Muller Dynamo

[gyulasun]

Hi Gyula


Which DC-DC converter would you choose to be good for looping BEMF output to source:
http://www.ebay.com/itm/DC-DC-Converter-Regulator-Step-up-Step-down-2-1-/370538642812?pt=LH_DefaultDomain_0&hash=item5645d2fd7c#ht_1990wt_914


or this one:
http://www.ebay.com/itm/DC-Converter-Isolated-Power-Supply-In18V-75V-Out-12V-6W-/350287013003?pt=LH_DefaultDomain_0&hash=item518ebba48b#ht_953wt_1396


JoeFR

Hi Joe,

Both could be a good choice...   if you need only a fixed 12V output at 0.5A max, then the second one is ok,, here is its data sheet:
http://www.szfore-sight.com/pic/p/20107920417271.pdf 
so it has a 81% efficiency and 17mA idle current. This idle current is not known for the first converter, also it does not turn out if it is isolated or not.  Probably not because otherwise it would mentioned.  But this first one has a wide input range and adjustable output voltage range, with 2A current load possibility, claimed efficiency also sounds good. The missing idle current data and if it is isolated or not could be asked from the seller or from the Asia Engineer on ebay.

The Maplin choice Deepcut has just mentioned has a 3A current load possibity, with step-switchable output voltages, though it needs higher than 12V input to get the max allowable 12V output. Its input voltage range may extend to 15-16V only, designed for cars. I have not noticed efficiency claims for this, I assume at least over 80%...

Gyula

[gyulasun]

Hi Gyula,

Thanks for the reply, I'd rather not use that ciruit, co'z im generating more heat and more input power, poor efficiency...

can you suggest a dc to dc converter ciruit that maybe a much better design to bulid? from where i live it's hard to find a ready made high efficiency converter...

cc

If you mean you would build one from components then the first thing to define is the input voltage range and output current needs.  Then comes the component costs and you may end up with similar prices like ebay offers... lol  though postage cost may make the ebay choice more expensive than building from components. 
So I suggest to define your specs and we may find a schematic and the needed components.

Gyula

[highrollerscorp]

so i just need to hook up two meters in series then short one to amps and let the other meter read the volts?

[DeepCut]

I have trouble with it sometimes and i'm not sure why.

But you're meant to measure the amps in series with a load on the gen coils, the load can just be a resistor, and the voltage in parallel with the load.

I just tried it just now to video it for ya but i can't measure the current

[joefr]

Hi all


Here is my new video after long time where I am testing the No Hall Pulse Motor Mosfet driver and BEMF CAP Charge and Discharge to load ( light bulb ) circuit Arduino controlled.
I am using the principle which Kone is saying is good to capture and use BEMF from drive coils:
Charge CAP from BEMF -> Disconnect CAP from drive coil -> Dump stored energy from CAP to load -> Disconnect CAP from load and repeat the cycle.
In my test the motor RPM drops a little but I have to find a sweet spot and the right CAP size to speed up the rotor while using the BEMF.


OK here is the video:
http://www.youtube.com/watch?v=a75Gf7yrCCA


JoeFR