all charged out.

[r8516874]

I wonder if anyone can help me with sorting my charging system. I've read Clive's paper and although it's very helpful I'm still stuck.

I'd like to know what are the connections inside the generator panel, and where they go to.

I'd also like to know if anywhere sells parts for FFR landrovers

[fv1609]

You'll need to tell us whether you have a 40A or 90A system & what is the Mk of your Generator Panel?

[r8516874]

Its a 90 Amp system and I think the generator panel is mk 4 but I'm not sure.

[r8516874]

By the way, Clive, well done with your paper. brilliant bit of writing.

[fv1609]

Its a 90 Amp system and I think the generator panel is mk 4 but I'm not sure.

 

Ok the circuit diagram is on page 5 of article 1.

 

The connections are on page 10 of article 3.

 

Have you followed the diagnostics in article 3?

 

Did the system work once or has it never worked in your ownership?

 

Have you or previous owner made some 'modifications' to the wiring?

 

You say it is not charging. On what basis is that, the charge light still on, no movement of the ammeter if you have radio batteries fitted, no voltage increase if you rev?

 

Do you have a multimeter so you can measure volts & ohms?

 

It is important to verify if it is a Mk 4 as it is significantly different inside from earlier Mks. In general, but not necessarily, a Mk 4 installation has a single ammeter in the shunt box rather than 2 ammeters on the dash.

[r8516874]

The system has been working but it looks like its been bodged.

There are two ammeters in the dash but neither of them are wired up. I have two extra boxes. One with 3 outlets, a big fuse and red and back terminals on the top. As does the other but this one is smaller with 2 relays inside.

The generator panel is mounted inside the truck cab instead of in the back.

The charge light is on and the engine revs make no difrence to the voltage.

I do have a multimeter, so I can test volts, ohms etc.

I'd like to know the connections on the out going side of the generator panel (earth, vehicle batteries, radio batteries, charging light) inside the panel.

There are no radio batteries fitted but I'd like to make everything how it was.

I have put the generator into a workshop to be tested, but I don't know how much joy they will have.

Could my generator panel have failed?

[fv1609]

With two ammeters in the dash it would have been intended to work with a Gen Panel No.9 Mk 3 or earlier. But this way round a Mk 4 panel which is transistorised should work.

 

You need to establish which Mk of panel you have for any detailed fault finding. If it has a third smaller socket on the box it will be a Mk 4.

 

Bear in mind that the -ve output only becomes earthed only after it comes out of the gen panel & at the shunt box. It is easy for these connections to become undone or damaged..

 

I would be surprised if a normal workshop would be able to cope with testing an alternator that has no internal regulation. So you might get no joy there I'm afraid.

 

When you get it back I can give you resistance readings to check for.

 

Some photos of all these bits would be of help.

[r8516874]

I have just been to check and your right it is a mk 3 panel.

 

I'm trying to get some photos for you to see what i've got left of the system.

 

what would the resistance readings be for? Can they check that the generator is working?

[fv1609]

what would the resistance readings be for? Can they check that the generator is working?

 

Well you'll be able to test the integrity of the field winding & to some degree the output windings & the associated diodes & confirmation that the carbon brushes are making contact.

 

The final verification is connection to the gen panel. The main function of that is to regulate the current in the field winding, this controls the electromagnetic field which in turn regulates the output voltage. The other function of the gen panel is to connect the vehicle & radio batteries in parallel & to the generator output, there is some radio interference supression as well.

[r8516874]

Well you'll be able to test the integrity of the field winding & to some degree the output windings & the associated diodes & confirmation that the carbon brushes are making contact.

 

So you just check that there is continuity and therefore it should work. Is it the diodes that get damaged and stop the generator working?

 

So where do the vehicle and radio batteries connect inside the generator panel. I've been looking at some pictures and I think the second/outgoing plug is missing and the vehicle batteries were just wired direct from the gen panel to the starter relay and earth.

Where does the vehicle battery lead go after the shunt box?

[fv1609]

So you just check that there is continuity and therefore it should work. Is it the diodes that get damaged and stop the generator working??

No its not as simple as that, continuity could mean something is shorting. The diodes to function exhibit a different resistance depending on whether they are conducting a forward or reverse current. So applying an ohmeter will mean in one direction you have high resistance the other way low resistance. The reading that you get will depend on the sensitivity of the meter (ohms per volt).

 

The diodes can be damaged by prolonged overload (ie overheating), transient high voltages produced with no load ie running the alternator with no load (eg no battery) & nasty voltages resulting from electric welding

 

So where do the vehicle and radio batteries connect inside the generator panel. I've been looking at some pictures and I think the second/outgoing plug is missing and the vehicle batteries were just wired direct from the gen panel to the starter relay and earth. Where does the vehicle battery lead go after the shunt box?

 

You can trace what goes where in the gen panel from the circuit diagram. A good medical principle is no treatment without a diagnosis, I think you need to follow through the flow diagnosis to pin down whether the fault is the gen or gen panel. I feel you are fighting a battle on several fronts. :-)

[r8516874]

I obviously have a couple of problems. not knowing where the fault/faults are and the system not being complete in the first place.

I think completion of the system is my first goal, then i can run through these tests.

Do you know anywhere i can buy the cable from the generator panel to the shunt box and from that to the ammeters and the vehicle batteries?

I have been to the workshop and got the generators back. What tests are you suggesting?

I think I have a wiring diagram in a manual I've got.

 

Jim

[fv1609]

Jim, it would be nice to have all the leads & cables as nature intended. It would be satisfying to rip out the bodgeries with a vengance, but perhaps it would be worth just getting it back to the state that it was when it was last charging. Once that is sorted then move onto reinstating the proper wiring. Otherwise you could be introducing more unknowns into the system because you will be unlikely to find NOS cables, they will invariably be take offs from a system that might have had faults.

 

Cables do turn up there is a steady trickle of people who for various reasons decide to convert their 24v system to 12v. A useful source of bits would be to join this forum. You have to register, you don't have to be a member of the association.

 

http://forum.emlra.org/index.php

 

I don't know what is missing & bodged can you post pics? If you have the main gen to gen panel cable unnscrew the gen end & carefully check the soldered leads are still good. Also do a pin to pin continuity test for each wire within the cable & check there are no shorts. Really you should use a Megger to check for leakage between wires & the braiding as well, but at least put your ohmeter on max resistance & check for leakage.

 

I think the circuit diagram of the Gen Panel No3 is in one of the articles.

 

Was the workshop able to give any help on the generator? I'll dig out resistance readings.

[r8516874]

Thanks for the advice on the forum, I've joined up. Lets hope I find somthing.

 

Unfortunatly the workshop wasn't any help at all, I dont think normal foke have dealings with systems like these. The resistance readings would help, I will have my fluke with me and I can borrow a megger from work.

 

I've tried to add some pictures, so I hope they help. One I think is the shunt box and the other with the cover open just contains two relays. Of cause I've also got the generator, the generator panel and the cable to join the two.

[fv1609]

Jim ok well the double shunt box, of what I can see of it, looks normal enough.

 

I have no idea about the nonsense in the other box which as you know is not part of the original installation. In fact those boxes were mounted on the wings of my Lightweight for the storage the coax cable & plug when not plugged into the wing mounted ATU (Aerial Tuning Unit).

 

OK some ball park resistance readings for Generator. Select ohms negative probe on pin W. Appx readings.

Positive probe in turn on P, T & R - 30 ohms. X - 100 ohms. F - 130 ohms.

 

Reverse the probes & repeat should be greater than 10k.

 

Both probes on U & V (either way round) - 15 ohms.

 

Let me know what you get & if its different I'll try & tell you where the fault lies.

 

I've started work on an All Charged Up No.4. This will provide new info with simplified circuit diagrams enhanced with colour & newly labelled photos in colour. The articles originally appeared in Windscreen before it went colour. There will be a bit of repetition so that it could be a stand alone article without having to refer back to the articles & it will try to simplify tests but provide more info for someone with a multimeter to have a go. Together with more advanced tests for perhaps a knowledgeable friend to embark on as well.

[fv1609]

Just had a thought Jim, you didn't say which Mk of Generator you have.

 

Those readings I quoted are only valid if you have a Mk A, Mk 1 or Mk 2. If you have a Mk 3 you will get no readings on pins P, T & R.

[r8516874]

Clive,

 

Well I've got some very strange results.

Firstly I think I've got a mk 3 generator.

The generator that was on the landy when it stopped charging read O/L on all positions apart from U-V, 27ohms and W-X, 1.836ohms.

So I guess we can saftly say that one's dead.

 

But the spare on I had, with a dodgy bearing, read diffrently.

W-P, 4.0m ohms then climbed to 4.7m ohms

W-T, 4.0m ohms then climbed to 4.7m ohms

W-R, 4.0m ohms then climbed to 4.7m ohms

W-X, 21.56m ohms

W-F, 4.1m ohms then climbed to 4.9m ohms

U-V, 17ohms.

 

All these readings really have confused me. The only part I understand is the cable from the gen to the panel is good. there is still no volts with the generator with the dodgy bearing in and the panel wired up how it was.

 

I have a feeling the whole system may have given up, or at least there is more than one fault.

Tomorrow night I'm going to try and work my way through the step by step fault finding guide, so I'll let you know how that goes.

 

Jim

 

P.S

All charged up No.4 sounds good to me.

[fv1609]

Clive,

 

Well I've got some very strange results.

Firstly I think I've got a mk 3 generator.

The generator that was on the landy when it stopped charging read O/L on all positions apart from U-V, 27ohms and W-X, 1.836ohms.

So I guess we can saftly say that one's dead.

 

Jim I'll answer this first part here & then reply to the other in a minute as it is easy to get befuddled with all these readings going on.

 

U-V is a bit high. This is your field winding which should be 15 ohms +/- 0.5 ohms. The brushes may be worn & its not making a good contact on the slip rings. Take 3 readings by rotating the shaft to 3 different positions & take the average.

 

W-X should read much higher when you reverse the probes. If its the same it points to the main diodes. Pity you don't have a Mk 2 then P, T & R would allow some internal assessment of the diodes individually.

 

Back in a minute.

[fv1609]

But the spare on I had, with a dodgy bearing, read diffrently.

W-P, 4.0m ohms then climbed to 4.7m ohms

W-T, 4.0m ohms then climbed to 4.7m ohms

W-R, 4.0m ohms then climbed to 4.7m ohms

W-X, 21.56m ohms

W-F, 4.1m ohms then climbed to 4.9m ohms

U-V, 17ohms.

 

All these readings really have confused me. The only part I understand is the cable from the gen to the panel is good. there is still no volts with the generator with the dodgy bearing in and the panel wired up how it was.

 

I have a feeling the whole system may have given up, or at least there is more than one fault.

Tomorrow night I'm going to try and work my way through the step by step fault finding guide, so I'll let you know how that goes.

 

Jim

 

P.S

All charged up No.4 sounds good to me.

 

U-V sounds much better

 

The other readings, are you saying these are megohms?

 

What are all other readings with the probes reversed?

 

Don't despair. Logic will triumph, probably.

 

Yes been on ACU 4 again today:-)

[r8516874]

Sorry Clive, it was a small m so they read milli ohms.

With the probes reversed the reading where higher, I can't remember exact figures. I'll check again if it will help.

Are there any internal checks I can do on the generator panel?

At what point would I find the 28 volts for charging? After the generator, or out of the panel?

[fv1609]

Sorry Clive, it was a small m so they read milli ohms.

With the probes reversed the reading where higher, I can't remember exact figures. I'll check again if it will help.

Are there any internal checks I can do on the generator panel?

At what point would I find the 28 volts for charging? After the generator, or out of the panel?

 

Jim I'm surprised with the milliohms that you can read that low so accurately. I find I can easily gain an ohm if the test prods & plugs aren't tight, clean & me pressing hard with the probe. Well let's see what they are the other way round.

 

As for the Gen Panel I think its established you don't have a Mk 4 (ie transistorised regulator) It is unlikely to be a Mk 1. So it is important to establish whether it is a Mk 2 or a Mk 3 as they differ significantly.

 

Mk 2 has an additional relay to isolate the supply to the field winding on switch off. It has a normal relay for the battery isolating.

 

Mk 3 has no field relay but has a CAV Type BCK relay to isolate the batteries from each other & the generator. This has a second 'bucking' winding in the opposite sense it is only operative if one or both of the batteries are connected the wrong way round. If this happens what was a blocking diode in each supply from the battery now conducts & reverses the magnetic field in the BCK causing it to open avoiding serious damage.

 

So we need to establish which you have.

 

Well the gen panel should provide 24v to pins U & V when the generator is running, with it disconnected if you push down on the BCK relay then it should give output to U & V.

 

If you have the earlier Mk 2 you will need to press down on the battery relay & the smaller field isolating relay. This looks like the voltage regulator & is sat next to it. It is the one nearer the main socket.

[r8516874]

There is a good chance I am wrong, I shall double check the readings again tomorrow.

I'm positive that I have a mk 3 panel, but I will try and get a picture to confirm it. It looks the same as the one on page 13 of all charged up part 3.

Does 24 volts come from the generator pre-rectified then? Through pins u and v?

[fv1609]

Does 24 volts come from the generator pre-rectified then? ?

Yes , the main output does & the seperate 24v to operate the BCK relay to connect both batteries together & to the main output. But there is nothing coming out of the pins U & V on the generator that is the input.

 

Through pins u and v?

Pins U & V have 24v from the generator panel it is just this supply that comes from the voltage regulator, This supply goes into U & V on the gen that supplies the field winding that in turn alters the magnetism that in turn regulates the main output mirroring & 'amplifying' the changes from the voltage regulator.

[r8516874]

Clive I have the full readings for you, and I hope you can make sense of them, because I can not. I have put the new readings first followed by the readings I took last time. They are both from the same generator.

I'm sorry, the readings were in megaohms not milliohms as I said last time.

 

Firstly with the negative lead on pin W.

P= 22.3Megaohms/4Megaohms

T= 22.3Megaohms/4Megaohms

R= 22.3Megaohms/4Megaohms

X= Open line/21.56Megaohms

F= 28.5Megaohms/4.1Megaohms

 

Then with the positive lead on W.

P= 0.807Megaohms

T= 0.807Megaohms

R= 0.807Megaohms

X= 1.884Megaohms

F= 2.87Megaohms

 

Then, the U and V results averaged with turning the generator over.

U-V= 24ohms

V-U= 26.8ohms

 

 

I hope you can decifer something from these readings clive because it is all Greek to me. How could I tell what is at fault? Do the batteries provide the 24volts for the field windings? If they do I wonder if their not wired up correctly?

[fv1609]

Jim, you said earlier you had a Mk 3 generator, in which case you should get no readings from P, R & T as the pins are not connected to anything! Are you absolutely certain it is Mk 3 generator?

 

Assuming it a Mk3 then all I can think of to explain that is moisture, grime or corrosion around the plug pins. I assume you are measuring this directly on the generator not on the connecting cable. But if there is no connection it is curious that you get different readings from your previous & by reversing the prods different readings again. Are you happy that your battery in the multimeter is up to scratch on all resistance ranges?

 

The readings with +ve lead on W should all be pretty high, so ok there.

 

But the readings with -ve lead on W should all be in the 100 ohm region. So something very wrong there

 

U-V & V-U should be identical either way round a bit high but not outrageous, although spindle position can cause variation. This is measuring the field winding resistance.

 

So all I can visualise is either a problem in the multimeter or inside the generator itself burnt out diodes/wires or desoldered wires & some grot around the plug pins. This is hard to envisage as it was working ok recently & you would have said if there was smoke or the smell of overheating.

 

Yes the batteries provide the power for the field winding & after regulation the winding draws about 0.5 amps.

 

The alternative way to approach this is to use a bulb & battery. Get a prod with a lead & connect to a 24v 5w bulb & then the other side of the bulb to one terminal of a 24v battery. Connect a prod & lead to the other terminal of the battery.

 

Connect +ve prod to W

Scratch the paint off each of the 3 heatsinks & in turn touch the -ve prod onto the heatsinks.

Bulb should light up.

Reverse prods bulb should not light up.

 

Connect +ve prod to X

Scratch the paint off each of the 3 heatsinks & in turn touch the +ve prod onto the heatsinks.

Bulb should light up.

Reverse prods bulb should not light up.

 

Those two tests are for the 6 main diodes.

 

 

Connect the -ve prod to F

Scratch the paint off each of the 3 heatsinks & in turn touch the +ve prod onto the heatsinks.

Bulb should light up.

Reverse prods bulb should not light up.

 

That tests the 3 low power diodes that energise the battery relay.

 

If it fails on those tests you need to go inside the gen & have a look around!

Edited February 12, 2010 by fv1609