problem with electrical system-T21

[MyT21]

Hi all,

Recently I have changed the shoddy wiring on my truimph..I did follow exactly its diagram..existing system is 12V.

The problem arised where the situation is normal while I am in ignition(engine running/bike moving) but when i turned "on" the light switch the engine will off & cannot start until I turned back the light sw "off".

my DC vol at rectifier terminal that connected to battery was measured,it is ~5-7V(throttle in mid-rev)

Does anyone can help me how to solve this probem...
what is the root caused?is it alternator producing under voltage?(i got ~ 7V AC at 2 out of 3 wires on the alt terminal)

[L.A.B.]

Are you certain that you have connected the alternator wires correctly?

What alternator wire colours do you have?

How exactly are they connected ?

[MyT21]

actually the wires color are same coz the previous owner had did recond,cannot recongnise what color for that 3 wires..however by rev the eng &measure, I found:
a)5~7V ac
b)5~7V
c)almost zero..

I have doubful either the output dc vol is enough to charger the battery or not..

My connection is:both a)&b) are sum together and connected to one of the rectfr terminal(for alternator) and the c) to the other terminal(for alternator)-which I confidence with it.

Or is current triggered by the a) &b) itself is not enough?
normally how many amps required to steadily charge the 12V battery?may be i can measure later..

many thks
shah

[L.A.B.]

Unfortunately the original wire colours have been changed to three of the same colour.

Each stator wire (single phase 3 wire type) has to be connected correctly for the alternator system to work properly, as they are not all the same, so that could be your problem if you have not re-connected each particular wire exactly as they were before?

I would expect about 2 Amps current and up to 14.5 Volts to be supplied from the alternator. 5-7 Volts will not charge a 12V battery

For 12V output the alternator has two of the three wires connected together, both these two wires then connect to one rectifier AC terminal, the other single wire connects to the other rectifier AC terminal, but the two connected wires must be the correct two out of the three.    

[MyT21]

thanks ..i got some idea of what you have said.

shah