alternator negative

[Smelly]

I know this is probably a daft question but I'd rather ask it than get it wrong and cost me money.

 

i'm fitting an alternator controller... I've got to connect a wire to the negative but the book's guide doesn't seem to cover my brand...

 

I've got a W connection that currently has nowt attched to it is that it?

 

i'd ring sterling but I've no credit on mi phone and no money left to buy some.

 

Snibble... be ye out there?

 

Boat's a scouser with an isuzu engine, the alt's not got a brand but the back of the regulatorr's got "uniport" written on it. The book say's it's a 110A but the alt say's it's 80A so I'm not trusting it..

 

Ta?!

[Smelly]

Having re-read the destructions I note that I can fit the black wires to the alternator case...

 

I'll stop panicing...

 

I've paid someone to solder the wires onto the reg, having killed one alternator in years passed, only to find they'd used the wrong cable, 2A instead of 10A, so i've just had to re-do that, which was easier than it was last time... however as I said above, i'd rather ask than f**k it up...

[David Schweizer]

I know this is probably a daft question but I'd rather ask it than get it wrong and cost me money.

 

i'm fitting an alternator controller... I've got to connect a wire to the negative but the book's guide doesn't seem to cover my brand...

 

I've got a W connection that currently has nowt attched to it is that it?

 

i'd ring sterling but I've no credit on mi phone and no money left to buy some.

 

Snibble... be ye out there?

 

Boat's a scouser with an isuzu engine, the alt's not got a brand but the back of the regulatorr's got "uniport" written on it. The book say's it's a 110A but the alt say's it's 80A so I'm not trusting it..

 

Ta?!

 

 

The W connection is for a Tachometer (if you have one)

Edited November 29, 2007 by David Schweizer

[Sir Nibble]

Morning, I don't have a set of instructions in front of me but I would suggest you put the negatives on the battery. Reason being that the whole idea of battery sensing is to measure what the battery gets and regulate on that rather than measure at the alternator so it compensates for the difference. Well you can have differences on the -ve too.

[John Orentas]

Yes there probably isn't a Neg connection but as you have found out the case conducts directly to the engine block..

 

There are a few exceptions those alternators made to an MoD specification or true marine units, they will have a large connector about the size of the Pos one and I am sure clearly marked.

[Noah]

I know this is probably a daft question but I'd rather ask it than get it wrong and cost me money.

 

i'm fitting an alternator controller... I've got to connect a wire to the negative but the book's guide doesn't seem to cover my brand...

 

I've got a W connection that currently has nowt attched to it is that it?

 

i'd ring sterling but I've no credit on mi phone and no money left to buy some.

 

Snibble... be ye out there?

 

Boat's a scouser with an isuzu engine, the alt's not got a brand but the back of the regulatorr's got "uniport" written on it. The book say's it's a 110A but the alt say's it's 80A so I'm not trusting it..

 

Ta?!

Hi Smelly

 

The label "Unipart" suggests that the alternator may be a Lucas replica like my Lucas (Unipart) A127. Often these have no manufacturer's markings at all to identify them. On mine one of the connector posts on the alternator is stamped B- for negative. These markings can be difficult to see, and connect, on some engines without moving the alternator.

 

Be sure that the connections you make are secure and use shake-proof washers. I recently had the negative come loose and it caused an intermittent fault that was hard to trace.

 

Noah

[Sir Nibble]

"Unipart" Is a generic car spares supplier who were linked to BL Austin / rover, I thought they were defunct. "UniPOINT" is a supplier of replacement alternators and starters and unfortumately they appear to be identified only by paper labels that don't last long.

[Smelly]

Ta all, it seemes to be working now...

[jakub]

"Unipart" Is a generic car spares supplier who were linked to BL Austin / rover, I thought they were defunct. "UniPOINT" is a supplier of replacement alternators and starters and unfortumately they appear to be identified only by paper labels that don't last long.

 

 

 

Exactly. I am the one with UNIPOINT alternator (70 A). Tha label does not exist. Alternator is two years old. It has 3 bolts on it and 3 blades (2 bigger ones, 1 small). It has funny charging current - 14.5 V.

 

Something like a small black box - like external regulator (?) - is attached to the back of the alternator. This regulator is connected to the alternator internal space by the black plastic covered connection which I cant remove and to the W marked connection which is also the alternator negative.

 

Two bigger blades are not connected to anything. One smaller blade is connected to split charge relay.

 

I emailed Unipoint regarding a manual - no response.

 

Any help in this matter? Is that correct wiring? Any manuals available anywhere? Is it possible to connect this alternator as "battery sensing" using one of those bigger blades?

 

Thanks

Jakub

[Sir Nibble]

Exactly. I am the one with UNIPOINT alternator (70 A). Tha label does not exist. Alternator is two years old. It has 3 bolts on it and 3 blades (2 bigger ones, 1 small). It has funny charging current - 14.5 V.

 

Something like a small black box - like external regulator (?) - is attached to the back of the alternator. This regulator is connected to the alternator internal space by the black plastic covered connection which I cant remove and to the W marked connection which is also the alternator negative.

 

Two bigger blades are not connected to anything. One smaller blade is connected to split charge relay.

 

I emailed Unipoint regarding a manual - no response.

 

Any help in this matter? Is that correct wiring? Any manuals available anywhere? Is it possible to connect this alternator as "battery sensing" using one of those bigger blades?

 

Thanks

Jakub

Picture mate. If you can't take a photo givvus a sketch.

[Sir Nibble]

Upon reflection, it sounds like this MAY be an A127, this small black box, about 30X20X10mm? single wire vanishing inside alongside the +ve stud?

[jakub]

Picture mate. If you can't take a photo givvus a sketch.

 

 

Link to the picure (sorry I cant paste pictures in here for some reason):

 

http://picasaweb.google.co.uk/KubaUK/Roboc...909910179629010

 

Connections on the picture:

 

 

1. black, thick cable next to ...vanishing cable from the regulator - ve +

2. the closest cable with the yellow thing on it - ve - ... and the regulator is connected there as well.

3. thinest brown cable goes to ignition key and then to split charge relay (Durite 180 A - seems working fine).

 

Just below blak box on the side of the alternator there is letter W (not visible on the picture).

 

Alternator had until recently a label on it saying UNIPOINT 70 A and its roughly 2 years old.

 

Charging current 14.5 V. Belt recently changed - not slipping.

[chris w]

As Snibble thought, it IS an A127 alternator. The little black box is a supression capacitor. The thin brown wire is the charge light connection. The thick black wire with the yellow crimp is the negative and the other thick wire on the other terminal is the positive output. The "W" connection is for your tacho. The metal unit, with fins cast into it, screwed to the back of the alternator is the internal regulator.

 

Complete refurb kits for these are available very cheaply on Ebay - new regulator, new diodes, new bearings etc

 

Chris

Edited December 6, 2007 by chris w

[jakub]

Thanks,

 

What for are the wider blades then?

What external regulator should I buy for it?

 

Thank you,

Jakub

[chris w]

The other wide blades are both positive outputs connected (internally) to the big thick output lead. You don't need to use these - they are for other applications.

 

As regards external controllers, there are a number. I happen to use a Sterling PDAR controller and am very happy with it. It also has both battery AND alternator over-temperature alarms and cut-outs and a remote display giving lots of running parameters.

 

Chris

Edited December 7, 2007 by chris w

[Sir Nibble]

If the brown cable does indeed go to the ignition key and thence the split charge relay, then the relay willbe pulling in when ignition is on and passing current from the domestic battery to the starter. This is bad for the relay. It will also be trying to charge from the alternator field diodes, this is bad for the alternator. Do you not have a warning light? The higher charge voltage will also be explained by the fact that the regulator senses from this terminal.

[jakub]

If the brown cable does indeed go to the ignition key and thence the split charge relay, then the relay willbe pulling in when ignition is on and passing current from the domestic battery to the starter. This is bad for the relay. It will also be trying to charge from the alternator field diodes, this is bad for the alternator. Do you not have a warning light? The higher charge voltage will also be explained by the fact that the regulator senses from this terminal.

 

No I dont have warning light. The relay is connected to the ignition somehow. Its funny but even when engine is stationary and i will put ignition into the ON position the ammeter shows current approx 5 A going out of the battery. Is that the current going to the starter motor you mentioned?

 

My eletrical scheme is there:

 

http://picasaweb.google.co.uk/KubaUK/Roboc...415594097696546

 

At the moment the regulator circut is disconnected. The regulator is roughly 20 years old I recon.

 

Hope it will be helpful.

 

If not - let me know i will try to explain/draw better one.

Thanks for help.

Jakub

Edited December 7, 2007 by jakub

[Sir Nibble]

OK, Got that, the 5A you are seeing is going through the alternator rotor (field) winding, there should be a warning lamp inserted in this line. Currently, (no pun) the alternator internal regulator is seeing the battery voltage measured at the ignition switch. The internal diodes which SHOULD be feeding the field and from which the regulator should sense are trying to charge the battery and they are not up to the job and one day they will go Phut! when you blow the horn or summat. Insert a warning lamp into that line and see what happens to your charge rate and get back to us, we can look at the voltage/current/rpm and make an informed decision as to whether or not an external reg would be of benefit.

[chris w]

Also the relay appears to be wired such that it is ON (ie: connecting the two batteries) immediately the ignition is turned ON. It would be better (IMHO) to run the relay from the output of the alternator so that two sets of batteries are only connected for charging once the alternator is running.

 

Chris

[jakub]

If the brown cable does indeed go to the ignition key and thence the split charge relay, then the relay willbe pulling in when ignition is on and passing current from the domestic battery to the starter. This is bad for the relay. It will also be trying to charge from the alternator field diodes, this is bad for the alternator. Do you not have a warning light? The higher charge voltage will also be explained by the fact that the regulator senses from this terminal.

..

OK, Got that, the 5A you are seeing is going through the alternator rotor (field) winding, there should be a warning lamp inserted in this line. Currently, (no pun) the alternator internal regulator is seeing the battery voltage measured at the ignition switch. The internal diodes which SHOULD be feeding the field and from which the regulator should sense are trying to charge the battery and they are not up to the job and one day they will go Phut! when you blow the horn or summat. Insert a warning lamp into that line and see what happens to your charge rate and get back to us, we can look at the voltage/current/rpm and make an informed decision as to whether or not an external reg would be of benefit.

 

Also the relay appears to be wired such that it is ON (ie: connecting the two batteries) immediately the ignition is turned ON. It would be better (IMHO) to run the relay from the output of the alternator so that two sets of batteries are only connected for charging once the alternator is running.

 

Chris

 

Must say I am a bit lost. I dont know too much about diodes and internal parts of alternator. Lets put it that way...All I know is that is something wrong in the way my thin brown wire gets from the alternator to the relay. I could easily rewire it differently. For example directly alternator-relay like Chris suggest or.... like on this picture:

 

http://www.kampenwagen.co.uk/images/Split_charge_relay.gif

 

...if I only knew how.

 

There is no warning light, but will it change anything (is it not ONLY indication?). Shall i put warning lamp between ignition and alternator or between ignition and relay, or maybe without connecting it to ignition at all..?

 

I would appreciate If you could possibly give me rough idea how to wire this connections. I am having START-OFF-ON-HEATER type of ignition switch. UNIPOINT alternator (Lucas A127 type as you established). Relay Durite 180 A that connects both batteries when switch is in ON position (this could be changed as Chris suggests). I am waiting for a shunt ammeter to arrive.

At the moment I want simple/reliable system; for a time being without external regulator so that I could find if I need one at all. I dont know if my alternator is battery-sensing or not and if it is not how can I make it battery sensing?

 

Thank you

Jakub.

 

Ps. I should buy you a drink.

[chris w]

With respect Jakub, you should leave well alone as your electrical knowledge is obviously somewhat basic and you may end up causing expensive damage to your alternator and/or batteries if you wire things incorrectly. It's also very difficult to keep explaining more and more complex steps to someone without at least their having a reasonable knowledge of electrical and electronic systems.

 

You'd be better of IMHO to try to make contact with a fellow forum member who has better electrical knowledge and who is geographically located near to you.

 

Chris

 

PS: where are you based?

Edited December 8, 2007 by chris w

[jakub]

With respect Jakub, you should leave well alone as your electrical knowledge is obviously somewhat basic and you may end up causing expensive damage to your alternator and/or batteries if you wire things incorrectly

 

You'd be better of IMHO to try to make contact with a fellow forum member who has better electrical knowledge and who is geographically located near to you.

 

Chris

 

PS: where are you based?

 

I am based in Brentford , London. I think is just the matter of me not being able to explain correctly what my wirng looks like. Its difficult without good sketches. My batteries ARE wired correctly to the alternator. The thing that left for me to understand is the thin wire going out of the alternator. Snibble said it is wired incorrectly so I simply wanted to now HOW should I wire it so that everything is OK.

for example : Is that directly to terminal 86 of the relay with the warning light on it?

 

I hoped that is it not that difficult to anwser that question.

 

I do agree that I dont have electronical knowledge about the internal components of the alternator. If I had I would not need help I think.

 

Thank you,

Jakub

[Sir Nibble]

Righto, I shall try to explain.

The internal regulator is connected to a trio of diodes which pass part of the alternator output to it. The regulator uses this for two things:

1) To supply the field winding

2) To read the output voltage.

The regulator reading this voltage from within the alternator makes it "Machine sensed".

This diode/regulator connection is also connected to the small blade terminal on the alternator. In connecting this to the ignition switch you have replaced the internally generated supply with an external feed from the battery.

You should have, a feed from the ignition switch to a warning lamp and thence splitting into two to the alternator small blade terminal and the split charge relay. The warning light passes a small current to supply the field winding as 1) above, when the alternator reaches its cutting in speed a voltage arises from the diode trio to fully energise the field and relay, and in going +ve, denies the lamp a return path to -ve and it goes out.

So:

1) a warning lamp is more than just an indicator, it is required to pass the small current needed to "Pump prime" the alternator field

2) the relay will only pull in when the alternator is actually charging.

Get it working that far and we can then progress towards battery sensing or whatever else seems like a good idea IN THE LIGHT OF the correctly wired system.

It is possible that this wrong wiring is someones misguided attempt to sidestep the failure of one or more of the diodes in the trio, or that it may have resulted in a diode failure, the behaviour of the warning light when correctly wired will tell us a story about that.

Edited December 10, 2007 by snibble

[chris w]

Just as a small addition to Snibble's excellent instructions: the warning lamp you use needs to pass at least about 250mA for it to "excite" the alternator. If in doubt, wire a 47 ohm 5 Watt resistor in parallel with the warning lamp.

 

Chris

[Sir Nibble]

the warning lamp you use needs to pass at least about 250mA for it to "excite" the alternator. Chris

ie, 12V 3W bulb.