In phase control and Integral cycle control the supply voltage is ac and the armature voltage is rectified ac, where as in chopper control the supply is dc and the average armature voltage is proportional to the duty ratio of the chopper. The chopper system is used for dc traction & battery operated vehicle - Choppers using thyristors are more complicated than the phase control system. This is because an auxiliary commutation arrangement is necessary for choppers, whereas commutation is natural owing to a.c. supply in phase control or integral cycle control. Read the paragraph carefully and answer the question based on it.
In a single quadrant chopper how can the direction of dc motor be reversed
by changing the field
The question is about changing the direction of a DC motor in a single quadrant chopper. The correct answer is to change the field, which affects the direction of rotation of the motor.
A single quadrant chopper is a type of DC-DC converter that only allows operation in one of the four quadrants of the speed-torque space. Typically, it facilitates motoring operation, where the motor rotates in a single direction and operates as a load.
- Changing the Field: The direction of a DC motor can be reversed by changing the direction of either the armature current or the field current. In practical applications, it is more common to change the field current direction since it requires less power and minimizes sparking in the armature.
- Explanation of Incorrect Options:
- By changing the direction of the freewheeling diode: This does not affect the motor's direction. A freewheeling diode allows the current to continue flowing through the inductive load when the switch is turned off, helping to prevent voltage spikes.
- By changing the chopper frequency: The frequency of the chopper influences the switching characteristics and efficiency but does not change the direction of motor rotation.
- By applying a filter: Filters are used to smooth out voltage or current ripples but do not affect the motor's direction.
- Conclusion: To reverse the direction of a DC motor in a system using a single quadrant chopper, the field current direction should be changed.
Therefore, the most appropriate way to reverse the direction of a DC motor in a single quadrant chopper is by changing the field.
Similar Questions
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Important Questions from Choppers
Which of the following components convert fixed DC to variable DC?
What happens in a buck regulator?
Choppers are _______ converters.
A chopper is a -
If T is the time period for a chopper circuit and α is its duty cycle, then the chopping frequency is
