Doc76016

Yes you are right. Unfortunately my circuit diagram labels it incorrectly.

 

My other mistake was to assume CVR(W) & CVR(T) had the same charging arrangement. Although they are broadly similar I didn't realise the CVR(W) used the a vibrating contact regulator which is rather crude unlike CVR(T) with CAV 440 module at the heart of the panel.

Are the two regulator types interchangeable?

I thought the testing procedure was fully covered in the pdf I put in my previous post?

Indeed. However, as I lack the proper test cable or access to such, I am forced to improvise. Your PDF file is extremely helpful and very much appreciated. Reading through it again I see that I stopped one step short. I have now completed the testing on page 25. I get 4.2v as described in step 4. However, at step 6 I detect no voltage. I still need to test the cable before concluding that the alternator is defective.

Thank you,

mdh

Well, I finally got a few moments to do some more troubleshooting. I decided to see if the alternator is actually providing voltage to the distribution box. After studying the system I decided to disconnect the large cable at the distribution box. I then fitted appropriate wires to the pins and inserted them into the sockets being careful to maintain the correct routing and leaving the pins exposed so that I could attach a voltmeter. I assumed that the main charge would be from the two very large pins. With the engine running at approximately 1500-1800 rpm I measured only 4.2v. I also measured every possible combination of plugs and ground. I got 4.2v at a couple of places and 3.1v at another couple and nothing at the remainder.

Does this indicate a bad alternator or cable from the alternator or is my major premise of 28v at the large pins wrong?

Thank you,

mdh

Hello

 

Yes, another ferret is showing as 03CC37 in the UK. It's not uncommon for numbers to be messed around with.

 

If you can send or PM me the hull number I will try to get to the bottom of the number issue. I have a ferret register, albeit not fully complete.

 

Cheers

 

Matt

I am going to attempt to attach a pic of the plate attached to the hull. However, i am unsure if the size is small enough to be allowed. If you are unable to read it please let me know. Underneath the plate the hull is inscribed with 2126 9 59.

JUST VIEWED THIS REPLY AND REALIZED THE PIC IS UPSIDE DOWN. Let me help...

CAR SCOUT RECCE FV701H MK2/3 MODEL B

1952 CONT. No DAIMLER VEH. No 76MS83 CODE No

CLASS OF REPAIR DATE WKSPS. No INSPECTION

REBUJLD 23BW 7/72

2126959

mdh

Mark at Green Machine Surplus does very good quality manuals http://www.ekmpowershop5.com/ekmps/shops/greenmachines/cvrw-fox-125-c.asp

Thank you again for the assistance. Will check out Mark's site.

mdh

Hello

 

Yes, another ferret is showing as 03CC37 in the UK. It's not uncommon for numbers to be messed around with.

 

If you can send or PM me the hull number I will try to get to the bottom of the number issue. I have a ferret register, albeit not fully complete.

 

Cheers

 

Matt

Will get the hull number in a few days. At the moment I am away from home base for a bit.

mdh

I had the same issue looking for "CMP" or "FGT". I didnt realise you could use the wildcards either.

 

 

One alternative is to use google using the site filter. e.g. search terms of "site:hmvf.co.uk CMP FGT"[/]

 

 

And I learn yet another helpful trick! Thank you.

 

mdh

The search word has to be at least 4 letters long, the way to get round that is to add a wildcard like fox*

Thank you. That does indeed help. I didn't realize that wild cards were allowed.

mdh

Have you seen these manuals on Andys excellent ferret site:

 

http://www.ferret-fv701.co.uk/manuals.htm

 

May I enquire about the registration number for your ferret?

 

Regards

 

Matt

A thousand thanks! That is an extremely useful link. Just what I was seeking. Hopefully I can find a counterpart for the Fox.

The number stenciled on my Mk2/3 Ferret is 03CC37. However, I have discovered that number is also on another Ferret in the UK.

Again, thanks for the help.

mdh

I have most of the necessary manuals for my Ferret and Fox. However, they are poor quality reproductions and many diagrams and photos are extremely unclear. Is there a source for GOOD quality manuals out there somewhere?

Thanks,

mdh

I can't seem to get the search function to work properly. Specifically, if I search all forums and posts for "fox" nothing is found. However, I know that there at least a few posts containing "fox" because I have made them and have received replies containing "fox". It's probably something simple I'm overlooking, right?

mdh

We had a problem a few years back where the wire to one of the pins in the Alternator socket was broken..

I did find a few connections that were partially broken and resoldered them but that wasn't it.

mdh

It might seem a stupid question, but have you checked to see if the alternator drive belt is still intact?

Not a stupid question at all. Unfortunately, the belt is intact so it's not that simple.

mdh

This should answer all your questions.. http://hmvf.co.uk/pdf/FoxChargingSystem.pdf

Wow! Fantastic resource! I have downloaded it and will study it carefully. A million thanks.

mdh

Well, I pulled the distribution box and opened it up. There seemed to be only a slight bit of corrosion on the contacts of the big relay. I gingerly cleaned that up. There were several smaller relays. They seemed to be fairly clean so I left them alone. I then replaced the box but nothing has changed. The alternator light is still on and the ammeter does not move. A VOM shows no charge delivered to the batteries. With the engine running I applied a battery charger to the batteries but the light did not go out or dim and the ammeter did not move at all. Does this give you a clue as to what might be the problem? I'm going to remove the box again this weekend and see if the main relay will operate if i apply voltage directly to it.

Thanks,

mdh

I did mine yesterday.

 

It' probably the main contactor that has white fur on the copper contacts. You will hear the large relay go 'clunk' as the revs rise...but still no light.

 

A quick scrape with 400 grit emery sorted the problem in a few minutes. I check the contact resistance to make sure that there is no debris still on the contacts. It should read close to zero ohms when you push the contacts together. It is also quite common for there to be a fault in the ammeter shunt circuit...just check the battery volts whilst running to see if it is really not charging.

 

It's best not to mess with the regulator relay unless you are good at re-setting the cut-in voltage. It is just about impossible to clean the contacts without disturbing the relay spring. The tension on this spring determines the voltage that the alternator connects to the battery. Get it too low and the battery drains through the alternator. Get it too high and it will seriously overcharge.

Don't forget that these alternators are rated at 200 amps! It is also capable of outputting voltages in excess of 200v dc if you get it really wrong.

 

Incidently I worked out that the fan drive coupling on a Fox has to absorb 50hp when charging at full whack!

 

I have reset a Fox regulator using a variable voltage power supply and lots of dummy resistors (variacs) simulating the alternator windings. It should cut-in at about 28v.

 

Good luck.

 

Jon

Thank you for your helpful and informative reply. I'll check it out this weekend.

mdh

My FV-721 is not charging the batteries. I have heard that a common problem is "dirty contacts" on the bucking regulator in the distribution box. I have removed the distribution box from the vehicle. Before I open it up does anyone have any tips?

Thanks,

mdh

Hello, everyone. Only recently discovered this site. I own a Ferret, a Fox, and a US M35a2 (deuce and a half). I live in Dalworthington Gardens, a small town of 2,300, surrounded by Arlington, a city of 360,000. My only other experience with military vehicles was as an enlisted man in the US Army where I was allowed to drive M151s, M715s, and M113s. Perhaps you could consider one additional piece of military hardware i crewed as a vehicle: I later served as an officer in the US Air Force and got a couple of hundred hours in the back seat of an F-4 Phantom II fighter aircraft. I look forward to discussions here and will try to contribute as much as my meager knowledge allows.