Red light in MKII Carrier
 

Went for a ride today . Not too cold , -12 C. A red light lit up in the instrument cluster between the switches for the engine on and the lights . What does it mean ? Thanks .

Generator is not charging sufficiently. Was it at idle or at full speed? Those generators back then were pretty marginal..add to it that you really don't tension the fanbelts like you do today.
If the light is on at idle but off at higher RPMs, that is perfectly acceptable.

Thanks Rob. It stays lit at cruising speed . So i have a charging problem . I will check the tension on the fanbelt and report back . Also , i installed the blanking board in front of the radiator and the temp eventualy made it to 170 degrees . Is that a good operating temperature in winter in your opinion ? Cheers.

That red light should go on when you turn the ignition switch on, then go off once the engine (and hence generator) are running. If you run the carrier in pitch black that light will give of an eerie faint glow sometimes.

Carriers look particularly fetching with snow in the tracks and bogies, no?

Very “fetching” indeed Bruce ! Snow on her is like mascara on a pretty girl , it enhances appeal .

Don't overdo the tension on the belt. Fords ran fairly loose.

One thing you can do to improve it is to replace the cut out switch on top of the generator with one of the solid state units from Mac's. They had one that also acted as a regulator. Only proviso is if you boost the vehicle with 12 volts, you automatically fry it.
Edited to add: I don't see them on Mac's site anymore, but here is a site with them: http://www.funprojects.com/products/10505v.aspx

170 in the winter is fine.

Thanks again Rob . All Items not in stock . I think it’s a fantom site because the copyright has not been renewed since 2018.

Hallo . Changed the cut-off for a brand new one from Mac’s . No joy . Red light and 0 reading on ampmeter on dash whatever the rpm . Straps are ok and turn . Any ideas anyone ? Thanks .

Can you tell if the generator is putting out anything? If not it would explain the red light and you'd be running off the battery alone.

Bruce , i put the probes of the voltmeter on the battery terminals with the engine running and i get 6 volts . I assume that the geny is not putting out any juice . Am i right ? Should i look for a fuse somewhere or does the generator have to come off ?

It could be as simple as the brushes are worn or dirty. If that is the kind of work you can do, then you will have to pull it off. If not, then you will have to pull it off and send it to an automotive electronics place. Best to find one that has been around for a long time. They likely do not run into a lot of 3 brush generators these days.

Agreed, generators and starters either work or are made to work with a little cleaning and work on the brushes. If it is a catastrophic failure in the windings then you need professional help (or at least I do). Usually a quick look inside will tell you if there's a short, burning or something stuck.

A steady 6V reading (assuming what you are checking connects back to the battery) strongly suggests to me it's the generator not putting anything out.

What's that old trick about reversing the terminals on a generator to make it 'motor' as a way of checking it?

Pulling a carrier generator would be easy enough it it weren't for that friggin fan. You pretty much have to remove it or risk driving one on the blades into the radiator cooling fins. If you do remove the fan first (recommended) then you scrape every bit of skin off your knuckles working the 7/16' wrench between the fan extension and the aforementioned rad cooling fins.

There are simple tests you can do with a multimeter once you have the generator apart and on the bench. Continuity between all of the segments is one of them. Ensuring the windings are not going to ground is another. Then there is flashing of the generator once it is together. In fact, that is something that can be done with it in place on the vehicle and the cut-off disconnected before you take it off. I would have to read up on the third brush type generators though. You need some level of residual magnetism for a generator to work.



If all this is lost on you, then remove it and take it to an automotive shop. They can also put the armature on a growler which instantly tells them if there is a problem. The average home mechanic does not have a growler. I may well be living in the past thinking the automotive shops have them anymore.

The trick I've used many times on my 6V motorcycle dynamos to test them is:-

Take the two wires that come out the dynamo F&D, connect them together and connect them to the live end of a single filament bulb (12V is best for this purpose) Earth the cap of the bulb to the dynamo with crocodile clips and run the engine. The bulb should light up and glow brighter as you rev it up. If it doesn't, As already suggested, check/replace the brushes, clean up the end of the commutator with thinners/switch cleaner etc. The build up of carbon dust and shite can insulate the commutator and or cause the brushes to stick up in their holders.

By the same system you can test/motor the dynamo on the vice by connecting those two same joined wires to the poss of a battery and earth the body to the neg side. The dynamo should motor in the same direction that it charges at.

I've said an awful lot here for what is a very simple test operation. Ron

Have you checked the cut-out relay?

Thank you Bruce , Rob, Ron & Charlie . All very good and most generous advice . All that know me more intimately know what my trade was for 32 years in the service and it was not REME like my father . Charlie , what does that relay look like and where is it located ? Picture ? I will look at the relay before skinning my knukles as Bruce so explicitly described ang bringing the generator to a specialised shop ....Ahahaaaa, thanks Bruce .

Here are pictures of my new cutoff and surrounding wires.Is the cutoff relay the blue «*thingy « to the left of the top picture ? What is the relay’s purpose and what is the description so i can order a new one please ? Many , many thanks .

That blue thingy might be a diode someone put in. It could be faulty. Testing it is easy enough...it is a one way valve for electricity. Disconnect the wire to the screw at the cutoff in order to isolate the diode. Put the leads of a multimeter set to ohms onto each end of the diode. You may or may not get continuity. Then switch the leads around. You may or may not get continuity. One way should give you continuity and the other will not. If you don't get continuity either way, then the diode is your problem. Don't be touching the bare ends of the leads when doing this test...you also have a certain measure of continuity.



You can also do this with a self powered testlight. The DC power should only go through one way.



If the diode is bad, you can toss it and run the wire straight across. I understand why someone put in the diode, although quite frankly, that is what the cutoff is for. Some of the replacement cutoffs are just that....a diode hidden under the cover. That blob on the diode may indicate it is bad, or it may just be bird poop or debris.


Edited to add: It may also be a capacitor, to replace the original filter unit. Either way, toss it and run the wire straight to ground. That blob on the side does not look kosher no matter which it is. You are out in the country....I doubt the lack of a filter will disturb anyones televisions or radios. You could run a short test lead with two alligator clips to see if that is your problem....just attach a lead to each side of the blue thing.


Edited one more time: Or is the blue thing just a blue butt connector? In that case it is likely just a red herring. It should have continuity through it. Pull on both wires going to it and make sure they are tight. If one comes out, you could replace it or you could use solder and heatshrink.

No conductivity Rob . Off it goes . Will report back . Thanks !

1 indicates 0 ohms according to the manual ( yes i had to read the manual .... ) . First time i use one of these . I have other skills but i am learning with the help of my friends from MLU !

I think it is just a sleeve ( Blue plastic ) over a bad joint or connection sleeve . The wires must of come seperated with time . I started the engine , the red light is very bright . When i accelerate the rpm’s the red light fades considerably but it remains on but very faintly . Normal ?

Yep, it is just a plain old butt connector. Join the two wires together and see what happens.

Ohms is a measurement of resistance. One way to do a quick check is to touch the two terminals of the ohmeter together and look at your reading. That is a perfect circuit with little to no resistance. Now check them again on the item being tested. If you are testing a connection, it should be similar to what you got when you touched the two wires together. If you are testing something like an incandescant lightbulb, there will be a resistance....that's what causes it to glow. If there is no movement of the meter, then you have an open circuit or in the above two cases, a bad connection or a burnt out lightbulb.



You do not have to apologize or make excuses for not knowing this Bob. That is why electricians, furnace repair guys, and mechanics can charge $100 plus an hour for their services.

This should mean the generator is putting out a charge. I believe in the manual there is a section in adjusting the 3rd brush to change the output of the generator.

Perhaps this is all it needed.

I was going to suggest that Jordan, and didn't catch that the light did dim somewhat. Good call.


That can be done on the vehicle, but if results are not there, then off to the rebuilders to get the brushes checked and cleaned.



I had an old tamper generator that I used to run a 125v crafstman impact gun off of. I used it to disassemble the 30 M151A2s I bought out in a field back in 87. Everytime I started it I would have to stick my screwdriver onto the segments to get it clean enough to excite the windings. In hindsight I should have took the time to open it and clean things up, but it really only took a few seconds my way.

Many thanks Jordan and Rob . I will look up the manual and try to adjust the 3 brush and report back . Cheers . Bob

see R3 Electrical, UC F1

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Thank you very much Michael R . Very useful information.

Robert, you can do that motoring test with the unit in place as long as you take the belt off. (take the load off)
How the light works: When you turn the key on, the light comes on. (battery voltage) When you start up, voltage coming from the generator pushes in the opposite direction. This stops any power flow and the light goes out. (or nearly goes out)
The round tin on the top of the generator is the cut out. (I think) This opens circuit when the geny output drops to battery voltage and stops the geny from trying to motor when the key is off. The voltage output is adjusted by moving the 3rd (adjustable) brush.
If you drop the belt and "motor" the geny, and it runs, then it is in reasonable condition, so you shouldn't have to pull it out.
Make sure you have good earths on the components.
Thats about all I can come up with without doing some study.
Read up on it.

Thank you very very much Lynn , most helpful information . This will save me a lot of trouble. Nice receiving advice from New Zealand . I had a good time working with the crew of one of your frigates ( Te Kaha ) two years ago in Victoria BC . Decent men and women , dedicated warriors and protectors of your country .

Robert,

The generator was set up years ago to just produce a trickle charge. There is not a large demand from the generator other than topping up the battery. Probably after all these years, it's time to adjust the movable brush, maybe clean up the commutator as well.

Perry