Hi,
I apologise for the slightly misleading/wrong title, I couldn’t think of a quick and easy way to describe what information I am seeking.
It may be easier if I describe the situation and the experiences that have led to the question.
I have built several engines ((Stirling Alpha and a flame licker (I so hate that name)). They are small and have been built to generate small amounts of electricity, the overall project is for an exhibition on ‘power generation’. I chose to go with a old design of engine and then use this to drive a small dc motor as a generator.
The engines work fine but I soon found that the power output from them is tiny, so tiny that driving a dc motor simply coupled to the fly wheel struggles to keep the engine from stopping.
The electric produced is only to be in the range of around 5V and enough current to power say 10 leds, so I am looking for around 100mA from the set up.
Curiously the flame licker can handle this better than the Stirling engine, I think however this is more to do with the build quality of the engines rather than the design.
So I decided to do away with the motor acting as a generator and move to magnets mounted on the flywheel moving around the outside of several coils. This seems to work better but despite what I originally thought I cant decide which of the following would be better.
Is it better to have the magnets attached to the flywheel and the coil/coils mounted off the engine, or have several coils attached to the flywheel and the magnet mounted off the engine?
Apart from the coupling issue I found that coils moving around a fixed magnet gave better results, however to my thinking I would have thought that it was more efficient to have the magnets on the flywheel and use the extra weight/inertia to help the fly wheel.
I have played with both designs and experimented, time is now short for the final build and I need to decide which to go with. So from a mathematical perspective which should give better performance? I had originally thought that they would both perform the same but this isn’t the case, they do however work better than coupling a dc motor to the flywheel.
I am assuming that in making a alternator style generator (if that is correct?) then a slightly offset magnet on the flywheel that passes by a ring a small coils (8 coils) is the better option, can anyone help me work this out please? Yes I know I don’t come here much but where I normally go no one has any experience of these types of engines!
They have been great to build from scratch though.
I apologise for the slightly misleading/wrong title, I couldn’t think of a quick and easy way to describe what information I am seeking.
It may be easier if I describe the situation and the experiences that have led to the question.
I have built several engines ((Stirling Alpha and a flame licker (I so hate that name)). They are small and have been built to generate small amounts of electricity, the overall project is for an exhibition on ‘power generation’. I chose to go with a old design of engine and then use this to drive a small dc motor as a generator.
The engines work fine but I soon found that the power output from them is tiny, so tiny that driving a dc motor simply coupled to the fly wheel struggles to keep the engine from stopping.
The electric produced is only to be in the range of around 5V and enough current to power say 10 leds, so I am looking for around 100mA from the set up.
Curiously the flame licker can handle this better than the Stirling engine, I think however this is more to do with the build quality of the engines rather than the design.
So I decided to do away with the motor acting as a generator and move to magnets mounted on the flywheel moving around the outside of several coils. This seems to work better but despite what I originally thought I cant decide which of the following would be better.
Is it better to have the magnets attached to the flywheel and the coil/coils mounted off the engine, or have several coils attached to the flywheel and the magnet mounted off the engine?
Apart from the coupling issue I found that coils moving around a fixed magnet gave better results, however to my thinking I would have thought that it was more efficient to have the magnets on the flywheel and use the extra weight/inertia to help the fly wheel.
I have played with both designs and experimented, time is now short for the final build and I need to decide which to go with. So from a mathematical perspective which should give better performance? I had originally thought that they would both perform the same but this isn’t the case, they do however work better than coupling a dc motor to the flywheel.
I am assuming that in making a alternator style generator (if that is correct?) then a slightly offset magnet on the flywheel that passes by a ring a small coils (8 coils) is the better option, can anyone help me work this out please? Yes I know I don’t come here much but where I normally go no one has any experience of these types of engines!
They have been great to build from scratch though.