bucket trucks

[Al Smith]

So you could use a tach and calibrate it for a speedo?

I suppose you could .Actually that is basically how the electronic speedo's work .They are made by EDO - Edm ,something like that .

They use an electronic proximity switch which works by the principal of a "Hall effect senser" which is basically how a gas pump works and converts the rpms to a speed ,rather than gallons /liters .Too much electronic gobbly gook info but that's how they work .

The speed [revolutions ] measurements are taken from the output shaft and the units can be calibrated . Not cheap .

 

[stehansen]

On this particular motor there was a little magnet pressed into the flywheel and a sensor that was in the bell housing. I'm assuming it was a magnet anyway.