|\     /|
( \   / )
 \ (_) / 
  \   /  
   ) (   
   | |   
   \_/   
         

         
|\     /|
| )   ( |
| (___) |
|  ___  |
| (   ) |
| )   ( |
|/     \|
         

 _____ 
|_   _|
  | |  
  | |  
  | |  
  \_/  
       
       

 _______ 
(  ___  )
| (   ) |
| |   | |
| |   | |
| |   | |
| (___) |
(_______)
         

         
         
 ######  
    ##   
   ##    
  ##     
 ######  
         

IMPORTANT: enter the case-INsensitive alphabetic (no numbers) code AND WRITE SOME SHORT summary of changes (below) if you are saving changes. (not required for previewing changes). Wiki-spamming is not tolerated, will be removed, so it does NOT even show up in history. Spammers go away now.


Visit Preferences to set your user name
Summary of change:
'''VR trigger fan noise''' This page is about a strong (600W) PWM fan in a car, located in close proximity of the crank VR trigger: http://quasar.dynaweb.hu/~lezsi/vems/bmwtrigger/fannoise/vr_sensor_fan.jpg I've found the strange situation of VEMS starting fuel pumps and injectors with stopped and stand-still engine when the fan operates. Apparently the fans magnetic field is strong enough to trigger the crank VR signal- Scope shot of this noise measured on VR signal cable: http://quasar.dynaweb.hu/~lezsi/vems/bmwtrigger/fannoise/fan_noise.gif It's in the range of +-0.5V, more than enough for LM1815 triggering This is a normal scope trace of cranking the engine -without fan operating: http://quasar.dynaweb.hu/~lezsi/vems/bmwtrigger/fannoise/clean_trigger.gif I'm looking for solution of this problem. Since the signal/noise ratio is around 10/1, I've the idea to attenuate the VR signal with a series voltage divider at around 1:10 ratio.
Optional: Add document to category:
Wiki formatting: * is Bullet list ** Bullet list subentry ... '''Bold''', ---- is horizontal ruler, <code> preformatted text... </code> See wiki editing HELP for tables and other formatting tips and tricks.