# Why aren't homopolar generators more commonly used?

In particular with the advent of HVDC(high voltage direct current). Using mercury(metal), the resistive losses can be greatly reduced. There has even been some experimental research into neon plasma based electrical contacts. They have been used to supply the large currents required by particle accelerators. What is interesting is that AFAIK it is the only type of electric generator that can produce pure, ripple-free DC current(and very large currents as well). One could build a high current output rotary converter using an AC motor coupled to a homopolar generator.

• They are more commonly used, in ships with superconducting cables. I suppose the cost and technology is a factor with very large L/R ratios, high Tesla values etc. – Sunnyskyguy EE75 Jan 1 at 6:32
• @TonyEErocketscientist what about particle accelerators with superconducting magnets? I seek to learn how to build them. – Mr X Jan 1 at 17:40
• what about them? not many of those \$ – Sunnyskyguy EE75 Jan 1 at 18:23
• @MrX how to build a homopolar generator, a particle accelerator, a superconductor or a superconducting magnet? If you're wanting to build a homopolar generator it's probably not out of the question. If they're not common, it's probably because making a good one requires considerable engineering or they're considered to be the best at a specific thing (steady DC at extreme current and moderate voltage), but if either is the case, with some modern materials you can likely build something considerably better than the original version shown in the wikipedia article. – K H Jan 2 at 3:38
• @KH: No, I am not trying to build a particle accelerator. Or even a superconductor/superconducting magnet. But a homopolar generator? That seriously does interest me as a project(using liquid mercury). – Mr X Jan 2 at 16:48