To achieve spark less commutation brushes of a DC generator are placed ________(a) just ahead of magnetic neutral axis(b) in magnetic neutral axis(c) just behind the magnetic neutral axis(d) can be placed anywhereThis question was addressed to me in an interview for internship.My question is from Commutation Process topic in section Commutation Process & Excitation Methods of DC Machines

To achieve spark less commutation brushes of a DC generator are placed

1.	To achieve spark less commutation brushes of a DC generator are placed ________(a) just ahead of magnetic neutral axis(b) in magnetic neutral axis(c) just behind the magnetic neutral axis(d) can be placed anywhereThis question was addressed to me in an interview for internship.My question is from Commutation Process topic in section Commutation Process & Excitation Methods of DC Machines
Answer» The correct ANSWER is (a) just AHEAD of magnetic neutral axis Best explanation: Brushes collect the current due to the induced emf in the armature COILS. When a brush is at any particular commutator segment, it shorts out that particular coil and DRAWS current from the REST of the coils and fed to the commutator. To achieve all positive outcomes, we place them just ahead of MNS.

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