DCMotors_m

According to the sources, which of the following is NOT listed as a main attraction of DC motor drives?

• Simple but precise control
• High starting torque
• Low maintenance requirement
• Smooth rotation down to zero speed

The generic composition of a DC drive system includes a DC Motor, Electronic Converter, Input Power Source, Load, and which other key component according to the diagram?

• Transformer
• Control unit
• Filter circuit
• Braking resistor

DC drives are categorized into two types based on their operating quadrants. What are these two types?

• Single-quadrant and Dual-quadrant drives
• Forward-only and Bidirectional drives
• 2-quadrant and 4-quadrant drives
• Accelerating and Decelerating drives

Compared to Thyristor drives, IGBT drives are characterized by:

• Slower speed response and lower switching frequency
• Faster speed response and lower switching frequency
• Slower speed response and higher switching frequency
• Faster speed response and higher switching frequency

In the context of DC motor speed control in drive systems, the motor primarily responds to which characteristic of the input voltage?

• The peak value of the voltage pulses
• The frequency of the voltage pulses
• The mean value of the input voltage
• The ripple content of the input voltage

The Torque/Speed characteristic graph for a DC motor driven by a mean voltage (v_{a mean}) shows a gradient that is constant. How can the axis intercept be altered according to the source?

• By varying the load torque (T_L)
• By varying the magnetic flux (Φ)
• By varying the armature resistance (R_a)
• By varying the mean applied voltage (v_{a mean})

According to the provided example calculation for a separately-excited DC motor, what are the calculated electrical (τ_e) and electromechanical (τ_em) time constants?

• τ_e = 0.02 s, τ_em = 0.076 s
• τ_e = 0.5 s, τ_em = 1.15 s
• τ_e = 10 ms, τ_em = 0.2 s
• τ_e = 0.076 s, τ_em = 0.02 s

In the direct current-limit structure of a DC drive system, what is the primary function of the current limiter?

• To regulate the motor speed
• To prevent the armature voltage from exceeding a set limit
• To ensure the armature current does not exceed a set threshold value
• To generate the switching signals for the power electronic converter

Which DC drive system structure possesses inherent short circuit protection and fast speed response?

• Direct current-limit structure
• Inner current-loop structure
• Speed loop only structure
• Open-loop control structure

In a 2-quadrant IGBT based power circuit, the mean armature voltage (v_{a mean}) is described as being only positive. What is stated about the mean armature current (i_{a mean})?

• It must also be positive only
• It must be negative only
• It can be positive, negative, or zero
• It can only be zero