Q1. Which of the following is not true of a DC machine commutator? (a) Its made of copper (b) Its also known as slip rings (c) Its also known as split rings (d) Its mounted on the rotor shaft (e) Its connected to the armature conductors Q2. Which of the following is true of a DC machine commutator? (a) The commutator provides external access to the armature via the brushes (b) The commutator segments are electrically insulated from each other and the rotor (c) The commutator acts as a mechanical rectifier in a DC generator (d) The commutator ensures that the current entering the armature of a DC motor is of the correct polarity (e) All of the above The main reason why Copper is preferred over Aluminum for DC machines windings is because: Q3. (a) Copper is less expensive than Aluminum (b) Copper is a better conductor than Aluminum (c) Copper is lighter than Aluminum (d) Copper has a higher melting point than Aluminum. (e) All of the above.

Q: A separately excited generator has lap-wound armature with 12 slots and 5 turns per coil. It is…

A:

Q: 1. Current flowing through the field coils : a. Magnetizes the pole pieces. b. Makes the generator…

A: MCQs type questions are given. Note: As per Bartleby Portal, I am solving first three MCQs.

Q: 3. A 4-pole, simplex progressive lap wound armature-contains 21 slots and two coils sides per slot.…

A: Given Data: number of pole = 4 slots = 21 two coil sides per slot

Q: Hysteresis loss in a dc machine is on frequency of a) independent, dependent, magnetic reversal b)…

A: The solution is provided in the following section:

Q: Determing the front pitch, back pitch, and average pitch of the armature winding.  12 poles     100…

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Q: Select the DC generator used for arc welding. With an elegant drawing explaining its operation.

A: “Since you have posted a question with multiple sub-parts, we will solve the first three sub-parts…

Q: The armature of a separately-excited DC generator has 0.06 effective resistance. Each brush has an…

A: Given- For separately excited dc generator- Armature resistance = 0.06 ohm Brush resistance= 0.015…

Winding and Constructions

Alternating Current (AC) winding is generally of the 3-phase type due to the inherent advantages of the 3-phase machine. Armature coils must be connected to the yield balance (equivalent in magnitude and 2/3 of the series phase difference of the rod) 3-phase electromotive forces (emf). The armature should be divided into step-bands to start with slots around the perimeter.In the construction of AC machines, the frame is used as an external protective shield to protect it from environmental conditions. The frame also serves as the outer perimeter, allowing the interior to be easily placed. The static state section of the devices is the stator winding attached stator.