25-05-2023, 05:16 PM
Sparking at the brushes as the motor operates is normal. It will be worse if the motor is not in optimal condition. Starter motors have mica insulation between the commutator segments, and this is harder than the copper. When a motor is new the top of the mica is level with the top of the copper segments, but in operation the copper normally reduces by wear and spark erosion more than the mica does (mica is not subject to spark erosion). This is only a problem as the wear becomes excessive. If necessary skimming ideally should remove only mica, although in practice a very small amount of copper is normally taken to enable the machinist to see that he has achieved a truly cylindrical shape.
If using 12 volts sparking is unlikely to be very different from when using 6 volts because the motor turns very much faster on 12, causing a greater back emf.
Going back to your question, sparking is normal within limits, and the 12 v operation makes little difference in my experience.
If using 12 volts sparking is unlikely to be very different from when using 6 volts because the motor turns very much faster on 12, causing a greater back emf.
Going back to your question, sparking is normal within limits, and the 12 v operation makes little difference in my experience.