Alternator outputs - Hitachi alternator

[freedomlives]

Hi,

On my alternator there is a screw terminal labelled "bat" -- obvious what that's for, and then a two pin connector, with the flat blades arranged like a T and labelled R and L.

Just wondering what those outputs mean. I'm guessing that neither of them would allow for driving a tachometer.

And, given those two outputs, would one of them be good for driving a 12V hour meter, so that it measures just when the engine is actually running, and not when I forget to turn the key off?

Thanks.

 

[Dave M7040]

Hi,

On my alternator there is a screw terminal labelled "bat" -- obvious what that's for, and then a two pin connector, with the flat blades arranged like a T and labelled R and L.

Just wondering what those outputs mean. I'm guessing that neither of them would allow for driving a tachometer.

And, given those two outputs, would one of them be good for driving a 12V hour meter, so that it measures just when the engine is actually running, and not when I forget to turn the key off?

Thanks.

If you want a tach for a diesel that is simple to install and reasonably priced, Tiny Tac now makes a diesel model.

It uses a sensor against the one fuel injection line and sense pulses. You tell it how many cylinders you have so it can calculate rpm from the pulses it sees.

Diesel Tiny-Tach | Design Technology, Inc., Home of Tiny-Tach

Those two terminals on your alternator are likely to operate a warning light if it is not charging and to turn on the alternator.

Dave M7040

 

[greggyy]

Check for a drive from the pump, or fix factory tach

The alternator has provision so it will excite and start charging, not for anything else.

 

[freedomlives]

Thanks.
There is a mechanical cable to drive the factory tach that I'm missing, which leads me to believe its broken. I guess looking for a replacement is the best idea

 

[Dave M7040]

Thanks.
There is a mechanical cable to drive the factory tach that I'm missing, which leads me to believe its broken. I guess looking for a replacement is the best idea

I know you are not living in North America but perhaps this info will get you looking for a cable in a place you would not normally think of.

There are businesses step up to restore tachs, speedometers, other instruments from old cars, trucks and motorcycles. They have to be dealing in their cables and drives so could make what you need.

However, it is likely the tach failed and was making noise and the previous owner removed the drive.

Dave M7040

 

[freedomlives]

There are some odd scratch marks and burned looking ends of the needles that makes me think it was damaged, though I don't get how. I should take it apart. All its doing now is filling that hole, only the oil and alternator lamps work.

 

[Dave M7040]

What is useful, from the face of the instrument even though not working , is the rpm the tractor engine should be run to provide 540 rpm at the rear pto.

Also, what road speed you would be traveling in kph in top gear at certain engine rpm's.

The heat of the sun could damage the thin ends of the needle(s)

Dave M7040

 

[greggyy]

Thanks.
There is a mechanical cable to drive the factory tach that I'm missing, which leads me to believe its broken. I guess looking for a replacement is the best idea

I would do that, but first, pull the gauge out and use something to turn it to make sure it works, over here there are people who specialise in fixing instruments, you would have the same.....if it is not working.

Or that other tach would probably be a cheaper option, we do not have them here that I know of....

PS,,,hr meters are often broken, and on tractors I look at they always say it was working last week...mmmm....right.

 

[greggyy]

There are some odd scratch marks and burned looking ends of the needles that makes me think it was damaged, though I don't get how. I should take it apart. All its doing now is filling that hole, only the oil and alternator lamps work.View attachment 600830

Looks ok too me,,,,,personally I do not care too much about tach, but working engine hrs is useful for servicing and if selling,,,,