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What Are The Odds

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s_kilishek(at)yahoo.com
Guest

Posted: Fri Dec 29, 2006 10:22 am Post subject: What Are The Odds

Chuck:



Good question.



I'm an getting overvoltage light from the annunciator

panel, which uses one sensor to pick up buss voltage,

and getting a digital voltage readout from a separate

sensor on the EMS.  Both concur on the overvoltage.



In terms of wiring, I think the following is true:



We're getting 12 volts to the regulator and the

connection  from the regulator to the field terminal

is sound (since the alternator is charging).



The OVM-14 overvoltage device is working (alternator

cuts off when voltage goes over 15 volts).



I can't tell whether the regulator is not regulating

or is regulating at >15 volts.

George



Chuck Jensen wrote:

      

      Are you measuring the voltage with a minimum of

two different

      instruments?  In short, are you sure it is the

voltage and not the

      measuring device/indication?

      

      Chuck Jensen

      

      

      --

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nuckollsr(at)cox.net
Guest

Posted: Fri Dec 29, 2006 9:24 pm Post subject: What Are The Odds

At 10:16 AM 12/29/2006 -0800, you wrote:



 	  Quote: 	
		  



Chuck:



Good question.



I'm an getting overvoltage light from the annunciator

panel, which uses one sensor to pick up buss voltage,

and getting a digital voltage readout from a separate

sensor on the EMS.  Both concur on the overvoltage.



In terms of wiring, I think the following is true:



We're getting 12 volts to the regulator and the

connection  from the regulator to the field terminal

is sound (since the alternator is charging).


	


   "Getting 12 volts" is not especially definitive. Do

    the specific votlage measurement cited below . . .

 	  Quote: 	
		  The OVM-14 overvoltage device is working (alternator

cuts off when voltage goes over 15 volts).


	


   How does it "cut off"? The OVM-14 is supposed to trip

   the field supply breaker. If the breaker does not trip,

   the OVM-14 is not a part of this trouble-shooting

   task . . .



 	  Quote: 	
		  I can't tell whether the regulator is not regulating

or is regulating at >15 volts.


	


   Easy. Use a voltmeter to measure between the A/S terminals

   and regulator case. THIS is the point where the regulator

   believes it is seeing bus voltage. You may find that it

   it sitting happily at 14.2 volts while voltage

   drops in wiring BETWEEN the A/S terminals and the BUS

   are cause for an artificially raising of regulation set-point.



   Take one of your regulators and install some short leads

   on it as illustrated below. Install right on the back of

   the alternator and see what the bus voltage does while

   the engine is running and you vary loads by turning things

   on and off. These experiments totally bypass all other

   ship's wiring.



http://www.aeroelectric.com/Pictures/Regulators/Alternator_Test_1.jpg



http://www.aeroelectric.com/Pictures/Regulators/Ford_Test_Reg.jpg



   I think you'll find that the alternator and regulator

   are fine . . . there's some bug in installation.



   Conduct the experiments cited above and report back the

   results. We can begin to divide the probabilities-list into

   manageable partitions.



   Bob . . .

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