Conference terri::cars_uk

    Contact your local LUCAS SERVICE CENTRE, you can find them your local
    YELLOW PAGES, they should be able to point you in the right direction.
    
    

    
    Re .1
    
    I'm not sure that that'll be as easy as it sounds! :^)
    
    Perhaps this conference should be renamed EURO_CARS due to the large
    number of mainland European contributors?
    
    Mark 

    RE .1 & .2
    
    Sorry,  I'm Dutch. There is no Lucas agent overhere in Holland.
    Lucas is used mostly on UK cars, which do not appear frequently
    anymore on the continent.
    
    Yellow pages will be empty on Lucas. Still "Prince of Darkness"....
    
    Hans
    

Hi Hans,

As a very rough suggestion, try this:

Connect the white and black leads to an AC (?) supply, of 10-20 volts variable

Connect a voltmeter between the red and black leads.

Check the output voltage stamped on the alternator id plate

Check the output voltage matches this when varying the voltage supply...

Alternatively, if you think it's broken, buy a new alternator...

Scott

	.0 is about correct. All you really need to know is that if the
	red ignition light in the car glows all the time then the 
	rectifier stack is faulty.

	An exchange one is usually best.

	-John

    Thank you all so much for the well meant advises!
    
    I have dismanteled the unit yesterday and found the following:
    
    1 The AC leads(3) measure almost zero ohms, but when the alternator is
      turned, some very little AC voltage is measured on all leads.
      I conclude the AC main windings are o.k. Anyway no shortcicuit.
    
    2 The rotating part measures 4.5 ohms, which seems similar as the 
      Talbot Horizon manual advises on their alternator.
    
    3 Brushes are o.k. longer than 5 mm as Haynes manual says.
    
    4 I have dismateled the rectifier pack and all diodes 
      look good to me. (Ohms meter)
    
    5 Remaining part is the regulator.
      Out of the Haynes manual descriptions, it looks to be type 11TR.
      Now what I measured with an ohms meter.....
    
      Red - Black 	1.2 K ohms
      White - Red	Diode like connection = one way current
      Black - White	Diode
      
      Housing to: All colors: Diode
    
      About the red light:
      Bright when engine is not running
      Less bright, at 1000 rpm
      Almost noe when running at higher revs.
    
    Sofar I have cleaned everything; the brushes were not moving quite
    well. From the manual and other reactions in this notesfile, 
    it looks many persons in the automotive world don't have a deep
    knowledge of electrics and/or are affraid of electrics.
    I heard the same story from others here at DEC HQ.
    
    Cheers,
    
    Hans
    

    I need to check the alternator on my wifes Metro (Lucas type).
    
    I have a Haynes manual and a voltmeter but URGENTLY require an ammeter
    that goes from 0 - 100 AMPS !! to check the current output .
    
    CAN ANYBODY loan me one for the wekend please ?
    
    Thanks 
    
    JDB

Presumably you have a little multimeter, so here's how to make it read any range
of amps you want:

Set multimeter to measure current; if several scales, choose largest.

Measure resistance of your ammeter (ok, so you need another multimeter to do
this, but it should be easier to find than a 100A ammeter!)

If this resistnace is R, and the FSD of the ammeter is A1, then wire a resistor
of value:

    (A1 * R) / (A2 - A1)

in parallel with the ammeter to make its FSD be A2.  In your case, A2 is 100A.

Scott

PS FSD = full scale deflection; ie the highest current that is on the ammeter
scale

For completeness, here's how to make any-scale voltmeter.

If voltmeter has resistance R and FSD V1, and you want FSD voltage to be V2,
then wire a resistor in series with the voltmeter of value:

    R * (V2 - V1) / V1

Note voltmeters and ammeters are exactly the same: moving coil meters that
measure current.  It's just the resistors in parallel / series that make them
useful for measuring different current ranges, and also voltages...

Scott

    re .8
    
    You will find that the resistance for a 100A meter is very low. You may
    have problems finding one of the required value, so you may end up
    putting several in parallell. Make sure that they can take the current
    that will be flowing through them - a 0.002 Ohm resistor will dissipate
    20W at 100A ! If you have a low voltage scale on your meter (say 200mV)
    then it will be easier to put a resistor in the circuit and measure the
    voltage drop over it ( 0.002 Ohm drops 200mV at 100A).
    
    Also make sure that if any fault in your resistor network should occur
    (such as a wire coming loose) that you dont end up passing 100A through
    your meter (dont count on the protection inside the meter saving it
    with a gross overload). Usually you can do this by connecting the
    resistor in the circuit to be measured, and then connecting the meter
    to the leads of the resistor. This is another reason to use a low
    voltage scale, rather than a high current scale - you can get
    everything working and then put the meter on the circuit
    
    re .8 and .9
    
    That formula works when I2 > I1, or V2 > V1. Your accuracy will be
    limited by the accuracy of the resistors you use - you should try to
    find 1% tolerance resistors (not easy when making a high current
    meter).

    Hi John,
    
    It is very uncommon to measure such high currents in car electrics.
    My advise:  
    Dismantle the alternator and loosen the rectifier block. (write down
      how it was connected first!)
    With an ohm meter measure every diode. One way electrical traffic
    should be the fact.
    (Leads first one way: meter swings out / leeads vice versa: no
    movement of needle)
    
    If diode(s) are faulty: replace block.
    If not: measure rotating field. (should be +/- 5 ohms)
    	If this is wrong: swap alternator (either short circuit or open)
    
    If above is still o.k.: measure every static field:
    With ohm meter: almost zero ohms.
    With multimeter on DC voltage lowest scale: 
    for every field: turn the alternator: every field should indicate
    minor alternating voltage. (rotating field still is a bit magnetic)
    	If fields are o.k.: regulator might be failing part.
    
    Action than depends, what a new regulator costs, or a swap alternator.
    
    
    A general check for proper current indication might be:
    put high beam on in dark: let engine at idle low revs.
    After this, let engine run 1000 RPM or higher; lamps must give more
    light.
    
    I hope this may help.                                                 
    
    Have a grappa if it still does not work!
    
    Cheers,
    
    Hans
    
    
    

    Hans,
    
    Thanks for the tips , I will look into it this weekend (providing its 
    not to wet/cold) ..... perhaps the grappa might help there !!
    
    John