Farm Equipment - 7060 tach

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7060 tach

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=31042
Printed Date: 09 Mar 2025 at 9:55pm
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Topic: 7060 tach

Posted By: acer
Subject: 7060 tach
Date Posted: 20 May 2011 at 8:49am

on a delco alternator with post for tach signal how much voltage should be there? is it low to high as engine speed increases? i cant seem to make my tach work i need to double check gauge itself but im reasonably sure its good and has power. is there a ohm test on gauge to confirm this, thanks

Replies:

Posted By: skipwelte
Date Posted: 20 May 2011 at 9:26am

The voltage at the tach signal is only about 3-4 volts and its AC not DC, what the tach picks up is the AC sine wave not so much the voltage. An alternator is a three phase alternating current generator, the rectifier changes the AC to DC, the tach picks up one of the AC phases and counts the sine wave fluctuations and turns that signal into a linear readout. HTH

Posted By: acer
Date Posted: 20 May 2011 at 10:45am

many thanks thats good info

Posted By: acer
Date Posted: 23 May 2011 at 9:56am

okay so i have ac voltage at alt. terminal and at tach terminal on the tach as well as power on the + terminal - is grounded as it should be. does this mean my tach is junk?

Posted By: monitordoc
Date Posted: 24 May 2011 at 10:01am

Tach may be ok. there are three terminals on the back. one is 12 volts, 2nd is ground and third is signal from alt.

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WD,D17-S4,180,D21

Posted By: acer
Date Posted: 24 May 2011 at 4:13pm

yes i have 12 volts on + terminal - terminal is grounded (ac tap ) has 3 to 6 volts ac to it the hour meter is working but no tach needle movement. i have also notice in the parts breakdown some models use a resistor and a capacitor on connections on back of the tach, is this necessary? thanks