Tim's Magnet-Piston Engine Design

[tim123]

Here's a rotary version of the same thing, although I think the attraction is reversed due to the change in orientation of the magnets to one another...

The principle is that when the coil is powered, the iron parts of the rotor are repelled by the iron stator strips, while the shorted-coil section is attracted. Again it's a 50% duty engine (2 stroke).

The shorted-coil sections only produce an opposing field when the external magnetic field is changing, so the optimum motor speed will depend on the inductance of the main coil.

The main features:
- single external coil can be a big as you like.
- no brushes & not very difficult to build.
- strong, (but lumpy) power delivery (would need a flywheel). Large common surface-area between rotor & stator, and wide radius gives lots of torque.

Note that Maxwell said the maximum force between 2 ferromagnets is 100 tonnes per square meter. If the rotor surface area is 1m^2 then that's the maximum force it will be producing. It's a lot.

[conradelektro]

Reminds me of Bob Teal and his "magnipulsion motor":

http://www.free-energy.ws/bob-teal.html

http://www.rexresearch.com/teal/teal.htm

Greetings, Conrad

[tim123]

Hi Conrad , yeah, quite similar indeed... Magnapulsion sounds a bit better than MagPis too... 

[tim123]

I wanted to try to give you guys something a bit more solid to work with, so...

Here are the calclulated specs for a buildable, fairly small version of this device (reciprocating version). I'd strongly suggest you do your own calculations before spending time and money trying to build one, as I could have got this wrong...

I read that it should only take maybe 4,000 Amp Turns to saturate any iron in a core of 1m length. The coil below provides almost 40,000 AT/m at 48W input power. So - I have over-specced the coil by a factor of TEN - so it could probably be smaller and still work well. Note input power is inversely proportional to the size of the coil - so bigger coil = less input power.

Core Cylinder Size: 150mm long, 50mm diameter
Central Fixed Core Length: 30mm
Armature Lengths: 30mm
Throw: 30mm
Coil Outside Diameter: 100mm. 1.5mm wire, 1600 turns, 3.53ohms. 13v = 3.7A = 39,000At/m
Almost 6Kg of copper!

Calculated output power at 1000RPM: 2,300 Watts (If you could get it to run at 10,000RPM - it'd make 23Kw.)
Input power 48 Watts at 50% duty: 24 Watts
C.O.P.: 96

Note: You could use permanent magnets for the armature parts. As they're only 50mm x 30mm - not too expensive. (Also, you can add steel to a magnet to make it effectively longer - so a 20mm thick magnet + 10mm steel is as good as a 30mm magnet)

Note 2: This is calculated with the armatures remaining fully within the core at all times. You could increase the throw easily by letting them partly exit the core at the extremes of stroke. This means a bigger crank, more torque...

[tim123]

Attached is a pic of a prototype design - based on the above specs - which I hope includes the best bits of both my & Luc's designs. Note: the shaft is attatched to the magnets, but slides through the central core - on a PTFE sleeve. The shaft needs one more set of sliding bearings at the crank end to hold it in position.

- It's to scale - so 150mm long, 50mm diameter, 30mm cores, magnets & throw
- Uses PMs, and has a magnetic shaft like Luc's
- Has a big coil, with central core - where all the action happens, like mine.

I think this is pretty easy to build. It would need an AC or alternating pulsed DC input - and would be 'single stroke'...

For the coil - assuming you have a power supply that can handle a range of voltages & currents - it would be a useful test to start with a smaller diameter, and add layers - to see what the difference it actually makes. So start off with perhaps 1Kg of copper, then 2Kg, 4Kg etc... More copper should mean less input power required for the same output...