I recently bought a 1974 850 in a sorry state.
I also recently bought from NOC spares a Podtronics Regulator. The instructions say the Podtronics will not work with a 3 phase alternator with a 9 coil stator.My alternator has 6 coils but the bike has 2 Zenners fitted which I thought was Mk3 Commando which had a larger output alternator. I cannot find any numbers on the stator, the numbers on the rotor areFR.4 [or is it ER.4?]
1] Did Mk3s have 6 coil alternators?
2] Is there any way I can tell if the alternator is Mk2 or Mk3? Do the above numbers help?
3]If this alternator is Mk2 [which I presume my bikeis] why has it two Zenners fitted?
4] The wiring to the two zenners has anEARTH CABLE trapped between the Zenner and the foot rest. Is this correct? The wiring diagram shows a cable coming from the Rectifier to the Zennerthen on to the Capacitor. In other words the cable to the Zenner and back are both made at the blade connector.
I hope this does confuse you as much as me but if any one can help that would be great.
Many thanks Roger
hi To try and answer some…
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Previously robert_wright w…
Previously robert_wright wrote:
hi
To try and answer some of your questions
1,all commandos are 12v
2,you need to look for a long number on the stator lu xxxxx this will tell what yoy have got 6 poles is single phase
3, if the alternator has been upgraded 2 zenners are used to take care of the extra capacity output these zenners have to be selected to be a matched pair or the lower voltage one will die.
4, the zenners should be earthed to the z plate and the other end connected to the output of the rectifier and the capacitor.
hope this helps
a three phase alternator has three wires comming out of it and has 9 poles on the stator
if you have three wires and 6 poles that is a 6v stator
regards
bob
Not quite right...3 and 4 above are not right. The MkIII Commando and the earlier JPN both had single phase high output SINGLE phase alternators. The twin Zener circuits they fitted where never matched, they fitted the Zemers on the AC side of the bridge, in fact the zeners were half of the bridge, in fact the black Lucas plate rectifier was not a bridge rectifier as it looks like, it was two dides (the bridge being completed by the zeners.) This made the two zeners on the Z plates NOT connected together but connected to the rectifier and alternator AC points. The inference for matched zeners was within a high output three phase kit from the late 70s/80s sold by Mistral Engineering (and A O Services).
Other wise the facts above are correct, 6 poles is single phase. 9 poles is 3 phase, there is two outputs of these medium and high.
3 wires (6 poles) would most likely be RM 19 for use 6V or 12V but it might be a high output single phase. 2 wires would most likely be an RM 21 12V but might be a high ouput (as per MKIII and JPN) 180W. These are all Lucas types (some of which you won't find new anymore).
Hope this helps
Al Osborn.
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hi
To try and answer some of your questions
1,all commandos are 12v
2,you need to look for a long number on the stator lu xxxxx this will tell what yoy have got 6 poles is single phase
3, if the alternator has been upgraded 2 zenners are used to take care of the extra capacity output these zenners have to be selected to be a matched pair or the lower voltage one will die.
4, the zenners should be earthed to the z plate and the other end connected to the output of the rectifier and the capacitor.
hope this helps
a three phase alternator has three wires comming out of it and has 9 poles on the stator
if you have three wires and 6 poles that is a 6v stator
regards
bob