🔍 Key Concepts

• DC motor reversing – what happens if you reverse current in only the armature, only the field, or both? • In a series-wound DC motor, armature and field are in series and normally see the same current direction. • Look at the schematic: which contacts (labeled O and C) actually swap the connections to the motor terminals when you press OPEN vs CLOSE?

💭 Think About

• When you want a DC motor to reverse, do you need to change the direction of the magnetic field, the armature current, or the relationship between the two? • If the contactors simply interchange the two supply leads going to the armature but leave the field connected the same way, what does that do to the rotation? • If both the field and armature polarities are reversed together, does the direction of rotation change or stay the same?

✅ Before You Answer

• Trace the circuit from the supply to the door motor terminals in the OPEN condition and then in the CLOSE condition – which pair of leads are swapped? • Identify whether the field winding is being reversed, the armature is being reversed, or both together. • Remember: reversing both field and armature together does NOT change rotation; only changing ONE relative to the other does.