stator output 13.8V

[Greenbraes]

just a quick one to the electrical guys...I have just done a very quick check and with the engine at 5000rpm the volts at the battery terminal is 13.8V, at 1100rpm it is 12.4V...does this merit somemore checks? I am planning on removing the engine soon to paint but am trying to find out everything I can before I do....for info the bike up to recently has sat for 17 years...the engine is now running OK and sounds very smooth but the bike is unfit to even run round the block so it is just run up in the garage

cheers for any help

RB

 

[allojohn]

just a quick one to the electrical guys...I have just done a very quick check and with the engine at 5000rpm the volts at the battery terminal is 13.8V, at 1100rpm it is 12.4V...does this merit somemore checks? I am planning on removing the engine soon to paint but am trying to find out everything I can before I do....for info the bike up to recently has sat for 17 years...the engine is now running OK and sounds very smooth but the bike is unfit to even run round the block so it is just run up in the garage

cheers for any help

RB

It's most likely the R/R acting up and not a stator issue.

 

[tkent02]

Some of the connections may be corroded, a little extra resistance will do that.
Some bikes work fine and last a long time and never get to 14v.

If you don't want parts to fry, clean everything in the system whether it needs it or not.

 

[Greenbraes]

cool...will clean up the conectors and see what that does...cheers for the info

RB

 

[salty_monk]

and if you have the headlight switch you have a long wire that goes up to it from the stator & back that you can simply unplug and take out of the system. Should be good for 0.3v-0.4v at idle in my experience....

 

[SqDancerLynn1]

An extra ground from the reg to the battery can raise the voltage too !!

 

[earlfor]

just a quick one to the electrical guys...I have just done a very quick check and with the engine at 5000rpm the volts at the battery terminal is 13.8V, at 1100rpm it is 12.4V...does this merit somemore checks? I am planning on removing the engine soon to paint but am trying to find out everything I can before I do....for info the bike up to recently has sat for 17 years...the engine is now running OK and sounds very smooth but the bike is unfit to even run round the block so it is just run up in the garage

cheers for any help

RB

12.4v at 1100 rpm and 13.8v at the battery are precisely what it should be. Its normal.
If you have a nearly dead battery, charging voltage will usually be around 14.5-14.8, but as the battery becomes charged, resistance increases and voltage is between 13 and 14v on average.

by the way, those voltages are rectifier DC voltages. The stator produces three phase AC current with 80v on each phase totaling 240v AC

 

[Steve]

The stator produces three phase AC current with 80v on each phase totaling 240v AC

Good intent, but not quite accurate.

I know you were pointing out the error in the title, but then it took a turn "south".

Yeah, each leg produces about 80 VAC, but they don't add up to 240.

Posplayr or one of the other electrical engineers would have to chime in to give you an accurate number, but it won't be 240.

.

 

[Killer2600]

Good intent, but not quite accurate.

I know you were pointing out the error in the title, but then it took a turn "south".

Yeah, each leg produces about 80 VAC, but they don't add up to 240.

Posplayr or one of the other electrical engineers would have to chime in to give you an accurate number, but it won't be 240.

.

They never add up, due to the way the stator and regulator are wired, the output from the stator will always be one of the three phases.

 

[tom203]

They never add up, due to the way the stator and regulator are wired, the output from the stator will always be one of the three phases.

No, it's very much a combo affair ! Here, have some fun



http://www.windstuffnow.com/main/3_phase_basics

 

[posplayr]

they add to zero is the closest answer because 80VAC@0deg + 80VAC@120deg + 80VAC@240deg= 0 Volts

But adding the voltages is not particularly instructive. However, it does indicate why the central node on a Y connected stator is nominally zero (i.e. Neutral)

 

[elrico]

Ohms Law: AC Generator

Ohms Law: AC Generator

If all three generator phases measure 80Vac at the given engine rpm.Then:80(used now as just a formula #) squared=6400 in 1st. phase+6400 2nd.phase+6400 3rd.phase=19200,then find the square root is =138.56 Vac (MAX generator circuit voltage output to RR.)

 

[tom203]

If all three generator phases measure 80Vac at the given engine rpm.Then:80(used now as just a formula #) squared=6400 in 1st. phase+6400 2nd.phase+6400 3rd.phase=19200,then find the square root is =138.56 Vac (average generator circuit voltage output to RR.)

138.56 Vac ! Let's hope not! The open circuit test (phase to phase) only really proves that the windings aren't shorted on themselves, or grounding out somewhere, or just individually open circuited. The real testing is when you put a load on stator- i.e. feed it to R/R and its loads. Any current flow in stator windings drops its output voltage way down- at idle speeds, there's barely enough voltage output to maintain battery in a happy state.

 

[Killer2600]

No, it's very much a combo affair ! Here, have some fun



http://www.windstuffnow.com/main/3_phase_basics

Thanks but if you pay close attention to my wording that info doesn't apply because the stator is already wired and 3 leads are your output,

they add to zero is the closest answer because 80VAC@0deg + 80VAC@120deg + 80VAC@240deg= 0 Volts

But adding the voltages is not particularly instructive. However, it does indicate why the central node on a Y connected stator is nominally zero (i.e. Neutral)

If all three generator phases measure 80Vac at the given engine rpm.Then:80(used now as just a formula #) squared=6400 in 1st. phase+6400 2nd.phase+6400 3rd.phase=19200,then find the square root is =138.56 Vac (average generator circuit voltage output to RR.)

My my my, someone is challenging posplayr let the games begin

I got my chips on posplayr

 

[allojohn]

I (and I hope many others here) find this stuff utterly confusing but at the same time fascinating. Enjoying this thread and similar immensely.

 

[JayWB]

If I remember my AC theory correctly, the 80 volts is ALREADY a DC equivalent. If you actually check the AC waveform you'll see that it actually peaks at 80 * 1.414.

The DC equivalent number is just the average (RMSD) of the area under the rectified waveform.

But that was over 30 years ago...

 

[Killer2600]

If I remember my AC theory correctly, the 80 volts is ALREADY a DC equivalent. If you actually check the AC waveform you'll see that it actually peaks at 80 * 1.414.

The DC equivalent number is just the average (RMSD) of the area under the rectified waveform.

But that was over 30 years ago...

I wouldn't call it DC equivalent but if you want to I understand. Just remember or know there is a difference between Root Means Squared (RMS) (1/√2) and Average (2/Pi). You also need to know what your meter measures, not all meters read "True RMS" - the ones that do list or advertise the "feature"

 

[tom203]

Thanks but if you pay close attention to my wording that info doesn't apply because the stator is already wired and 3 leads are your output

You can believe anything you want- I gave you a simple link to help your understanding of 3 phase stuff. It's NOT 3 single seperate phases- their interconnection creates a distinct output- adding diodes makes life grand.

 

[Killer2600]

You can believe anything you want- I gave you a simple link to help your understanding of 3 phase stuff. It's NOT 3 single seperate phases- their interconnection creates a distinct output- adding diodes makes life grand.

Thanks again but I already understand what 3-phase is. 3-phase is indeed three individual phases, hence three windings, their relation is they are 120? out of phase with one another but otherwise ideally symmetric. But that doesn't matter, what I am pointing towards is there's no combination you can hook up your three stator output wires that will give you a voltage greater than the measurement of one of the phases (2-wire hookup). As posplayr pointed out if you add the 3-phases together you get 0 volts AC. Again this is from your pre-wired stator, I'm not taking about wiring a wye or delta coil/transformer from scratch.

 

[tom203]

In this stator layout ( wye connected- three wire leads), you will always be measuring the combined output of TWO phases, not one; this is why it's used- it gives you a higher voltage which is useful at low revs to at least get some charging ability.