Hot air and stirling engines

No, not now, I chucked a lot it out in despair, but to be fair those early engines either did not work well or so poorly made I was a bit ashamed of them. I try to do much better work now.

I have a small mill and just learning how to drill accurately positioned holes in a cylinder flange. Real engineers will laugh as they would have learnt that very early on, but we have to start somewhere.

Mark, if you want to come out, just send PM, I,m usually home, but may be off wandering the village on my bike.

Here's a wee one with a 3/6" bore, and 1/2" stroke.

Ian S C

It appears that the Stirling Engine Forum has crashed again, is that 3 times or 4, hope it's only tempory.

Ian S C

The Stirling Engine Forum is up and running again.

Ian S C

Edited By Mark Smith 3 on 18/03/2017 01:14:10

Hi mark, good to see you back making. Go to top green line on the page, 4th from left click on albums/camera, follow instructions, reduce photos to a suitable size, some of mine are 800 x 600, but most are 640 x 480.

Ian S C

I'll be watching, see what you have been up to in your new workshop. have you still got the old Barns lathe?

Ian S C

Did the old lathe die in the earth quake, or did you just flog it off, it was a pretty depressing time, we just don't know how lucky we are out here on the plains.

The wee motor above was my last Stirling Engine completed, there is a Rhombic part built on the shelf while I fiddle around with a single cylinder open crank 4 stroke IC motor.

Ian S C

Hi Guys, Those hub dynamos, and indeed most bicycle dynamos, are designed to not need a regulator. The way they do this is by sizing the winding to produce a maximum current that is equal to what is required by the load. If you run one open circuit, the voltage produced will be proportional to the rpm, and at higher speeds can get quite high. When the correct load is connected, the current taken by the load keeps the voltage reasonably within limits. Effectively the load is being supplied with a constant current, once the speed is high enough to work properly. One difficulty with this scheme is that the resistance of the filaments increases as they get hotter, so the voltage does tend to rise with rpm.

One thing this leads to on bikes is a tendency to blow both bulbs at once...if the headlight goes,or comes loose, all the current will go through the tail lamp, which will not survive.

If you want better regulation, the simplest way is to rectify the AC and connect a suitable battery. A bike dynamo is usually rated for about 0.5 Amps if I recall correctly. so a motorcycle size of battery can probably absorb that sort of charge rate without needing any other regulator.

John

Hi John, I'v got an old Sturmy Archer hub dyno, I rigged it up to use on a wind turbine(live in Canterbury, nor west winds), I only got two types of wind, too much, and too little. I have run it from my Ross Yoke ALPHA motor.

As for regulation, I just load things up until the voltage stays stable at the rate that I want. But I'm going to go electronic and use a LM317K voltage regulator so that I can have an adjustable voltage supply. For most work I need a 12V supply for the fan on the radiator, and 6V for the radio.

Here is an alternator I built from an old 6 pole squirrel cage shaded pole motor that I replaced the armature with a permanent magnet one.

Ian S C