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TR6 alternator wiring


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Hi All

I am still rewiring my TR6 (yes - still!).

I have a query. My old wiring had a thin brown wire that was cut off (no connector and not wired to anything), near the alternator.

IMG_3326-L.jpg

I told Autosparks this when I ordered my new loom (sent them the above picture) and the new loom also has a thin brown wire but it has a spade terminal on it.

It seems that the other end goes to the connector block on the inner wing.

The alternator wiring has been beefed up (as recommended by Autosparks) and I have replaced the Ammenter with a Voltmeter

So - my question is - where does this wire go?

Any help much appreciated.

Thanks

Rog

Edited by Pogo
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Thanks for the info Gents.

The diagram for the 1971 TR6 doesn't show the brown wire (but there is a brown/red one), so I think I'll leave it unconnected like it was on my original wiring. Seems odd to just have a wire unconnected.

Rog

 

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I have the same thin chopped brown wire on mine. Would be interested in knowing what it was

Tim

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I have a brown and a brown and yellow cut  and tied back. I suspect they were need for the original alternator in 1969. Maybe some form of charging control in the days when alternators were replacing generators through the industry.

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Something in the voltage control or energising of the alternator perhaps?   To do with 'machine sensed' and 'battery sensed' alternator types, according to some Lucas/Unipart blurb I have somewhere.

I guess the earlier cars had a battery sensed voltage control or energising circuit, ( the 2 plug alternator TR6 69/70 that has a 2nd  wire to the battery connected to the smaller plug ) & later cars + all replacement alternators are now machine sensed voltage control, with the single big plug with 3 terminals (1973 on)

Beyond that I can shed no more light. 

I do know that when fitting some of the Nippon Denso alternators (ex Kubota garden tractor) you need to install an ignition controlled supply to energise it. - More wires!

Peter W

PS Found on the web - No Responsibility taken for content.

"The term is generally applied to alternators, but chargers can be built with remote sensing connections as well. Machine sensed alternators sense the voltage as it appears at the terminals of the alternator. If the battery is some distance away, voltage drop may result in a battery voltage that is noticeably less than the alternator terminal voltage. If Battery isolators are added so that a single alternator can supply more than one battery, then that voltage drop should be compensated for as well. Failure to compensate for drop in a battery isolator can result in undercharging and slow recharging performance.

Battery sensed alternator (or charger) regulators have a connection for a sensing wire that can be extended to the battery positive terminal and adjust the alternator output to compensate for the various voltage drops in the positive line. In automotive installations this is satisfactory because distances are normally short and the drop in the chassis returns is minimal. In marine installations and some other installations with long wire runs in both the positive wire and the negative return wiring, even battery sensing will not compensate fully."

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16 hours ago, Pogo said:

Hi All

I am still rewiring my TR6 (yes - still!).

I have a query. My old wiring had a thin brown wire that was cut off (no connector and not wired to anything), near the alternator.

IMG_3326-L.jpg

I told Autosparks this when I ordered my new loom (sent them the above picture) and the new loom also has a thin brown wire but it has a spade terminal on it.

It seems that the other end goes to the connector block on the inner wing.

The alternator wiring has been beefed up (as recommended by Autosparks) and I have replaced the Ammenter with a Voltmeter

So - my question is - where does this wire go?

Any help much appreciated.

Thanks

Rog

PPS  If that spare wire is live, then insulate it.

Peter W

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7 minutes ago, BlueTR3A-5EKT said:

PPS  If that spare wire is live, then insulate it.

Peter W

Thanks Peter

That is my old set up. The new loom has a plastic sheathed spade terminal and I will tape it up now I know it's not required.

Rog

Edited by Pogo
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I believe it is some type of exciter or something, I think it triggers the altinator on start up.  BUT I do not know this for a fact.

i replaced my alternator on my 76 recently, the new alternator did not have a post for this wire. I was told that I could tape it up.  Instead, I took the spade of the old alternator and installed it in the same place on the replacement. The spade is not "connected" to anything as it is mounted to plastic, but  looks original. The replacement altinator is identical to the original, except with a plain back cover, I replaced this with the original Lucas embossed rear cover.

Graham

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