Go Back   The Ford Barn > General Discussion > Late V8 (1954+)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 04-11-2021, 08:45 PM   #1
ahshoe
Senior Member
 
Join Date: May 2010
Location: Eastern Iowa
Posts: 350
Default Voltmeter with a generator

I am just finishing a project. It has a brand new generator and regulator (polarized). I just installed an under dash voltmeter. Starting the vehicle up and idling it has about 12.5 volts.About the same with more RPM's.... I am used to (other projects) that have a bigger output "alternators" usually showing about 14 volts. Is it normal for a generator system to only put out just over 12 volts to a voltmeter guage?
ahshoe is offline   Reply With Quote
Old 04-11-2021, 09:37 PM   #2
dmsfrr
Senior Member
 
dmsfrr's Avatar
 
Join Date: Aug 2012
Location: Abq, NM
Posts: 3,598
Default Re: Voltmeter with a generator

It depends on how sensitive the new under dash meter is.
With a hand-held volt meter measure the battery voltage when the engine isn't running.
Then measure it with the engine at about 1200 rpm, the voltage should be maybe 1.5 volts higher.
dmsfrr is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 04-12-2021, 03:09 AM   #3
KULTULZ
Senior Member
 
KULTULZ's Avatar
 
Join Date: Aug 2012
Location: IN A 'GALAXIE' FAR FAR AWAY
Posts: 6,413
Post Re: Voltmeter with a generator

Do you have a FORD SHOP MANUAL for the application?

Do you know the GEN AMP output rating? Is the mechanical REGULATOR rating matched to the GEN?

Is the VOLT REG adjustable? A GEN will not cut-in until about 1000-1200 RPM. There is a full DIAGNOSTIC ROUTINE in the manual and how to adjust the REG, if is adjustable.
Attached Images
File Type: jpg ELECT - GENERATOR SYSTEMS - 1958 SM.jpg (57.8 KB, 21 views)
__________________
*****

- DISCLAIMER -

The above posted information is in my opinion only (IMO) and may contain copy and paste material(s).

In addition, any above tech information is supplied in good faith. No responsibility implied or otherwise can be accepted for the way others use or interpret provided data.

Your experience(s), opinion(s) and mileage may vary.

DIAGNOSED CDO - (OCD In Correct Alphabetical Order)
KULTULZ is offline   Reply With Quote
Old 04-12-2021, 07:51 AM   #4
robib
Member
 
Join Date: Mar 2013
Location: Canton, Ct
Posts: 36
Default Re: Voltmeter with a generator

When checking a generator, make sure the generator is up to "operating" temperature. It can make a difference.
robib is offline   Reply With Quote
Old 04-12-2021, 08:02 PM   #5
paul2748
Senior Member
 
paul2748's Avatar
 
Join Date: May 2010
Location: Midland Park, NJ
Posts: 3,965
Default Re: Voltmeter with a generator

At fast idle (with a generator) it should be between 13.5 and 14.3 volts. A little over wouldn't hurt.
__________________
48 Ford Conv
56 Tbird
54 Ford Victoria
paul2748 is offline   Reply With Quote
Old 04-17-2021, 09:28 PM   #6
ahshoe
Senior Member
 
Join Date: May 2010
Location: Eastern Iowa
Posts: 350
Default Re: Voltmeter with a generator

Sponsored Links (Register now to hide all advertisements)
Checked it out yesterday and with the engine warm at about 1200 to 1500 RPM, I have just 12 volts at the voltmeter guage.
ahshoe is offline   Reply With Quote
Old 04-18-2021, 09:55 AM   #7
rotorwrench
Senior Member
 
rotorwrench's Avatar
 
Join Date: Jun 2010
Location: San Antonio, Texas
Posts: 16,367
Default Re: Voltmeter with a generator

If you are comfortable that your voltage readings are correct then you have a charging problem. A 12-volt regulator has to have a voltage output higher than the battery voltage in order for the battery to start accepting a good charge rate. Older voltage regulators can be adjusted but it takes some good test equipment to set voltage and check the current limiter. A shop that specializes in auto electric components should have the equipment to do that.

Modern replacement regulators leave a lot to be desired in quality.

All a voltage meter will ever tell you is that the system is generating a specific voltage. An ammeter indicates charge, discharge, and approximate amount of current draw from the load.

Last edited by rotorwrench; 04-18-2021 at 10:00 AM.
rotorwrench is offline   Reply With Quote
Old 04-18-2021, 02:19 PM   #8
dmsfrr
Senior Member
 
dmsfrr's Avatar
 
Join Date: Aug 2012
Location: Abq, NM
Posts: 3,598
Default Re: Voltmeter with a generator

Quote:
Originally Posted by ahshoe View Post
I am just finishing a project. It has a brand new generator and regulator (polarized). ---
What procedure did you use to polarize the generator?

I take the Field wire loose from the regulator and quickly brush the end of it across the Battery terminal of the regulator, then re-connect the Field wire.
So you're Not applying battery power to the Field terminal of the Regulator, only to the Field wire that leads to the Generator.
Attached Images
File Type: jpg Generator voltage regulator wiring, yellow, copy.jpg (37.4 KB, 16 views)
dmsfrr is offline   Reply With Quote
Old 04-19-2021, 08:08 AM   #9
ahshoe
Senior Member
 
Join Date: May 2010
Location: Eastern Iowa
Posts: 350
Default Re: Voltmeter with a generator

Did exactly as above to polarize the regulator. I know that because before that the factory GEN light stayed on when I started it in the shop and is OFF now after I polarized it.
ahshoe is offline   Reply With Quote
Old 04-19-2021, 09:51 AM   #10
dmsfrr
Senior Member
 
dmsfrr's Avatar
 
Join Date: Aug 2012
Location: Abq, NM
Posts: 3,598
Default Re: Voltmeter with a generator

Having the Gen light working is a good sign but if additional voltage isn't showing up at the battery terminals with the engine running there is a problem.

I'd start checking things by disconnecting a battery cable and removing the cover of the voltage regulator to see if the relay/switch contacts need cleaning. Emery paper or a small fine 'points' file may fix it.
.

Last edited by dmsfrr; 04-19-2021 at 11:29 AM.
dmsfrr is offline   Reply With Quote
Old 04-19-2021, 10:56 AM   #11
rotorwrench
Senior Member
 
rotorwrench's Avatar
 
Join Date: Jun 2010
Location: San Antonio, Texas
Posts: 16,367
Default Re: Voltmeter with a generator

The generator light function is switched inside the generator control unit or voltage regulator (VR). When the generator starts generating current there is a switch function in the current limiter pole circuit that opens the ground path for the generator light and the light goes out so at least it's showing some function. If voltage is low then the voltage regulator pole is not properly adjusted to a high enough voltage for operation.

Make sure you have good connections with the generator to VR and battery to buss/frame. Grounding of the generator to the frame and in most cases, the voltage regulator to the body have to be good. When there is no ground wire between the generator and regulator then this ground has to come from other sources. This also includes grounds from the engine/frame to the body. If all are good then either try a different regulator or find someone who can properly adjust it.
rotorwrench is offline   Reply With Quote
Old 04-19-2021, 11:40 AM   #12
KULTULZ
Senior Member
 
KULTULZ's Avatar
 
Join Date: Aug 2012
Location: IN A 'GALAXIE' FAR FAR AWAY
Posts: 6,413
Question Re: Voltmeter with a generator

Repeat of POST #3 -

Quote:
Originally Posted by KULTULZ View Post

Do you have a FORD SHOP MANUAL for the application?

Do you know the GEN AMP output rating? Is the mechanical REGULATOR rating matched to the GEN?

Is the VOLT REG adjustable? A GEN will not cut-in until about 1000-1200 RPM.

There is a full DIAGNOSTIC ROUTINE in the manual and how to adjust the REG, if is adjustable.
__________________
*****

- DISCLAIMER -

The above posted information is in my opinion only (IMO) and may contain copy and paste material(s).

In addition, any above tech information is supplied in good faith. No responsibility implied or otherwise can be accepted for the way others use or interpret provided data.

Your experience(s), opinion(s) and mileage may vary.

DIAGNOSED CDO - (OCD In Correct Alphabetical Order)
KULTULZ is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 12:29 PM.