Free runnig alternator?

RoadScholar · Sep 6, 2015

I've never had a reason to ponder this question before.

I have completed an engine rebuild, now it's time to wire up the beast, but I want to verify that the engine is sound before covering the motorcycle with its' electrical various circuits.

My plan is to wire a total loss ignition circuit to make sure that my engine has the correct cam timing, is leak free and that the cylinders are in team mode. I want to run this motorcycle for 20-30 minutes up and down a reasonable rev range to break in the rings (assuming that its' oil tight); I have a private road circuit to do this on. BUT there is no easy place to mount the reg/rec without making a bracket or dissembling the rear fender, which I don't want to do unless the engine is sound.

Here is the question: Can I run the engine with the three alternator AC outputs hanging in the breeze without harming the stator?

grandpaul · Sep 6, 2015

Shouldn't hurt anything at all, but do tape off the ends to prevent arcing anywhere.

comnoz · Sep 6, 2015

RoadScholar said:
I've never had a reason to ponder this question before.

I have completed an engine rebuild, now it's time to wire up the beast, but I want to verify that the engine is sound before covering the motorcycle with its' electrical various circuits.

My plan is to wire a total loss ignition circuit to make sure that my engine has the correct cam timing, is leak free and that the cylinders are in team mode. I want to run this motorcycle for 20-30 minutes up and down a reasonable rev range to break in the rings (assuming that its' oil tight); I have a private road circuit to do this on. BUT there is no easy place to mount the reg/rec without making a bracket or dissembling the rear fender, which I don't want to do unless the engine is sound.

Here is the question: Can I run the engine with the three alternator AC outputs hanging in the breeze without harming the stator?

It would be a good test of the stator's insulation as the voltage on the open circuit may rise to 300 volts. It should handle it with no problem.

Three 25 ohm 25 watt resistors would keep the voltage levels down. Jim

Bernhard · Sep 7, 2015

RoadScholar said:
I've never had a reason to ponder this question before.

Here is the question: Can I run the engine with the three alternator AC outputs hanging in the breeze without harming the stator?

If I did that, knowing my luck, I’ll more than likely burn the alternator out

Triton Thrasher · Sep 7, 2015

So far as I know, you can run it open circuit or short circuited for as long as you like.

gripper · Sep 7, 2015

Why not just remove the stator altogether? That's what I would do if I was trying to achieve what you are.

Anonymous · Sep 7, 2015

Q. Can I run the engine with the three alternator AC outputs hanging in the breeze without harming the stator?
A. Yes but why not hang the reg/rec on a peice of wire/string under the carbys so you maintain full battery charge and ignition function while 'bedding' the rings?
Ta.

swooshdave · Sep 7, 2015

What would you do if the engine doesn't work?

Jeandr · Sep 7, 2015

Running the alternator with the wires not connected to anything is OK. If you then use a Podtronic or similar rectifier/regulator, never run it without a battery.

Jean

RoadScholar · Sep 8, 2015

gripper said:
Why not just remove the stator altogether? That's what I would do if I was trying to achieve what you are.

There is a fair amount of work involved in doing this. I'm not opposed, but it would seem from a majority of the responses that I can just let the stator run free.

RoadScholar · Sep 8, 2015

needing said:
Q. Can I run the engine with the three alternator AC outputs hanging in the breeze without harming the stator?
A. Yes but why not hang the reg/rec on a peice of wire/string under the carbys so you maintain full battery charge and ignition function while 'bedding' the rings?
Ta.

I am not concerned about battery charge. I have a new battery that will easily provide me 20 minutes of run time, so why complicate things?

texasSlick · Sep 8, 2015

Way back in the dark ages of the '60's, before Zener diodes and electronic voltage regulators, and before the nanny state gobberment mandated we run with lights on, (not say'n that isn't a good thing), I ran my stator open circuited (used a switch to open the stator leads) in the daytime to prevent battery boil-over. I ran many miles and many years that way .... No problemo.

Slick

Nortoniggy · Sep 8, 2015

If the alternator isn't connected to anything then no current can flow because there is no circuit for it to flow into. No current = no heat = no damage.

Ian

RoadScholar · Sep 8, 2015

Nortoniggy said:
If the alternator isn't connected to anything then no current can flow because there is no circuit for it to flow into. No current = no heat = no damage.

Ian

That is the consensus, but you have a magnetic field rotating inside a set of conductors; electrons are bound to move if not get excited with nowhere to go, hence my initial question as I have never not wired the complete circuit prior to operation; I just don't want to invest too much time in this project unless its going down the path of a V 1.0 success.

texasSlick · Sep 8, 2015

Road scholar wrote:

. "That is the consensus, but you have a magnetic field rotating inside a set of conductors; electrons are bound to move if not get excited with nowhere to go, hence my initial question as I have never not wired the complete circuit prior to operation; I just don't want to invest too much time in this project unless its going down the path of a V 1.0 success".

Nothing to worry about .... the rotating magnet inside the stator coils will develop an electron potential.

The term potential means it can "potentially" move electrons, but nothing will happen if the circuit is open. However, as others have noted, the voltage potential can get very high as much as 300 volts, therefore you must insulate the terminals from each other, and from earth.

I rode my Atlas open circuit stator trans-continental .... how much more assurance do you require that nothing bad will happen?

Slick

RoadScholar · Sep 8, 2015

Thank you to all respondents.

As far as I'm concerned: Case Closed, I'll go ahead with my tests with the alternator disconnected, but protected.

grandpaul · Sep 9, 2015

RoadScholar said:
...electrons are bound to move if not get excited with nowhere to go...

If that were the case, you'd have electrons jumping out of wall sockets all day long!

Free runnig alternator?

RoadScholar

grandpaul

comnoz

Bernhard

Triton Thrasher

gripper

Anonymous

Guest

swooshdave

Jeandr

RoadScholar

RoadScholar

texasSlick

Nortoniggy

RoadScholar

texasSlick

RoadScholar

grandpaul

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