Lotus Elan

Dynators + dynamo charging rpm's

PostPost by: jmp » Mon Feb 20, 2012 1:40 pm

Started to put a few miles on the elan but if swmbo'd is going to use it regularly it will have to have an alternator. I'm tending towards a dynator but shying away with the expense. The cheapest I can find at present is still well into the ?300.00 plus range. Is there a recommended supplier at a good price that people are aware off.

What sort of tickover speed are owners with dynamo's running at?
    I have a new dynamo on and at 1,000rpm it is still not charging on tickover.
    Thanks,

    John
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    PostPost by: ardee_selby » Mon Feb 20, 2012 2:06 pm

    jmp wrote: I have a new dynamo on and at 1,000rpm it is still not charging on tickover.
    Thanks, John


    Dynamo Data.jpg
    Dynamo Data.jpg (31.96 KiB) Viewed 721 times


    This is the data from early Elan specs. (Guess it should be read in conjunction with regulator settings...but they are adjusted/set when running @ 3000rpm)

    Maybe someone with more electrickery up their sleeves can help interpret further.

    Richard
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    PostPost by: billwill » Wed Feb 22, 2012 3:57 am

    Elsewhere on the forum you will see mention that an alternator should have a smaller pulley on it so that it spins faster than a dynamo.
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    PostPost by: Galwaylotus » Wed Feb 22, 2012 8:56 am

    ardee_selby wrote:
    jmp wrote: I have a new dynamo on and at 1,000rpm it is still not charging on tickover.
    Thanks, John


    Dynamo Data.jpg


    This is the data from early Elan specs. (Guess it should be read in conjunction with regulator settings...but they are adjusted/set when running @ 3000rpm)

    Maybe someone with more electrickery up their sleeves can help interpret further.

    Richard

    Just a note. The dynamo (or alternator) specs usually refer to the charger (dyna or alt) rpm rather than the engine rpm. The ratio of crankshaft pulley pitch diameter to alternator pulley pitch diameter needs to be applied to determine where the cut-in and maximum allowable engine speeds occur. Example: If the crank pulley diameter is 1.3 times the alternator pulley diameter, then at an engine speed of 1000 rpm, the alternator will be turning at 1300 rpm. It's also important to ensure that the charge warning lamp is still in the circuit as it needs that resistance to initiate the charging.
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    PostPost by: jmp » Thu Feb 23, 2012 9:16 pm

    Thanks for the replys everyone. I'll carry out some research and seek further advice once I've done so.

    John
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    PostPost by: quaybook » Sun Feb 26, 2012 5:44 pm

    Hi John

    I fitted one of Powerlite's Dynalite alternators last year. Expensive yes but an easy fit, no need to change fixing brackets or anything like that, and it leaves the under bonnet looking as it should. My car is positive earth as well and Powerlite are the only people I could find who do a positive earth alternator. Although the installation instructions said use the pulley off the existing dynamo I thought an alternator should be able to run at higher revs, so I checked with Powerlite and they agreed that it would be better to fit a smaller pulley. I therefore bought a standard alternator pulley from Matty and fitted that. Although expensive it is a great installation, all my charging worries are over (perhaps I'd better just cross a finger or two :wink: ), thoroughly recommended.

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