Author Topic: A65 6v - 12v Alternator  (Read 1423 times)

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STAR TWIN

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Re: A65 6v - 12v Alternator
« Reply #15 on: 20 May, 2017, 14:56:23 »
With old alternators (bare and encapsulated) you need to be sure that the rotor and stator diameters match. For reasons best known to themselves, Lucas changed (reduced I think) the rotor diameter and stator inner diameter at some point in the 1970s.

JulianS

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Re: A65 6v - 12v Alternator
« Reply #16 on: 20 May, 2017, 16:05:35 »
RM13 and 15 alternators took a 70 mm diameter rotor.

These were superceded in about 1962 by the RM18 and 19, which took a 74 mm rotor with flat sides.

So the encapsulated stators would all take the 74 mm rotor with approx 8 thou rotor to stator pole clearance when fitted.


TRIGWELL

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Re: A65 6v - 12v Alternator
« Reply #17 on: 20 May, 2017, 17:41:10 »
Just returned from Kempton - feet ache ! - Really good turn out with a fantastic Classic Bike Show under the main Grandstand.
Anyway, common sense finally took over and I decided NOT to buy a new Alt. (stator & rotor (the price alone made me reconsider)).
I spoke to Paul Goff (nice man - but quite expensive) who assured me a new Reg/Rec box was a good place to start and discard old Rec and Zenor Diode, Heat sink etc.(priced at 35 - could have got one for 28 elsewhere bit his advice/knowledge was worth the extra couple of quid).
I will setup with my 'old' Alt. (Stator & Rotor), wire in the new REG/REC box and cross my fingers - if its no good then a new Stator & Rotor will be purchased.
The new REG/REC box came with easy fitting instruction along with instruction regarding the 2/3 wire issue, which I now know to be a very simple fix, i.e.  join 2 of the wires together and feed reg/rec with just 2 wires. 
Just for info Stator 82.95, Rotor 84.95, REG/REC box 34.95 = 202.85

TRIGWELL

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Re: A65 6v - 12v Alternator
« Reply #18 on: 20 May, 2017, 19:58:06 »
I now have another concern.....................please see attachment.
My concern is the output from the Alt. will be A.C. to the Rec. - from the left hand post of the REC., a wire pegs off and goes to 'post' no. 7 on the lighting switch, surely this 'current' will still be A.C.?
Anyone have an explanation ? - ray t

JulianS

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Re: A65 6v - 12v Alternator
« Reply #19 on: 20 May, 2017, 20:33:05 »
The wiring diagram is from the 1962-65 workshop manual. Essentially a 6 volt diagram with the light switch switching connecting the full output of a 3 wire alternator when headlights on.

The circuit works like this - far left of your diagram the GY goes to terminal 17 of ignition switch. With ignition on 17 connects to 18 and via cable B (black) goes to 7 on light switch.

Light switch in H position 7 connects to 6. Internal connection from 6 to 5 and connection via GY to left side of rectifier. No current passes as no connection from alternator to the GY on left side.

These AC connections to the swiches are completely isolated from the DC circuit.

I would simply disconnect the wire.

The 1966 on wiring diagrams and harness for 12 volts are much simpler and easier to follow.

I have attached a generic Lucas 12 volt wiring diagram for info.
« Last Edit: 20 May, 2017, 20:40:23 by JulianS »

TRIGWELL

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Re: A65 6v - 12v Alternator
« Reply #20 on: 20 May, 2017, 21:04:31 »
I must admit this diagram is much simpler and easier to follow, my only problem is I have bought a new 1966 wiring diagram so really need to stick to original diagram as much as possible, but for clarity & understanding I can use this - many thanks - I also agree about 'forgeting the rectifier lead to light switch' as 'all'  output from the Alt. will be going straight to the new Reg/Rec box.- ray t