Replica of Palma's homopolar generator

[sigis]

There is Replica of homopolar generator. Still not working, problems with leaking of mercury. Also mercury is very poison. Now we will try Indium alloy. Biggest problem is to avoid leaking with very high rotation like 25000 rpm. Appreciate for advices how to solve this problem. 

[petersone]

Hi Sigis
Beautiful build,if it runs like it looks it will be something special.Hope you get it going soon.
peter

[DreamThinkBuild]

Welcome to the forum Sigis,

Impressive build and machining. Hopefully the mercury leak will only be a very short setback. Are the copper blocks all one piece?

[sigis]

There is two peaces of coper up and down, like in Palma's machine.
Problem with mercury leaking, that is very difficult make small gaps between rotor and teflon separators.

[mikestocks2006]

There is two peaces of coper up and down, like in Palma's machine.
Problem with mercury leaking, that is very difficult make small gaps between rotor and teflon separators.

Hi sigis,
Can you provide few more specifics about leakage, and where exactly does it occur and when? Maybe a blowup schematic of the areas in question could be of more help to better identify the problem and possible solutions?
You only need enough conductive liquid to bridge the gap between the outer edge of your copper rotor and the facing area of the corresponding pickup stator. Making the gap small enough but not too small (account for surface tension, wetting and laminar vs turbulent dynamic states of the conductive liquid, rotational speed related, ofc and thermal expansions etc) would be helpfull.
It maybe easier to pour in the liquid slowly as the rotor is already in motion and slowly speeds up to avoid cavitations, air bubbles, slowly achieve a continuous film/body of fluid in the gap. You may also want to include a drain port at the bottom to start removing it as the rotor slows down and gravity starts taking over causing the liquid to gather at the lower area and overflowing from the sides.

Agreed with posters above on mercury, and as already noted possibly a Eutectic Alloy of Ga-In,  24.5%In might be better for safety and overall handling, it’s liquid above 15-16 deg C

Do you have any vibration issues (liquid conductor present) and if yes at what speeds?

I hope this helps
Mike