How many degrees does one complete revolution of an armature correspond to in a four pole generator?

• A. 360 degrees mechanical, 720 degrees electrical
• B. 360 degrees electrical, 720 degrees mechanical
• C. 180 degrees mechanical, 360 degrees electrical
• D. 720 degrees mechanical, 360 degrees electrical

Answer: (A)

In a four-pole generator, the relationship between mechanical rotation and electrical output is fundamentally linked to the number of poles in the machine. One complete revolution of the armature corresponds to a mechanical rotation of 360 degrees. However, because the generator has four poles, each complete mechanical revolution results in two complete electrical cycles. This is because each pole produces a voltage in the armature as it passes, and with four poles, the armature creates two alternating cycles during that same rotation.

Therefore, when the armature has turned through 360 degrees mechanically, it has effectively produced electrical output for 720 degrees. In electrical terms, this corresponds to two complete cycles (each cycle being 360 degrees), providing a total of 720 degrees electrical output. This relationship highlights the concept of how mechanical rotations correlate with electrical cycles in generators, especially when you consider the number of poles involved.

Thus, the correct relationship is that one complete mechanical revolution of the armature corresponds to 360 degrees mechanically and 720 degrees electrically in a four-pole generator.