raviram87

i have often seen bicycles having their own lights in the front... these lights come from a dynamo usually present at the back wheel...

how exactly does the system work? is the system producing AC voltage?

Nigel Goodwin

It could be either, it depends on the design - but there's no need to have DC to feed a lamp.

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Dynamos can produce AC or DC depending if they have a commutator. If they have a commutator then you get DC out. If they don't then they are a simple alternator.

Alternators produce AC which is often rectified by internal diodes to DC

Modern alternators also have the advantage that they produce 3 phase AC so when recitified to DC they have less ripple than rectified single phase AC.

mvs sarma

Hai Raviram,
Cycle dynamo as conventionally used term. most of the manual by-cycles "Dynamos" are really alternators with permanent magnet working as exciter and rotary output taken through slip rings. Now imagine the alternator with one terminal of the output connected to cycle metal body. the second terminal is brought to the front thro' a wire and connected to the Head light thro an ON/OFF or LOW or High beam switch. then another parallel wire is run from the alternator to a rear tail lamp (red one), and in this case also the return is again the cycle body.

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Hero999

Bicycle alternators don't nromally have slip rings, the magnet is spun and the coil is stationary.

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mvs sarma

Right, Stand corrected. I recollect my very old memories as I once only saw few decades back. Thanks Hero999

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