In direct-current (dc) motor nomenclature, the terms “series” and “parallel (shunt)” refer to which internal connection within the motor?
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Athe connection of the motor and controller
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Bthe connection of the field coil and armature windings
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Cthe connection of the brush and commutator
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Dthe connection of the motor batteries
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Ethe shaft coupling configuration
Answer
Correct Answer: the connection of the field coil and armature windings
Explanation
Introduction / Context:DC motors are classified by how their field windings are connected relative to the armature: series, shunt (parallel), and compound. These configurations strongly affect torque–speed behavior, starting current, and regulation, which is why correct terminology matters in troubleshooting and selection.
Given Data / Assumptions:
- We are distinguishing common dc motor types by internal wiring.
- Armature is the rotating winding; field coil(s) create the magnetic field.
- External controllers, batteries, and mechanical couplings are not the focus of “series” and “shunt.”
Concept / Approach:In a series dc motor, the field winding is connected in series with the armature, so the same current flows through both. This yields high starting torque but poor speed regulation. In a shunt (parallel) dc motor, the field winding is connected in parallel with the armature across the supply, producing more constant speed. Compound motors combine both windings to balance torque and regulation.
Step-by-Step Solution:Identify the internal elements: field coil(s) and armature.Series motor: I_field = I_armature (same series current).Shunt motor: V_field = V_armature (both across supply).Therefore, “series” vs “parallel” refers to field–armature connection.
Verification / Alternative check:Torque–speed curves confirm behavior: series motors accelerate aggressively under reduced load; shunt motors maintain speed more tightly. Wiring diagrams corroborate the field–armature connection difference.
Why Other Options Are Wrong:Motor–controller wiring, battery connections, and shaft couplings are external concerns and do not define series vs shunt motor types.
Brush–commutator connections are intrinsic to all brushed dc motors and do not differentiate configurations.
Common Pitfalls:Assuming a series motor is universally better due to high torque; its poor speed regulation can be dangerous without proper load.
Final Answer:the connection of the field coil and armature windings