Help needed with Hyde Generator

[Paul-R]

@steve, what about this?  10k rpm
http://cgi.ebay.com/FLEXIBLE-SHAFT-ELECTRIC-GRINDER-AND-ROTARY-CARVER-TOOL_W0QQitemZ250354992006QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item250354992006&_trksid=p3286.c0.m14&_trkparms=72%3A1205|66%3A2|65%3A12|39%3A1|240%3A1318|301%3A0|293%3A1|294%3A5
Mark

Its a heck of a grinder for $74. But does it actually do 10,000
with any appreciable power? (I would not want to be around if
a grinding wheel had a chip out of it, and someone cranked it
up to that speed).

How much power to you expect to need, Steven? Probably
difficult to estimate. Can the apparatus be in a reduced
pressure casing to reduce wind resistance? Heat?
Paul

[Steven Dufresne]

@Mark,
Sweet! Thanks man. It'll be a shame to take it apart but sometimes you've gotta suck it up and cut.

Its a heck of a grinder for $74. But does it actually do 10,000
with any appreciable power? (I would not want to be around if
a grinding wheel had a chip out of it, and someone cranked it
up to that speed).

How much power to you expect to need, Steven? Probably
difficult to estimate. Can the apparatus be in a reduced
pressure casing to reduce wind resistance? Heat?
Paul

@Paul,
I'll be spinning two 2mm thick by 27cm diameter plastic rotor disks with megnetizable steel segments krazy glued to them. See the photo of my current version on the first page of this thread for some idea. I'll be ramping up the speed slowly, which it looks like is possible with this motor, so there's no big starting torque. Given that, I don't think I'll need much power. However, if you look back at the patent diagram I attached in my first post you'll see that the rotor disks will be within an electric field (item 16 is negative or ground, item 18 is positive for example) and so there may be some coulomb forces to overcome, possibly even some high frequency jerking. The voltage across the whole thing will be around 2kV.

I'm not sure what you mean by reduced pressure casing. I do plan on having a casing as in the patent drawing. I don't anticipate much heating around the rotor disks, but haven't thought about it much. As for the motor itself, I expect if it can handle the torque, then the 6000RPM should be well within its design limits.
-Steve
http://rimstar.org   http://wsminfo.org

[Paul-R]

By reduced pressure, I mean to ask if you are running it in a semi vacuum.

This rotor will need serious balancing - really serious balancing.
And not only static balancing, but dynamic balancing as well.
You may need a couple of extra discs on the shaft for this purpose. Do
you have a university with a good Mechanical Engineering
faculty reasonably near by?

[Steven Dufresne]

By reduced pressure, I mean to ask if you are running it in a semi vacuum.

Ah, thanks for clarifying. The answer's no, just regular air pressure.

This rotor will need serious balancing - really serious balancing.
And not only static balancing, but dynamic balancing as well.
You may need a couple of extra discs on the shaft for this purpose. Do
you have a university with a good Mechanical Engineering
faculty reasonably near by?

I was planning on first getting the disks mounted on the shaft and then rotating them at low speed while arranging a marker near enough the disk edge to see any places where it is either out of round or being pushed by out of balance centrifugal force. I'd then trim wherever there were marks and repeat.

I did once use my existing vacuum cleaner motor once to spin a pot up to 8400 RPM in these experiments:
http://rimstar.org/sdprop/rot/rotchgcyl1/rotchgcyl1.htm
That pot was mounted right on the motor shaft. I figure since these rotors will also be on the motor shaft, 6000-7000 RPM should be okay. I do have two nearby universities with mechanical engineering departments but I'll see how I do first.

For safety, I have a 1/4" thick plexiglas barrier which I stand behind along with safety glasses on. You can see it in the photos on the above webpage.

Now that Mark has pointed out that these mini bench grinders exist, I've since found two more on amazon.com. I checked the local hobby shops and hardware stores this morning but no joy there. So I'll shop online a bit more and then buy one.
-Steve
http://rimstar.org   http://wsminfo.org

[Mark69]

@steve, no sweat, keep us informed of your progress 

Mark