| As the brushes ride on the commutator of a DC generator, eventually mica ridges will form between the bars causing sparking and chipping of the brushes. When this happens the mica must be undercut. To what depth is the mica undercut? |
| A) The mica slots are undercut to a depth 1mm below the surface of the commutator bars. |
| B) The mica slots are undercut to a depth approximately twice the width of the slot. |
| C) The mica slots are undercut to a depth approximately equal to the width of the slot. |
| D) The mica slots are undercut. but the actual depth is unimportant. |
