Alternator Paralleler Circuit

[Sir Nibble]

Sorry, my office interweb connection blocks useful things like diagrams. Where are these capacitors connected? W to earth? Reason I ask is 'cos W is a single phase, one of the main output phases and I wonder if there may be a certain speed where the frequency will be just right to make that a virtual short, and also whether that may be part of your low voltage issue.

[Smelly]

Don't worry, there weren't any diagrams.

 

Both capacitors are now connected from w to earth in parallel to their respective relays. Do you mean my current low voltage charging issue Sir Nibble or the previous with the ow voltage through the switch.

 

If it was the latter then there were'nt any caps in place then.

 

Finally... what is an uf when it's at home?

 

edit... You've got me worried now so a couple of questions...

 

1 to rule out the Sterling I can test voltages at D with the W connection switched on and switched off, how quickly can I expect to see a rise and am I at risk of killing everything if I do?

Edited May 28, 2009 by Smelly

[Sir Nibble]

I mean the current low voltage issue. I am wondering what proportion of the capacitor discharge is making its way out elsewhere and appearing as a spike and upsetting the voltage sensing.

uf is micro farads and describes the capacitance of the component.

[RLWP]

I mean the current low voltage issue. I am wondering what proportion of the capacitor discharge is making its way out elsewhere and appearing as a spike and upsetting the voltage sensing.

uf is micro farads and describes the capacitance of the component.

 

Here, is this any use to you?

 

 

µ

 

 

 

Richard

[Smelly]

I didn't ask the other question as well...

 

How hot does the alt reg get?

 

I ask because if I do end up doctoring it then the easiest way I can see is to break the connection above the spring holder, isolate it and solder to the contact at the top of the holder, instead of breaking into the spring holder. I bit of plastic between the two sides of the soldered contacts would work nicely but would it melt?

[Sir Nibble]

Thats probably a more involved way of doing it!

If you don't fancy cutting the brush holder etc like Chris has done, carefully drill a hole in the top of the brush holder where you can see the tiny discoloration from where the brush lead was spotwelded on. The brush will now slide free with lead and spring. Solder a piece of wire to the brush lead, use a heat shunt such as long nosed pliers to prevent the solder wicking up the brush lead. Sleeve the joint and pass the wire through the hole and secure with a drop of superglue. The reg does not get very hot at all.

[WotEver]

I wonder if there may be a certain speed where the frequency will be just right to make that a virtual short.

 

That's a good point. At 1000Hz a 470uF cap is presenting only around 0.3r.

 

Would perhaps a diode in series from the W terminal be required (along with another 0.7V drop of course)? Or is there one already inside the regulator?

 

Tony

 

Edit to note that the diode already in the diagram between the latch relay coil and the switch could easily be moved to immediately after the fuse from the W terminal (before the capacitor). Er, if required...

Edited May 28, 2009 by tony@hdheaven.co.uk

[Gibbo]

That's a good point. At 1000Hz a 470uF cap is presenting only around 0.3r.

 

Would perhaps a diode in series from the W terminal be required (along with another 0.7V drop of course)? Or is there one already inside the regulator?

 

Tony

 

Edit to note that the diode already in the diagram between the latch relay coil and the switch could easily be moved to before the capacitor.

 

That's just a big red herring I'm afraid.

 

1. Makes no difference which side the diode is on.

2. The impedance of the cap only matters when fed with AC which it will only be fed with for about 1/2 cycle by which time it wil be charged up.

3. Even if the impedance of the cap did matter (which it doesn't for these purposes) the alternator would simply blow it to pieces.

 

Gibbo

[Sir Nibble]

That's a good point. At 1000Hz a 470uF cap is presenting only around 0.3r.

 

Would perhaps a diode in series from the W terminal be required (along with another 0.7V drop of course)? Or is there one already inside the regulator?

 

Tony

 

Edit to note that the diode already in the diagram between the latch relay coil and the switch could easily be moved to before the capacitor.

I'm afraid I'm not hugely au fait with such things but it occurs to me that the discharge of the caps would find it's way through W and the rectifier to B+ and may produce a spike that is fooling the regulator.

At 1000Hz a 470uF cap is presenting only around 0.3r.

Well within the alternator speed range then.

[Gibbo]

I'm afraid I'm not hugely au fait with such things but it occurs to me that the discharge of the caps would find it's way through W and the rectifier to B+ and may produce a spike that is fooling the regulator.

 

It can't because of D1 (assuming that too hasn't been moved/changed/turned round)

 

Gibbo

[WotEver]

(assuming that too hasn't been moved/changed/turned round)

 

 

Hey guys,

 

So are we now concluding that Pete's last diagram (this one) is good to go?

 

Thanks,

Tony

[Gibbo]

 

Hey guys,

 

So are we now concluding that Pete's last diagram (this one) is good to go?

 

Thanks,

Tony

 

I think so and I think Pete thinks so.

 

Unfortuantely it seems to me that all the problems have been red herrings as a result of the diagram not actually being followed.

 

Gibbo

[Smelly]

I think so and I think Pete thinks so.

 

Unfortuantely it seems to me that all the problems have been red herrings as a result of the diagram not actually being followed.

 

Gibbo

 

And I'll happily admit to that and apologise.

 

I'm actually using Chris's version and as to my revelation about the 2 caps I was wrong... It was the cap across the contactor that made the difference. having got home I've just inadvertently trashed the cap across the latch relay, with the contactor cap off it didn't work, but with the contactor cap connected it does!

 

I do think that Pete's will work, and have explained my error during the week above. Its just it seems by that time I'd already p*s*ed everyone off...

 

edit... having just read up I notice a comment about being "blown to pieces". Is that literally? I assumed I'd caught the other cap with something as I'm prone to cocking up, however you've got me thinking... the cap case was in two bts and there's hairy stuff everywhere.

 

Can I stop prostrating myself now?

Edited May 28, 2009 by Smelly

[Gibbo]

And I'll happily admit to that and apologise.

 

I'm actually using Chris's version and as to my revelation about the 2 caps I was wrong... It was the cap across the contactor that made the difference. having got home I've just inadvertently trashed the cap across the latch relay, with the contactor cap off it didn't work, but with the contactor cap connected it does!

 

I do think that Pete's will work, and have explained my error during the week above. Its just it seems by that time I'd already p*s*ed everyone off...

 

Can I stop prostrating myself now?

 

Well I don't see why. You've confused the hell out of me. I have no idea what you have and haven't got now

 

If you're using Chris's version then the cap will make no bloody difference whatsoever. If it does make a difference, then you might think you are using Chris's version. But you're not.

 

Gibbo

 

PS. Try to bear in mind that a decent electronics engineer can predict exactly, to any required precision, what a given circuit will and won't do. There is no guesswork or trial and error involved. It is an absolute science. But if you get given a circuit, and actually build something different, then there is nothing but guessing left to work on.

Edited May 28, 2009 by Gibbo

[RLWP]

edit... having just read up I notice a comment about being "blown to pieces". Is that literally? I assumed I'd caught the other cap with something as I'm prone to cocking up, however you've got me thinking... the cap case was in two bts and there's hairy stuff everywhere.

 

Yes, literally blown to pieces. You have the evidence in your hands.

 

Richard

 

Not as spectacular as the big paper-in-a-can one I blew up once. Lots of bits of paper everywhere when the end blew out...

[Gibbo]

edit... having just read up I notice a comment about being "blown to pieces". Is that literally? I assumed I'd caught the other cap with something as I'm prone to cocking up, however you've got me thinking... the cap case was in two bts and there's hairy stuff everywhere.

 

Reverse polarity.

 

Amusing aren't they!

 

Gibbo

 

Edit: Unlike the case of the latch relay, if you don't have the diode across the contactor coil, then that relay does store enough energy to blow the cap up when it switches off.

Edited May 28, 2009 by Gibbo

[Smelly]

Well I don't see why. You've confused the hell out of me. I have no idea what you have and haven't got now

 

If you're using Chris's version then the cap will make no bloody difference whatsoever. If it does make a difference, then you might think you are using Chris's version. But you're not.

 

Gibbo

 

PS. Try to bear in mind that a decent electronics engineer can predict exactly, to any required precision, what a given circuit will and won't do. There is no guesswork or trial and error involved. It is an absolute science. But if you get given a circuit, and actually build something different, then there is nothing but guessing left to work on.

 

I take it all back... You're right, but I am using a variant with the latching relay in the line from W on the positive side of the relays. i have drawn a diag and having swapped machines in a mo will sc

 

Well I don't see why. You've confused the hell out of me. I have no idea what you have and haven't got now

 

If you're using Chris's version then the cap will make no bloody difference whatsoever. If it does make a difference, then you might think you are using Chris's version. But you're not.

 

Gibbo

 

PS. Try to bear in mind that a decent electronics engineer can predict exactly, to any required precision, what a given circuit will and won't do. There is no guesswork or trial and error involved. It is an absolute science. But if you get given a circuit, and actually build something different, then there is nothing but guessing left to work on.

 

I take it all back... You're right, but I am using a variant with the latching relay in the line from W on the positive side of the relays. i have drawn a diag and having swapped machines in a mo will scan it once I've switched to the other machine.

[Smelly]

my scanner won't work in vista... HP PSC 1215, I've just hit two different forums who both said "no".

 

so I don't know whether to walk away and leave you all in peace, but I will try one last time. W switches through the latching relay, out of the coil end and to the conntactor coil which it is in parallel with the 470uf cap and a 1n5402 diode.

 

If you want me to leave you in peace just say...

[Gibbo]

my scanner won't work in vista... HP PSC 1215, I've just hit two different forums who both said "no".

 

so I don't know whether to walk away and leave you all in peace, but I will try one last time. W switches through the latching relay, out of the coil end and to the conntactor coil which it is in parallel with the 470uf cap and a 1n5402 diode.

 

If you want me to leave you in peace just say...

 

I have PM'd you with a solution.

 

Gibbo

[smileypete]

 

Hey guys,

 

So are we now concluding that Pete's last diagram (this one) is good to go?

Hi,

 

I think that's as good as it gets. I'm confident it will work if built as is.

 

That said, I've thought of another circuit that has a reasonable chance of working without needing the capacitor, though am not as confident about it as the the one above. It does use more or less the same bits, will post a diagram tomorrow evening.

 

cheers,

Pete.

[WotEver]

will post a diagram tomorrow evening.

 

Thanks Pete

 

You gonna get Smelly to test it?

 

Tony

[Smelly]

You gonna get Smelly to test it?

 

Tony

 

I didn't need persuading last time but I will this...

 

Anyhow mine works and last night the voltage got up past 14.3 so I think my concerns are allayed just got to find the right setting on the Sterling to push past the alt reg.

[smileypete]

Thanks Pete

As promised, here it is:

 

 

The basic idea is to overcome the problem that the latch relay and contactor need a lot more 'oomph' to close initially, than hold closed.

 

So with this circuit, when the push switch is pressed, the latch relay and contactor get full battery voltage across them. Though the latch relay has a lamp in series (which I'll come to in a bit), this will be cold and so at low resistance when the push switch is pressed.

 

After the push switch is released, the output from W should hold the latch relay and contactor closed. If not, then there's always the previous circuit... or plan C

 

Lamp 1 is to ensure that as the output voltage from W drops, the latch relay opens before the contactor, otherwise the contactor may 'chatter'. If the latch relay does not close initially or stay closed, the power rating of Lamp 1 should be increased gradually.

 

The pair of diodes D1 and D2 can also be formed by using a bridge rectifier with push on terminals, like a KPBC3504 (£2 each).

 

 

You gonna get Smelly to test it?

Hmmm. It sounds like he's pretty happy with what he'd got now, hopefully.

 

cheers,

Pete.

[chris w]

Why all the faffing around with capacitors and light bulbs?

 

The way I did it was so simple..... my switching circuit works immediately (see original diagram) with no problems at all and using the regulator output transistor collector of the alternator with the PDAR connected, to achieve auto switch-off, works beautifully (thanks for Snibble's idea). You seem to understand what needs to be connected where, in this regard Smelly, as you correctly described the mods needed somewhere above.

 

It works, it's not difficult for you, you have all the bits... just go do it - no issues and switches off everytime at 14.35v.

 

Chris

[smileypete]

Why all the faffing around with capacitors and light bulbs?

Read post #423 again. The circuit above has NO capacitors and a single lamp.

 

Also

• Needs no soldering (yes, read the text!)
  
• Needs no dismantling of the alternator
  
• Is capable of paralleling batteries for starting.
  

cheers,

Pete.