Alternator question

[reeltime]

Hi People
I have a Marine Trader 40 with twin 120 hp Fords.
I have fitted new gauges in the flybridge and cant get the taco to read right as I need to find out more info a sto how many pulses it puts out so I can alter the dip switches to suit.
The Alternator is a Lucas Elektrik 540 486 00 12V 07/11 NB
I cant find any info on it .
Any help appreciated
Cheers

 

[tiltrider1]

Lucas Electric - Price of Darkness.

 

[EngNate]

What you need to do is borrow a hand-held tach and set your switches/adjustment to match.

 

[reeltime]

Hi Engnate, thanks for the suggestion, but I know my revs ,the downstairs rev works accurately, the problem being my new upstairs one hasn't been calibrated ,I have the chart on dip switches to change that comes with the gauge but need to know how many poles/pulses my alternator has . The gauges are different brands so cant copy dip switch position.
I cant find any info on my alternator and its a sealed one so cant see inside to count the poles .
Thanks Keith

 

[catalinajack]

If you do not have Geldinning engine sychronizers you can simply use the drive on the side of the engine for a pulse generator. You will get a consisent signal and accurate taxh readings. See the pic I attached. The pulse generator is the gizmo with the red cap to the right and below the on-engine fuel filters. Set your dip switches to match yhe pulses generated by whatever one you choose.

 

[Tom.B]

cant get the taco to read right

Try adding sour cream [emoji16]

 

[reeltime]

Hi , good idea ,I might go down that path ,
Only good thing about covid is I have time to catch up on these things , Cleaned and painted bilges from bow to nearly the stern stern
Cheers

 

[EngNate]

OK, you have a tach to go by, why not just play with the switches until the new one reads the same? If the reading is low, set # pulses lower, if it's high set pulses higher. It's all that needs to be done to calibrate the new unit, whatever else is an academic exercise. Nevertheless, on that road you have two options: Use a multimeter that reads Hz and check the tach output terminal with it, and divide the reading by the rpm to get your pulse setting. If you want to know the # poles, divide by the pulley ratio. Or, take the alternator apart and count the triangular shapes of the rotor core, that is the # of poles, multiply that by the pulley ratio and you have your pulses per rev. You have/can find the instructions for the lower tach(?) - determine the pulse/rev from it's switch settings - and, you'll probably find the p/r switch settings are the same, there are switches for 1,2,4,8,16... pulses per rev, allowing any value in between to be set. Have you tried setting the (pulse) switches the same?

Cheers!