More dynamo issues.

[Phil B]

1939 neg earth NH350

No output on meter or bulb test. Comm cleaned, brushes ok, bakelite between segments rebated, flashed batt +ve to F, at which it “motored” on the bit of play/backlash.

I can’t find what to do next.

Here’s some meter readings taken just now.

F to earth 3.26 Ohms

D to earth 0.7 Ohm

D to F 3.8 Ohms

F to comm segments avg 3.5 Ohms

D to comm segments 0.5 Ohms avg

Zero V output at any revs.

All wired as per the diagram as far as I can tell.
Any alarm bell? Any advice? Tests? Suggested meter readings?

Screwdriver pointing to F. Disconnected from main loom during testing, outputs taken from linking D&F and running through known good bulb (tested) to earth.

Thanks all in advance.

[nevhunter]

Unhook both wires and Flash D and put a connection between F and D and it should run at full output. From your circuitry you can see that will put full volts across the field. You should get well in excess of 7 volts without load at anything about a fast idle. Nev

[Phil B]

I’m at a loss. I did exactly as you have described and still get no output.

Has anyone a definitive picture of how it should look in case I just have it wrong?

[alan.moore]

Not wishing to confuse you but it is the F terminal you need to flash not D. Have a read through this post before you get any deeper into it

http://forum.arielownersmcc.com/viewt ... ?f=8&t=189

Cheers
Alan

[Phil B]

I wondered, as it was the F I originally flased but did D as F was not successful.
Just a photo so I’m sure it’s wired right would be great, or a confirmation on my pic. It’s driving me nuts!

[nevhunter]

It doesn't matter which one you flash. (D or F) You are only putting in a small amount of residual magnetism to start the process off if the machine has sat or the generator has just been dismantled. If you motor it you don't need to flash it but it's always better to just do it to be sure, if there's no output. Check for a brush hung up or a discontinuity/short in the field circuit. It's easy to remove and work on the bench. Some generators have one brush which must be the earth so you can't swap them around . Check for this situation. Lift the brushes and see if either brush holder is earthed. You might have to reverse which brush goes to D. Nev

[alan.moore]

I wondered, as it was the F I originally flased but did D as F was not successful.
Just a photo so I’m sure it’s wired right would be great, or a confirmation on my pic. It’s driving me nuts!

Looking at your photo you have it wired up correctly. BUT the two wires from the field coil (the ones that come through the backplate) can inadvertently be transposed. If they are it changes the dynamos direction of rotation and it will not charge when you run it up with the engine.

I would remove the dynamo and follow the instructions in John Nash's post to make sure it motors in the correct direction

Cheers
Alan

[Keith.owen]

Hi,
Looking at your photo
http://forum.arielownersmcc.com/downl ... mode=viewo

Compared to my dynamo it looks like your D and F connections are swapped.

If I look at the dynamo with the terminal plate in place, the F terminal is on the left and the D on the right.

Now, it doesn't matter if they are swapped as long a you have the field wired to the F terminal on the regulator and the Dynamo brush to to the D on the regulator.

I might be seeing your photo incorrectly, but do just check. I am not trying to teach granny to suck eggs, but it is worth a check however obvious it might seem!

Keith

[Phil B]

Thanks all. I’ll not get to play with it until tomorrow but will check all as advised and update.

[bill.bottrill]

Hi,
We've finished travelling for a bit,so i thought I would measure the resistor in the mcr2 cutout box you wanted awhile back.I have two of these boxes and when I first started up the square one wouldn't charge, so I just fitted the second box and it seemed ok.Well I used the duff box to check the resistor,and it read 50 ohms,however as the contacts should have shorted out the resistor at rest it should have read zero. no amount of pressure on the contacts would make them touch only a screwdriver blade across them would do it,so it looks like I have found the problem with the box,and the resistor is 50 ohms.