# How commutators reverse the direction of current? [closed]

I've seen this video and read this article about commutators but I still couldn't get how commutators reverse the direction of current.I would like an simple and intuitive answer.

• What about e.g the Wikipedia article is unclear to you? May 3, 2016 at 8:22
• @Nephente:I only could get that the conductor is rotating but I couldn't get how the rotation reverses the current direction since the positive and negative terminals doesn't change at the carbon brushes. May 3, 2016 at 8:26
• Commutators are simple mechanical switches that "turn" a circuit element around. If pole A was connected to to $net_A$ and pole B was connected to $net_B$, then the commutator connects A to $n_B$ and B to $n_A$. This can be done synchronously to the rotation of an electrical machine, which turns the AC voltage generated by the coils of that machine into a pulsating DC voltage. May 3, 2016 at 8:29
• @CuriousOne:Oh sorry I couldn't get what you meant by $net{A}$. May 3, 2016 at 8:44
• I thought this was a learning forum. I understand the OP's question very clearly and am wondering why so many of you 'closed' the question as unclear. Seriously. On other forums like Quora, this exact question was answered thoroughly and in clear detail. Please let's try to include every learner here.
– suse
May 12, 2019 at 23:49

Once the coil completes half a turn (just ignore we have a commutator), then the forces on the coil will be opposite. So the coil has a tendency to rotate in the opposite direction. But no need of worry. We have the commutator. Once the coil has done a $180^0$ rotation, the commutator also makes one. Remember that the current through the coil is dependent on the copper piece contact with the carbon. Here the right copper plate appears on the left side which means the part of coil which was initially right (carrying a current downwards) now appears at the left. The copper plate conduct current from the left. So the current in the coil becomes opposite. Thus the forces again reverse which makes the coil to continue it's rotation along a single direction.