Arrow 6v charging system

[White.John.A]

Hi
My bike is not charging the battery. I have checked the output from the alternator. I get an output of 20Vac from each terminal. The output from the rectifier is 6.5Vdc. As there are 3 wires from the alternator and only 2 on the rectifier, where does the 3rd wire go? Is the output from the alternator sufficient? Is the rectifier faulty. If I buy a new rectifier would a change in type be recommended? The regulator is a solid state one. The alternator is not very old purchased from Drags. I have turned on the lights and revved the engine to see if it tries to charge the battery. There is very little increase on the ampmeter and the lights brightness remains the same.
Any help appreciated.

[will_curry]

The third wire goes to the light switch and increases the output of the alternator when
the headlight is turned on.

The voltage you measure should be between pairs of alternator wires and not between
an alternator wire and the earth.

If the bike still has the original rectifier it will be well worth replacing with a modern unit.
There is no voltage regulation at all in the original circuit and battery trouble wasn't
unusual.

Is this lack of charge a new problem or has the charging never worked?

[White.John.A]

ello Will,
Thank you for your help.
The tests this morning on the alternator wiring were
GB to GY =1.0 Vac rising to 2.3 Vac
GY to WG = 20 Vac rising to 50 Vac
GB to WG = 21 Vac rising to 50+ Vac.
My wiring diagram shows the GY wire going to the head light switch. Which I have connected. This does not seem to make any difference when the head light is turned on.
Should all phases of the alternator give the same output? In which case the alternator must be faulty.
The output from the alternator is AC. Should the wire to the head lights be DC? i.e from the rectifier
The output from the rectifier is 6.4 V. This seems to be low to me If I changed to a different type of rectifier, I'm not sure what will work with my bike. Can you suggest one.
The rectifier is relatively new. But I am still uncertain that it is working correctly.
The bike itself has a long history over many years. I bought it as a basket case, and with the help of a friend got it running. Since then it has sat around in my garage not doing anything. I decided that i would like to have it running again. It has been a long process . The short answer to your question. It has never charged since I have tried to get it going. Even with a new alternator and rectifier. My lack knowledge is not helpful.

[will_curry]

Hello John,

The output GB to GY does seem to be far too low which suggests to me that the stator
is damaged. I'd expect similar values to the other two. Can you measure the resistances
between the wire pairs and the individual wires and the body of the stator?

The wire to the light switch carries AC and when the headlight is turned on the GY wire
is connected to the regulator.

The rectifier output of 6.4v does seem low as well - I'd expect somewhere about 7v.
However, if the volts aren't going into the rectifier you won't get the volts out so the
rectifier may well be fine.

If you have to replace the stator it will be well worthwhile looking into the newer types
now available and the rectifier/regulators at work with them. The original system is
really quite primitive. I'm still some while from getting the engine running on my Arrow but
I may well be in the same boat as you.

Hope this helps.

[bh.sprint]

These values are from an article in the Cheval a few years ago, they may be of help. I found my alternator output was low on the Arrow but a stator with better magnatism increased it. Brian H.

[White.John.A]

Thank you for the article Brian. On all the articles I have read about testing alternators they have said that anything above 1.5 Ohms between the outlet wires is a fail. The articles are not specific to the Arrow of course. I have tested the outlet on my new and the old alternator with results I think are very similar to the diagram you have posted. i.e.
BG/GW = 1.2 Ohms New ; 1.1 Old
GW/GY = 0.5 Ohms New ; 0.5 Oms Old
GY/GB = 1.8 Ohms New ; 1.5 Oms Old
This leads me to think that my alternator is ok. Would you think I should look at the Rectifier as the problem? If so, have you used a particular one that you have used successfully?
My thoughts at the moment are, if the alternator falls within the manufactures design, it is a bit drastic to change it. although it may come to that.
I am still uncertain of the wiring of the alternator. I have four wiring diagrams, all different. Would you recommend that I use the wiring diagram of the hand book? GY to the ignition switch and GB to the head light switch. I have changed the head light switch and the ignition switch, and the new ones operate differently to the originals that came with the bike. Do you know what should happen when the bike is started. I have assumed that GB will give the head light more power, but what happens at the ignition switch with the GY. As you can see, lots of don't knows. Once again, any help is much appreciated.
I feel like I am chasing my tail, as every new part I buy seems to bring new problems with it. all part of the earning curve I guess.

[will_curry]

While the resistances do look OK the voltage output definitely isn't. I rather
suspect both stators are defective. Did you check to see if there was any
connection at all between the individual wires and the metal body of the
stators?

With the engine running and the lights either off or on side lights the
GB and the GW pair of coils in the alternator feed AC to the rectifier
which converts it to DC to run the side lights, ignition and keep the
battery charged.

When the headlight is switched on the GY which goes to the ignition switch
is connected to the GB wire from the lighting switch and this switches in
the other two pairs of coils to the rectifier. With this extra AC the rectifier
can provide the DC necessary to power the headlight as well.

Some photos of switches and the rectifier might make sorting out how
to connect things a little easier.

Somewhere I have copies of the Lucas service and data sheets for the
original equipment but it might take a day or two to dig them out.

[White.John.A]

Hi Will,
Thank you for your explanation,most helpful. This evening I started to check out the wire connections and using your information I will check that the light switch and ignition switch do transfer the current to the correct place. It seems to be a sensible step before changing any parts. The simple things often catch me out.

[bh.sprint]

Hello John,

I have both bikes on 12 volts because I felt the 6 volt system on the bike in the sixties was a bit marginal. The bikes have run for many years on 12 volts with no problems apart from when the battery gets old .
This means the output wires on the alternator are connected so it gives full output all the time and the Boyer Power box handles the excess when its not needed.
Wire connection green and yellow to green and black - connected together to terminal 1

green and white - '' '' '' 2

I've heard of switches with the wrong connections and wiring harnesses with wrong colours.Also seen alternators with the wrong colour wires.

I would follow the wiring in the Ariel wiring diagram but also follow what

[bh.sprint]

Sorry for the break - the message decided to send itself with no help from me.

I would follow what Will has said.

I found the rotor on my Arrow was down on magnetism, I could feel the difference compared with a better one just by pulling it off the vice. Also is the rotor the correct one for the stator, I think the latre one is bigger in diameter and has a spacer behind it but is thinner. Brian H.