Install Tachometer (Diesel)

[ali 254]

hi

Tachometer can be installed on a diesel engine?
Which parts of the engine, is connected?
How do you install it?
Thank

[Jakemate]

The Tacho on mine runs off a terminal on the alternator.
So if you wanted a similar setup to mine you'd need an alternator with a Tacho terminal and also a Tacho.

[ali 254]

The Tacho on mine runs off a terminal on the alternator.
So if you wanted a similar setup to mine you'd need an alternator with a Tacho terminal and also a Tacho.

Thanks to my friend
Indeed whether can not pitch to general alternator ?

[1664]

Indeed whether can not pitch to general alternator ?

I think that means can it be connected to a bog standard alternator or are different alternators fitted to diesels?

[Jakemate]

The diode pack in the alternator has an extra terminal connected to one phase of the stator windings, this in turn outputs an ac signal which the Tacho converts into rpm on the dial.
A normal alternator does not have this terminal

[ali 254]

Thanks Friends
For Tachometer, AC signals are needed?
AC alternator output signal can be used?(input diode)

[Jakemate]

Yes it comes off one of the stator windings before the diodes, a t25 genuine Tacho should pick up the signal

[CovKid]

Trying to get my head around this. I'm not familiar with the diesel layout but I'm assuming then that the alternator and main crank pulleys are exactly the same size for it to measure how many revolutions the engine is doing. If they were not, the tacho could be miles out surely.

[ali 254]

thanks...

[weldore]

its more to do with voltage than revolutions ralph

[ianboydsnr]

Trying to get my head around this. I'm not familiar with the diesel layout but I'm assuming then that the alternator and main crank pulleys are exactly the same size for it to measure how many revolutions the engine is doing. If they were not, the tacho could be miles out surely.

Well as it's a 3 phase alternator, then, every third peak of voltage is a revolution