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Most Online1,063 Jun 14th, 2026
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Joined: Apr 2017
Posts: 1,799 Likes: 4
Talk Morgan Enthusiast
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Talk Morgan Enthusiast
Joined: Apr 2017
Posts: 1,799 Likes: 4 |
We live and learn. I said the speedo would be driven by a Hall Effect Sensor based on using the Revotec item that Dave W used. It turns out it's not Hall Effect at all but a 3 wire inductive sensor. It fooled me because I always thought Inductive sensors had 2 wires and Hall Effect had 3 wires. Turns out that Inductive can have 2 or 3 wires. Revotec confirmed it was Hall Effect but I think they were just happy to agree with me and stop me asking difficult questions. Eventually I tracked it back to Schneider Electronics who burst my bubble by telling me it was something called a PNP Inductive Sensor. Any way the nice people at VDO put me straight and told me how to wire the Speedo direct from the sensor without going via the ECU so thankfully back on track. Just goes to prove that one should not believe everything one reads on TM 
Bob
2009 Black Roadster 1999 4/4 2 litre Zetec
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Joined: Dec 2008
Posts: 22,357 Likes: 353
Roadster Guru Member of the Inner Circle
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OP
Roadster Guru Member of the Inner Circle
Joined: Dec 2008
Posts: 22,357 Likes: 353 |
It's a learning curve Bob. Always learning........
DaveW '05 Red Roadster S1 '16 Yellow (Not the only) Narrow AR GDI Plus 4
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Joined: Apr 2014
Posts: 3,550 Likes: 5
Talk Morgan Addict
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Talk Morgan Addict
Joined: Apr 2014
Posts: 3,550 Likes: 5 |
PNP just different doping to NPN transistor basically effects which way the current flows
Mark - No Longer driving Archie the Old English Sheep Mog........... 2010 Roadster 3.0 V6 (S3)
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Joined: Jul 2007
Posts: 28,892 Likes: 350
Salty Sea Dog Member of the Inner Circle
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Salty Sea Dog Member of the Inner Circle
Joined: Jul 2007
Posts: 28,892 Likes: 350 |
I thought Hall Effect was just the "posh" name for magnetic sensors?
Graham (G4FUJ)
Sold L44FOR 4/4 Giallo Fly '11 MINI Countryman Cooper D All4 '90 LR 90 SW
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Joined: Apr 2017
Posts: 1,799 Likes: 4
Talk Morgan Enthusiast
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Talk Morgan Enthusiast
Joined: Apr 2017
Posts: 1,799 Likes: 4 |
Apparently not.
There appear to be a number of different types requiring different wiring methods. Hall Effect sensors do indeed seem to work in a different way to Inductive sensors although I do not understand the electronic explanation as to how or why. Interestingly, when I installed my OMEX 600 ECU I remember the set up in the ECU had to be changed depending on whether the crank speed sensor was Hall Effect or MVR (inductive??). Luckily my crank sensor only had 2 wires and therefore was definitely MVR because Hall Effect always has 3. What I didn't know until now is that Inductive sensors can have 2 or 3 wires.
It seems I may have to learn more about electronics.
Bob
2009 Black Roadster 1999 4/4 2 litre Zetec
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Joined: Jul 2007
Posts: 28,892 Likes: 350
Salty Sea Dog Member of the Inner Circle
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Salty Sea Dog Member of the Inner Circle
Joined: Jul 2007
Posts: 28,892 Likes: 350 |
I think I've found it - Hall Effect give an analogue output, rather than a pulse output of the inductive sensor. Both though use magnetism to detect motion/position of the item being measured.
Graham (G4FUJ)
Sold L44FOR 4/4 Giallo Fly '11 MINI Countryman Cooper D All4 '90 LR 90 SW
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Joined: Apr 2017
Posts: 1,799 Likes: 4
Talk Morgan Enthusiast
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Talk Morgan Enthusiast
Joined: Apr 2017
Posts: 1,799 Likes: 4 |
I think there might be more to it than that as I read Hall Effect can output as Analogue or Digital depending on the type of circuit. However I think I will stay out of the discussion now or my rather meagre understanding will very likely embarrass me. With all the sensors and circuits we have these days it's a wonder we get time to think about good old Suck, Squeeze, Bang and Blow. 
Bob
2009 Black Roadster 1999 4/4 2 litre Zetec
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Joined: Jan 2012
Posts: 14,976 Likes: 2
Member of the Inner Circle
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Member of the Inner Circle
Joined: Jan 2012
Posts: 14,976 Likes: 2 |
With all the sensors and circuits we have these days it's a wonder we get time to think about good old Suck, Squeeze, Bang and Blow. Diesel in a Morgan?
Richard 1976 4/4 4 Seater
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Joined: Apr 2017
Posts: 1,799 Likes: 4
Talk Morgan Enthusiast
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Talk Morgan Enthusiast
Joined: Apr 2017
Posts: 1,799 Likes: 4 |
Why Diesel? Suck, Squeeze, Bang, Blow is the same for all 4 strokes no matter whether Petrol or Diesel. I guess the same holds true down under 
Bob
2009 Black Roadster 1999 4/4 2 litre Zetec
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Joined: Jul 2007
Posts: 28,892 Likes: 350
Salty Sea Dog Member of the Inner Circle
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Salty Sea Dog Member of the Inner Circle
Joined: Jul 2007
Posts: 28,892 Likes: 350 |
And for jet engines 
Graham (G4FUJ)
Sold L44FOR 4/4 Giallo Fly '11 MINI Countryman Cooper D All4 '90 LR 90 SW
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