3D DC Dynamo
The same rotating coil and the same magnet as the AC machine, with one part changed: a split-ring commutator replaces the slip rings. Every half turn the two halves of the ring swap brushes, so the output keeps one polarity instead of alternating.
How to use this simulation
- Step the coil round with the angle slider and watch the brushes cross the commutator gap
- Increase the speed slider to run the machine and build up the output trace
- Compare the coil EMF with the terminal output over one complete revolution
- Rotate the 3D view to see the split ring and where its insulating gap sits
What to look for
- The brushes change halves exactly when the induced EMF passes through zero, so nothing is interrupted mid-current
- Every half-cycle that would have been negative is flipped up into a positive hump
- The output never crosses the axis — it touches zero twice per turn and rises again
- The peak height is the same as the AC machine's; only the sign of alternate halves differs
- The flux curve is still a cosine, so the coil itself is doing nothing different
The physics behind it
Generation is unchanged — ε = NBAω sin ωt is induced in the coil exactly as before. What the commutator changes is the connection to the outside. The gap in the split ring is placed so that the brushes cross from one half to the other at the instant the coil EMF passes through zero. The half-cycle that would have been negative is therefore handed to the external circuit reversed, and the terminals deliver a series of positive humps — pulsating DC with mean value 2ε₀/π.