Dynamo brain storm or bust?

[Metal Butcher]

In my previous thread about building Elmer's #44 member mklotz was kind enough to post inspirational pics of his build of the #44. The neat looking dynamo he added to its mounting base adds a good amount of visual interest that could be used with most of the models we build.

Unfortunately the cost of said dynamo is slightly prohibitive for me and possibly others on a tight budget.

An idea struck! The dynamo looks very similar to the small low volt can type hobby motors I bought about 30 years ago, and still available today for a dollar or two. A small box of them is still in my collection of "you name it" odds and ends.

Is there anyway to convert thees (I'm electrically challenged) to work like a dynamo?

Machining up a housing with base to hide the can motor would be relatively easy.

It may not be a viable idea, but I had to ask.

-MB

 

[black85vette]

A permanent magnet DC motor will generate electricity when the rotor is spun. Some electric car designs exploited this by using the motor to slow down the car and use the energy to return some charge to the battery.

 

[Bluechip]

MB

If they are permanent magnet motors, they'll generate anyway.

Not a lot, but more than enough to operate a LED or a low watt filament lamp. Maybe 3V 50mA or so.
Depends on the motor.
You can use the small stepper motors salvaged from printers etc. the same. Just need to wire the two windings in series and connect via a small bridge rectifier. Assuming it's not a defective stepper ...

Or as Black85vette said while I was typing ... ;D

Dave BC

 

[John Rudd]

Depending on the size of the motor and certain electrical characteristics you may need to spin it fairly fast to generate anything useful.....

In the RC modelling world we use brushless motors because they are much more efficient compared to a brushed motor. You could use one of them but you will need to rectify the output to obtain a dc voltage.

Shout up if you want to pursue this route and I'll help...

 

[mklotz]

Remember those bicycle generators that powered a small headlight? They were popular when I was a kid. They had a knurled wheel that rode on the bike tire and turned the generator shaft. If you can find one at a yard sale or similar, it would be easy to rig up to an engine.

 

[Noitoen]

Modern car's electric fan motor, especially those lager diameter types with 6 or 8 magnets, can generate quite a lot of power at relatively slow speeds < 1000 rpm. Also those Chinese electric scooter motors will generate 24vdc. On permanent magnet motors, the output voltage is proportional to the speed.

 

[mu38&Bg#]

Any permanent magnet DC motor will generate when the shaft is driven. The motor characteristics will determine how fast it needs to turn to output a given voltage and how much torque will be required to supply the current necessary. The motor characteristics will also determine th maximum amount of power it can output without overheating. Brushed motors need no rectifier and can be connected directly to a DC load. Lighting an LED requires the correct voltage and trivial amount of current for low power LEDs. If the voltage is greater than the LED requires, an appropriate resistor will be needed.

 

[putputman]

MB, here is a video of the PM dynamo driving a computer fan & 3 LEDs with a Chuck Fellows design JD air engine. You can notice the fan will drag the engine down. The 3 LEDs have no effect on the engine. I wonder just how many LEDs the generator could light.

Like you, I am electronically challenged, but maybe one of those "spark chasers" could explain it to us.

I think the generator castings were about $45.00 on ebay.



Good luck with your project.

 

[Tin Falcon]

correct me if I am wrong . how about the motor from an old cordless drill driver these should be able to had cheap or free as it is often cheaper to get a whole set rather than a couple of battery packs when the batteries fail to charge. I would think they put out a decent amount of power for what you want.
Tin