Before revision: 20: Commutation and the Commutator, p. 285-287 Further compensation for self-induction 400px|Brush advance for Self-Induction .Hawkins Electrical Guide, Theo.
After revision: 20: Commutation and the Commutator, p. 285-287 Further compensation for self-induction 400px|Brush advance for self-induction .Hawkins Electrical Guide, Theo.