(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

I want to know the affect of stator design on bicycle dynamo performance using magnetic circuits, and power output. The bicycle dynamo is a single phase AC generator with permanent magnets on its rotor (mounted on hubshell) and a lundell type armature(mounted on bike axle). At 30rpm, the dynamo is expected give out 2.4W at 3V. Load is 15ohm.

2. Relevant equations

I've tried using Faraday' law, Voltage generated=-N(change in flux & area)over time, but I keep getting larger results than expected.

My attempt at applying:

Faraday's Law:

Total B of the magnet is: 4000mT, so for this voltage estimation I am assuming perfect coupling of field through the stators

The coil has a cross area of 483.05mm^2 and 320 turns.

There are 28 poles, so I assume the coil experiences a field change 14 times per second at 30rpm.

So Voltage generated = -(320)(4000mT)(483.05mm^2*14) = 8.65V

How do you factor in the 15 ohm load into the basic equation?

3. The attempt at a solution

Aside from the attempt in the previous section, I'm stuck. Would appreciate links or recommendations of reference if some reading is in order.

Thank you,

Derek

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Designing a lundell(clawpole ) Type Generator

**Physics Forums | Science Articles, Homework Help, Discussion**