Teach Me Voltage Regulators

[Admiral]

I need to learn about voltage regulators. I understand the basics of how they function, but after reading service manuals and watching several YouTube videos I still don’t fully grasp the subject. Hopefully someone can spell things out in plain English.

• What are common problems to look out for?
• How do you test a voltage regulator to see if it’s working properly?
• How do you adjust a voltage regulator so it sends the correct amount of juice to the battery?
• Is there any maintenance you need to do?
• What are A and B circuits?

This subject is top of mind because yesterday, my car stopped charging. I discovered the issue at the Hines Drive Cruise where I needed a jump to restart the engine. Once it was running, the electrical system (12-volt, negative ground) was not charging. Fortunately, I made it the 50 miles home on just the battery, but now I need to diagnose the charging system. Given that the generator was professionally rebuilt, I suspect the issue is in the regulator. Rather than just throwing a new regulator in and calling it a day, I'd like to actually figure out how these things work. Please learn me somethin’.

[Mart]

I'd suggest cleaning the points without disturbing anything or changing any adjustments.
Once it gets beyond that for me, I am more likely to screw it up than get it right.

Mart.

[MGG]

I took my regulator and generator to the local auto battery and electric shop to have them checked out and the regulator adjusted. I did this twice on two set-ups with good results.

[petehoovie]

Here's a pretty good video > https://www.youtube.com/watch?v=Q490UDP8r9A&t=283s

You'll like this one > https://www.youtube.com/watch?v=w7CxU0AhJ34

and this one > https://www.youtube.com/watch?v=MBHtXMTNUXA


I like this one >https://www.youtube.com/watch?v=SuruO6enMyw


These as well > https://www.youtube.com/results?sear...age+regulators

[Tim Ayers]

For a quick check while running, place the positive lead of the multimeter on the battery side post of the starter solenoid and the negative lead to ground. It will tell what the system is putting out while running.

Helps if you can have someone rev it up while testing.

[PeteVS]

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Old Henry authored an excellent thread about everything you'd want to know about the Ford charging system. I looked for it awhile back but couldn't find it. (I hate the search feature on most websites!) But, here's my take

In the regulator, there are three relays:

First is the voltage control. This relay has a contact that's held closed by a spring providing current to the field coils and a winding of fine wire that's connected to the generator output. As the voltage on the windings increases, it magnetically pulls the points open at the desired voltage. If voltage is too high or too low, the spring tension is adjusted by turning a screw or bending the arm that holds one end of the spring. To set voltage, one needs an accurate volt meter. The voltage should be checked at a fast idle and with a light load as well as a heavy load on the the generator, such as high beam headlights on as well as items like the radio, heater and other items.

Second is the current limiting relay. This works very similarly to the voltage relay but the coil is a fairly heavy wire and the entire generator output passes through it. If there's too much current passing through (which could damage the generator's armature and brushes) the coil will pull the points open reducing the current to the field coils in the generator much the same as the voltage relay does. To set this relay, one would need an accurate amp meter and a heavy adjustable resistor to provide a load.

Third is the cutout relay and I have absolutely no clue as to how that works.

[koates]

Admiral. Back in 1962 I started my 5 year Auto Electrical apprenticeship. It took me most of that time to become proficient at diagnosing, repairing and setting up all the different types of voltage regulators and generators. Regulators were the hardest item to get my head around. First you needed all of the factory specifications. Second the spare parts which at that time were available new but not now. Third the test equipment to do the job such as the variable speed motor test bench and the analog test gauges to read the settings you are tryiing to achieve. The object being to do the repair properly the first time around so that the customer went away very satisfied and did not have to return. The boss did not like come back jobs. Nearly 60 years have passed since then and most of the old auto electricians who learnt this stuff properly are dead and the current day auto electrical shops most are not too keen on working on old stuff. You can have a go at these repairs yourself if you get hold of the original FORD shop manuals and buy an analog meter test set. Not the best idea to be using digital multimeters on old generator type motor cars. An analog test set consists of a DC voltmeter reading up to about 30 volts. A DC ammeter reading up to about plus 50 amps and minus 10 amps. A heavy variable rheostat to simulate the varing battery conditions. You are not going to learn all of this in 5 minutes. Experience in knowing all the little tricks is what makes the difference here. Good luck. Regards, Kevin.

[terry]

I have tried working with the old point regulators and it is very frustrating, especially if you are bending the arm or arms to reduce the charge. I had a new regulator that was charging the battery too high. Finally I went with the modern electronic voltage regulator.I am using a Bosch regulator now and it is working great. And as I recall it wasn't much over $30. My system is also 12v neg ground 36 Ford. terry

[ford38v8]

I've never done it, but was told years ago that the accuracy of adjustment depends on it being done during expected running conditions, meaning as installed while engine is running, due to engine compartment heat. I'd expect even that to be questionable with the hood open!

[JayChicago]

I was able to do an amateur's adjustment of the regulator by bending the arm on the coil that controls charging rate. Did this on the car, trial and error.

Was charging at a little under 7 volt max. When driving at night, including idling at stop lights, battery seemed to get depleted some, slow cranking the next day. After adjustment, now will put-out 7.2-7.4 volt. Can drive all night with no sign of battery getting tired. It took some trial and error to finally get the arm bent just right.

Yes, I notice some difference on the gauge depending on under-hood temperature. When very cold on a cold autumn day will charge high, on the line at high end of green section on the gauge. Makes me worry about over charging. But as the under-hood warms, it comes back into the green. I think that's the nature of this electrical-mechanical, not electronic, system. Always going to be some variability with temperature.

[koates]

All the old electro/mechanical voltage regulators were temperature compensated by the use of bi-metal springs inside them. Therefore the regulators should only be adjusted after they are warmed up somewhat by the cars engine. The workshop manuals mention this. Regards, Kevin.

[Anteek29]

Upon arrival, my '55 Vic had an 8 volt battery installed with the regulator set up accordingly. Restoration back to stock 6 volts took some tweaking to establish the
requisite 7.2 volt output. It had been many years since I fiddled with regulators.

[rotorwrench]

The old OEM and some quality aftermarket generator control units were made with quality materials and a lot of parts still had screws securing them. The modern stuff has a lot of plastic and other low quality materials. Most things are riveted together and adjustments could be out of specs right out of the box. A person is lucky if they are at least properly adjusted.

[koates]

No new mechanical type voltage regulator out of the box can be assumed to be correctly adjusted and should be fully tested once it is fitted to the car by a person who knows exactly what they are doing. The quality of most new regulators is nothing like the original Ford, Autolite, Delco etc, etc regulators. Regards, Kevin.