger the angle-shift will between the magnetic fields.

• At what angle shift can we get the highest torque?

  At 90 degrees

• How is the Angle-shift determined?

  It is determent by making use of Hall-Sensors in order to measure the position of the rotor.