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jimmymckenna
jimmymckenna
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Ragmanx Offline OP
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Ha!

I frequently type with a Yorkshire dialect, although I have no idea what that is!

My diagnosis of my problems with the charging system have left a lot to be desired. Hopefully the new stator will be the last part to be throw at it!

We will see in a about 10 days when it arrives.

Wish me luck!

SteveG

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Good luck


Now let’s all have a beer beerchug

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Well the stator and reg/rec will be new, so assuming the wiring is good, you will see some charging at some rpm. Hopefully the rotor still has reasonable magnetic strength, that will be the remaining uncertainty.
If the system voltage is at least 13V at 3000 rpm with the headlight on, I think you'll be ok.

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Ragmanx Offline OP
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OK. Thanx guys.


Will post results.

SteveG

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Hi Dave,
Originally Posted by koan58
concur with your statement:
Originally Posted by Stuart
... 'original Lucas' rated the RM21 for 10.5A @ 5,000 rpm and, as I say, the RM23 for 14.5A @ 5,000 rpm; 75% is 7.875 Amps and 10.875 Amps respectively, an extra 3A at low rpm is a bit more than "differ very slightly" on these old heaps.
You are however, placing much faith in the advertised figures.
The quote says "rated".

Triumph, BSA and Norton had enough faith to repeat the ratings (or the corresponding 120W and 180W) in their contemporary advertising (somewhere in the electric-start Commando advertising is "15A @ 6,000 rpm").

The standard Triumph workshop Manual test for an RM21 is minimum 9A AC @ 3,000 rpm with a 1-Ohm resistor between the stator wires; those more familiar with BSA and Norton workshop manuals can confirm what they used.

Originally Posted by koan58
Promotional ads from Lucas in ~1980 did suggest that the 3-phase system would solve all my issues (which it did).
High-output 3-phase was advertised from launch in summer '78 with the previously-mentioned 75% and 85% @ 2,400 rpm, presumably to indicate the superiority of 3-phase. You placed faith in the advertised figures and have positive first-hand experience.

Originally Posted by koan58
If the system voltage is at least 13V at 3000 rpm with the headlight on,
"13V" based on ...?

Regards,

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"13V" based on ...?

A 12v system is actually a 13.8v system. Over 14v is required to charge the battery


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Hi Andy,
Originally Posted by Andy Higham
A 12v system is actually a 13.8v system. Over 14v is required to charge the battery
Steve The OP's bike has a reg./rec. (the Podtronics of the thread title); if the battery is fully-charged?

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Stuart:
“"13V" based on ...?”

Nothing terribly precise, only that it is a figure a little above battery voltage, so illustrating that the generated supply is exceeding the demand of lights and ignition (I guesstimate ~8A), which even the standard alternator should do (when new) at 3000 rpm (spec’d as 9A minimum).

My full post was:
“Well the stator and reg/rec will be new, so assuming the wiring is good, you will see some charging at some rpm. Hopefully the rotor still has reasonable magnetic strength, that will be the remaining uncertainty.
If the system voltage is at least 13V at 3000 rpm with the headlight on, I think you'll be ok.”

This makes it clear that the only remaining uncertainty was the rotor magnetism (which is highly unlikely to be as good as when new) but if the parameters in my last sentence were met, then the OP should be ok.
It seemed to be clear, straightforward English to me.

I would hope that the higher output RM23 will result in rather more than 13V in that test (with its supposedly extra ~3A at those rpm), but some of that anticipated extra may be negated by some loss of rotor magnetism. Hence my suggestion to actually test it.

Regards.

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Ragmanx Offline OP
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Anxious to receive the stator on the 25th. I will install the next day. Hope the wires will be cooperative, threading thru the case.
And the rotor is still magnetic.

That will tell the story, we will see.

SteveG

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Anxious to receive the stator on the 25th. I will install the next day. Hope the wires will be cooperative, threading thru the case.
And the rotor is still magnetic.

That will tell the story, we will see.

SteveG

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Ragmanx Offline OP
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Charging problem solved!

Installed the Lucas stator. Fired first kick. Charges over 14 volts on fast rev. Perfect.

Wound up installing the 16 amp. stator, new battery, and Podtronics reg/rec

Probably didn't need the reg. The stator was the culprit. and now I have a spare reg. and that's fine.

Thank you all for the valuable input. I learned a lot!

SteveG

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