Mk1 ignition relay control unit for 11 AC alternator

[sunnystag]

Can anyone tell me what exactly the "ign relay control unit " does? the one at the top of the turret on a MK1. There is a separate regulator unit lower down, so what function is this other control unit?
Will be swapping out for a modern alternator.
Cheers

[Motorcycle mad]

Hi
A basic answer to your question is, it switches your alternator and regulator on when the engine starts.

What happens is that when you turn your ignition on, a supply is fed to the alternator rotor via the ignition warning lamp, this is enough to create a small magnetic field in the rotor, which when rotating starts the build up of charge from the alternator, this charge is taken via the AL terminal on the alternator to the 16RA relay switching that on, and sending full battery voltage (12 volts) to the rotor, and the regulator and starting the charging cycle.

Without the 16RA relay the 11AC alternator rotor would be fed with 12volts all the time, the rotor would be taking about 3-4 amps, should the ignition have been left on without the engine running this may cause the rotor winding to over heat, and also discharge the battery, if left on for a long period of time. Mind you other manufacturers did use that method, I suppose Triumph wanted to be that bit different to the others, and of course this system was soon replaced with the ACR type alternator which used a different set altogether, and being more compact.

To change to the ACR type alternator is not to much of a problem, you wont need the 16 RA relay, or the 4TR regulator and obviously the wiring will need modifying a bit, if you do make the change make sure you solder all your connections and insulate well.

Ken

[sunnystag]

Hi Ken
Many Many thanks for the reply
Just what i needed