The counter EMF of a DC motor is maximum...

Question 1 / 270705eccefa3bacbc34ba4d4805a

Question 1 of 270705eccefa3bacbc34ba4d4805a

The counter EMF of a DC motor is maximum when the __________.

Question 1 of 27070

The counter EMF of a DC motor is maximum when the __________.

🔍 Key Concepts

• counter EMF (back EMF) in a DC motor and what causes it • relationship between armature speed and the amount of counter EMF produced • what happens to current draw from the supply as counter EMF increases

💭 Think About

• Think about when the armature conductors are cutting the most lines of magnetic flux per second. At what speed condition does this occur? • Consider what the counter EMF is doing right when the motor starts, as it speeds up, and when it is running steady. How does that change the net voltage across the armature? • Which of the listed conditions would cause the motor to draw the least current from the source because the counter EMF is opposing most of the applied voltage?

✅ Before You Answer

• Recall that counter EMF is proportional to armature speed in a DC motor (E ∝ Φ × N). • Check which option corresponds to the highest and most stable operating speed, not just ‘moving’ or ‘starting to move’. • Verify in your mind what happens to armature current at start vs. near full speed and relate that to counter EMF magnitude.

Question 1 of 27070

The counter EMF of a DC motor is maximum when the __________.

motor is at rated speed

armature is not turning

motor is almost up to rated speed

armature has just begun to turn