1. Positive (+) brush holder
2. Negative (-) brush holder
3. Positive (+) brush holder
4. Negative (-) brush holder
2. Insert the brush into the holder and move the brush to the commutator, then hook the spring on the spring balance. Measure the spring tension at the moment when the spring lifts the brush.
2. spring; 3. brush
Spring tension: 15.7-17.7 N
