BrickBoard Archives
The files contained in this listing have been automatically archived from the active forums. Because the vast majority of posts are now in one place, this archive is considered legacy. You should use the SEARCH feature OR choose your topic and select date tabs within the forum you choose.
hall effect sensor[ALL/1998] posted by Paul Mohney on
Saturday, 27 September 1997, at 7:25 p.m.
No one I know has any idea what the hall effect is or why it might be important to have it in a volvo distributor.
So I n a thousand words or a lot less: please what is a/the hall effect
or which models it is particiular to and the next time i'm at the dealer i will read a manual there, 10/q
paul in santa ana
Re: hall effect sensor[ALL/1998] posted by Abe Crombie on
Saturday, 27 September 1997, at 8:20 p.m.
The hall effect sensor as used in B21/23/230 applications 1981-1989, is used
to tell an ignition computer when the crankshaft is in a particular posi-
tion. The computer uses this for calculating how fast engine is running and
when to provide spark. The Hall effect switch is an electronic device con-
taining some type of semiconductor that is affected by magnetic field. It
outputs a ground when active that lowers a 5 volt source from the computer
to approximately 0 volts. The magnet is mounted opposite the hall switch
and a shutter wheel (basically a cup with four notches cut out on the side)
passes between the magnet and the switch to turn on and off the magnet sig-
nal. Typically the magnet turns on the hall switch at 54 degrees before top
dead center and the shutter wheel blocks the magnet at 6 degrees before top
dead center. The ign. comp. uses the interval between the last cylinder's
6 deg. BTDC point and the current cylinder's 54 deg. BTDC point as a engine
speed computation and then calculates the appropriate delay after the 54deg. BTDC before releasing the ground on the ignition coil to cause spark from
coil. The bosch systems (740,760,780) have an external coil switching tran-
sistor near the battery, this is called the power stage. The ignition com-
puter's output signal is amplified by this unit as this allows the ignition computer to stay cooler and be mounted inside the car since it doesn't
actually handle the current from the ignition coil.
I hope this explains Hall switches well enough to cure your curiosity. If
it doesn't, just ask.
Re: hall effect sensor[ALL/1998] posted by Paul Mohney on
Saturday, 27 September 1997, at 9:26 p.m.
Thank-you very much for the explanation, Your explanation, was more than adequate, and understandable,,
As I ride Volvo dinosaurs( 75 and earlier 164's) therer have been volumes upon volumes of change, , Thanks for the update
Paul in santa ana