Identification please

Re: Identification please

William Duffield

https://www.worthpoint.com/worthopedia/antique-wood-magneto-hand-crank-line-87529560

Exact

Gary Smyth

William,

Thank you. Perfect.

Didn't know the name so no clue. Paid $13 (lowered from $15). Not what I thought it was, but now I have an accurate reference/description. Not a haul but maybe, MAYBE worth what I paid. Minimal loss if all else fails. Not much demand for original use. I'll try to think of a repurpose.

Thanks for the quick response.

Re: Exact

John McGaw

Might be good for harvesting earthworms in the yard...

Hummmmmm

Gary Smyth

At 300v (I'll have to find amps) I wonder if wet dirt/grass might harvest me too.

Re: Hummmmmm

John McGaw

Given that the voltage will be between the leads, as long as you are not in the path you should be fine. Old phone magnetos used to be the way to bring earthworms to the surface for use as fishing bait. I'm not sure what the open-circuit voltage on one of those was but under load they certainly managed 75-90V, that being the traditional AC signalling voltage on POTS.

Re: Exact

Lee Schierer in McKean, PA

My dad made an earthworm shocker from an old hand cranked field telephone generator. We used it for many years. You had to be careful not to zap them too much or they would die shortly after harvesting.

Lee

Re: Hummmmmm

John K Jordan

>>> Old phone magnetos ...

I still have a couple of old field phones, still in working condition. I looked at the output with an oscilloscope once and I forget the base voltage but I remember seeing spikes to 400 volts.

As kids we had a couple of 3 and 4 magnet

Keith Newton

Hand crank generators from old phones that we would take turns seeing who could hold on the longest starting slowly, then getting a little faster each round. I being the youngest always won, due to the fact that my older brother, knowing he couldn't take his next turn would trick me into holding on, then he would spin for all he was worth, then run away yelling I can't take anymore.

One morning before I woke up, I heard stifled giggles at the foot of my bed. The plan they had cooked up was for one brother to hold the wires to my foot, while the other cranked. They were solid little copper wires and the middle brother holding the wires, in his exuberance stabbed me so hard that besides being shocked had the double sensation of two punctures.

You know your not going to have a good day when it starts off like that. ha

Re: As kids we had a couple of 3 and 4 magnet

John K Jordan

A great electricity demonstration is to mount a crank generator like that on a board with a rheostat and a small light bulb from a flashlight. I'd turn the rheostat way down for zero current and let a kid crank. Cranked easy. Then I would slowly increase the current to the lightbulb and it got harder and harder to crank.

It was a great illustration of how much actual work goes into lighting a single tiny bulb. You can see the "light bulb" go on in their heads as they realized how much actual work it would take to light up a room light!

BTW a easy way to make a shocking demonstration is to use a small transformer. Touch the leads on one coil to a flashlight battery (I used a telegraph key) and a low current/high voltage spike would come from the other coil. Sometime around 1967 I took it to a class at the school and had everyone who wanted to hold hands in a circle with those on the end holding the leads. It was surprising the difference in reaction - some felt a strong shock and some felt nothing! Entertaining and educational.

JKJ

Re: As kids we had a couple of 3 and 4 magnet

AZ in Colorado Springs

We did something similar in small engine repair in high school. The cover with the pull starter was removed from a lawnmower motor. The instructor put his hand on top of the flywheel. The students formed a circle, holding hands, with the last one holding the spark plug wire. The instructor turned the flywheel back and forth, passing the magnet by the magneto. Most of us felt a tingle, but on kid reacted strongly, jumped back, and wound up on his butt on the floor.

Reeeely Good

Mark Mandell - Gone Round In New Jersey

way for a teacher to get fired or sued or (probably) both.

Showing the current generation with a light bulb hookup is a great way to demonstrate; administering electro-shock therapy to students is just stupid.

These days yes...

John in NM

that would probably get a teacher fired, sued, or both.

The basic idea is no different than christmas bulbs in series though, and sound in terms of physics if not prudence. If that one kid wasn't just hamming it up, which I tend to think likely, then he probably had more conductive shoe soles than the rest.

I still don't care much for this kind of demonstration however. To me it falls under the category of a little learning being a dangerous thing and could lead some of the students to do stupid things later, not understanding the science behind why it worked the first time and not the second.

Nothing New

Mark Mandell - Gone Round In New Jersey

I left the classroom 40 years ago. The local union ran workshops on do's and don'ts in classroom procedures that could risk kids' injuries. In the ceramics room we needed special ventilation for glazes, a key lock on the pug mill, and regular current leakage checks on the electric potter's wheels. One message that was pounded home repeatedly was that different kids had different strengths, weaknesses, and sensitivities. The "eggshell skull" rule always applied. I'd be very surprised if anything has changed over the decades.

Re: Nothing New

John in NM

Very few safeties when I went to school, a mere 30 years ago. The kind of demonstration Andy mentioned wouldn't have surprised me a great deal back then, but it would now. I would guess that local rules still vary, but not as much as they used to.

Re: Nothing New

AZ in Colorado Springs

And I never wore a bike helmet before my kids were big enough to ride two wheelers (so of course I had to set a proper example) , but here I am.

(ALWAYS wore a helmet on the motor cycle, though.)

Eeeek! It's . . . LATIN!!!

Mark Mandell - Gone Round In New Jersey

"en loco parentis"

That teacher is (was back then too) expected to exercise the care and protective decision-making with regard to that student that his/her competent and caring parent, who the teacher is replacing on a temporary basis, would exercise.

"Yo, hold this little wire," just doesn't come close.

Haha!

John in NM

You should have seen some of the times my dad said "Here kid, watch this"

He would be better described by "Un loco parentis!"

But I am basically agreeing with you - this is not the sort of thing teachers probably should have been doing, even though the physics was sound (given enough children to get the desired voltage drop across the group). You never know when a kid will not bother with the gritty details of calculation when showing the kid brother and end up with a fried sibling and a lot of explaining to do.

Re: Haha!

John K Jordan

Absolutely right. Most of our high school "extracurricular" geek activities were not sanctioned by the school or the teachers. That includes the mercury fulminate episode and the bottle rocket launchers made from snare drum stands.

Although I did get into a squirt bottle battle with one chemistry teacher, great fun until he backed into a cart full of small glass bottles of indicator solutions. Wow, you should have seen the kaleidoscope of swirling colors on the floor.

JKJ