Hi all, just got my sports running, four years in the making. I have a C35M dynamo with a CFR2 cut out and a SM5 switch panel.
So far I can't get any charge from the dynamo, not sure if it wired correctly, Pos from the dynamo to the D on the cut out and F from the dynamo to F on the cut out. D on the cut out to D on the switch panel and F on the cut out to SH on the switch panel.
I have done all the tests from the Cornwall A7 clubs website, everything is as it should be except I can't light the bulb when connected between the F wire and earth.

I would post a picture of the car if someone can help me, this forum mentions photo bucket, do I need to open an acc to post a photo?

Thanks Colin.

Location: Drouin, Victoria Australia

Colin,the brushes may sticking try freeing them.
KEEP GETTING SPAM WHEN I TRY TO REPLY,GETTING A BIT MIFFED!!!!!!

Location: Piddle valley, Dorchester.

The Cornwall site has several articles addressed to charging (The one Charging Refresher is particularly noteworthy for all Seven owners)

It is late and I am tired but I cannot understand the 2nd advice in the Cornwall Charging Fault Finder site, re external field circuit. I presume this is the test which has you stumped. The only connection to the battery is thru the tiny ignition bulb which will not enliven a larger one and much else in parallel. Prodding the cutout shut would achieve the desired test but it must be immediately prised open (or the battery disconnected to free). Check in Summer and Winter. If I have it wrong Peter will spot it so dont rush in!

Alternatively, as the test of field continuity within the dynamo was presumably OK, disconnect the external F wire (and insulate) and link the dyn D output to the dyn F terminal directly. Should give full charge. Can go a step further and isolate the dynamo and connect a headlamp bulb from dyn output to earth. It should light brightly at low revs (and burn out at high!).

The dynamo may be need magnetising, or be of reversed polarity, but that is another story all covered recently.

Bob Culver

Location: Auckland

Peter, I checked the brushes, not sticking, I also checked from the armature to the brush connection, all was good there.

Colin.

Location: Drouin, Victoria Australia

Thanks Bob, I will do the tests in the morning and let you know how it goes.

Colin.

Location: Drouin, Victoria Australia

Hi all, I think I have copied a photo of my sports, this photo was taken some weeks ago.

http://i1374.photobucket.com/albums/ag434/ccheeza/68e68d61a3e09ef40dc8ccfe0b2e10e5_zps477e7790.jpg

Colin.

Location: Drouin, Victoria Australia

Location: Drouin, Victoria Australia

Colin,

I always connect the main charge terminal (D) directly to the field (F) terminal with the 1920's Lucas/CAV DEL dynamo, as Bob suggests, so the system is always on full charge.

"as the test of field continuity within the dynamo was presumably OK, disconnect the external F wire (and insulate) and link the dyn D output to the dyn F terminal directly. Should give full charge. Can go a step further and isolate the dynamo and connect a headlamp bulb from dyn output to earth."

By the look of the 35M dynamo this should also work, leaving out the connection from the dynamo F to the F terminal on the CFR2 cutout, just connecting the dynamo D to the cutout D and then on to the D in the Lucas SM5 switch panel.

Tony.

Location: Malvern, Melbourne, Australia

The dynamo is actually a 35c must be a later model as it does not have the resister on it, I pulled it apart and everything seemed to be in order.
I will keep trying and doing suggested tests. Let you all know when I get some action.

I also checked between the copper on the armature continuity across each,hope this is correct.

Colin

Location: Drouin, Victoria Australia

Colin,if you still have the dynamo off, you could test by "motoring" it.Connect D & F. connect to battery +ve and earth body to -ve, the dynamo should now be acting as a motor if not faulty.
If ok polarise the dynamo when refitting :- Disconnect the D & F wires from the dynamo. Run a wire from the unearthed terminal on the battery and "flash" it onto the F terminal on the dynamo. By flash I mean brush it over the F terminal 2 or 3 times until a small blue spark can be seen.

Location: Piddle valley, Dorchester.

Colin,

If you are mixing different model Austin Seven dynamos, cutouts and switchboards, with different half charge resistor systems either inside the dynamo, outside a the dynamo or in the cutout, best keep with the full charge arrangement by connecting the D and F terminals at the dynamo.

Tony.

Location: Malvern, Melbourne, Australia

We are getting a little ahead of the game, but whilst Ford 8s made do with only one charge state, and whilst few Sevens now embark on long uninterrupted journeys, persistent charging at the 8 amp Winter rate is excessive, esp for batteries maintained at full charge on some modern float charger.

I have a 1960s car with fine calibrated ammeter, and charge very rapidly settles to a low rate. Even 10 secs on the starter at a few hundred amps is only about one ampere hour.

Ideal management of a battery without a regulator calls for some thought, but does contribute to life. (Guarantees exclude batteries without voltage regulators!)

The Cornwall site is generally excellent but it is a pity the few errors are not covered by footnotes. Many errors become evident to knowledgeable folk who read, compare, and ponder all, but are not easily spotted by new comers.

Bob Culver

Location: Auckland

Peter, the dynamo is back on the car, I did notice the third brush wire was connected to the pos on the dynamo, I think this May be incorrect.

Colin.

Location: Drouin, Victoria Australia

Colin, the third (adjustable) brush should be connected via the field coil to the "F" terminal,other brushes one to "D" the other to Earth.
I converted my own to two brush 12 volt and am rewarded by better starting,and lighting. The voltage control is I admit not original being electronic but it is totally reliable and always charges.
By the way love the car.

Location: Piddle valley, Dorchester.

Ok, I connected the D and F battery pos to D and earthed dynamo, around it went. Put it back on the car and nothing.

I have the D and F connected put a light onto D and earth, nothing.

I'm about to get the hammer out and give it a beating, I just can't work out what I am doing wrong.

Colin.

I do thank you all for your kind help, I have learnt a lot but I would like to see some movement on the amp meter.

Location: Drouin, Victoria Australia

I know you said the brushes are working, but a problem I had was that the springs just caught the top edge of the brush and held it just enough to stop proper contact to the armature, after I had reshaped the springs so they acted on the top of the brushes, all was well.

For those who are not aware, the C35 has brushes fixed in swinging arms, the C35M has brushes that slide up and down in fixed arms, basically.

Location: On the very Edge of Europe....West of Jelbert, Brian, Alastair, Bob and everybody else..

A real head scratcher Colin, with regard to your observation of "nothing" are you using a multimeter or just the cars ammeter? a very low output may not show on the dashboard but could be an indication of insulation breakdown in the field coils or commutator.

Location: Piddle valley, Dorchester.

Peter,I am using the ammeter on the car, I also presumed that the globe on the test light should also light up?

Colin

Location: Drouin, Victoria Australia

Colin,

Is it possible that you have the third brush set too 'low' - moving it in the direction of rotation will increase the output of the dynamo.

I would have thought that if you got it to motor this shouldn't be a problem but I don't know what else to suggest.

Tony.

Location: Malvern, Melbourne, Australia

Had a problem with the charging on our 10/4 Austin, went through every thing and found several things wrong/incorrect. This is a 1934 3 brush 12v set up so, make sure that what should be 12v is. Then check connections, found F2 to F1 etc, put that right. Still no charge.
Next dismantle the dynamo and clean/ inspect, found one of the small insulating bobbins - it insulates the spring from the 3 rd brush - was broken, make a new one, reassemble every thing, adjust the third brush to give just under 7 amps and 13.2 v, now happy,--------for now. (Why 7 amps? That's the best we could get !)
Morel ; Check every thing.

Joe
Suffolk

Location: Suffolk

I would advise spending a few dollars on a multi meter so that accurate voltage and resistance readings can be taken. you mention the test light "globe" from which I think you mean bulb.This may be 12 volt so may not illuminate.
This site shows the field coil test and reistance values,worth checking to rule out any faults... www.dynamoregulatorconversions.com/field-coil-testing-and-winding.php
Keep going, the problem will show up eventually. I often find leaving it for a couple of days clears the mind and the element of surprise catches the problem out.

Location: Piddle valley, Dorchester.