Series 3 Testing voltage regulator?

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Webley1991

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In the temperature gauge thread I posted over the weekend, it was mentioned that the voltage regulator could be faulty. The vehicle is a Series 3 diesel with an alternator fitted.

How do you test this component? From what I have read it should have an output of 10v.

I have also read about digital replacement regulators. What are the pros/cons of fitting a digital reg?

Thanks for any replies.
 
You cant really test it, it is a bi-metallic strip that opens and closes contacts and "averages" 10v so if you put a gauge on it all you get is on, off, on off etc. The gauges are designed to be very slow so it all works (ish). An electronic reg will actually produce 10v.
 
You can test it with an analogue gauge but modern digital meters will not be able to give stable reading.
Best solution is to replace with an electronic version which will give out a constant 10V.
The reason for the regulator is your alternator voltage output varies with load and RPM so gauges vary with the voltage changes.
 
Thanks for the reply.

I notice that electronic regulator only has two terminals. One for 12v in and one for 10v out. The original type has more terminals. Does the wiring behind the dash require modification to fit the new type?
 
the original voltage stabiliser can have two terminal post with two connection points on each looking at electronic one has two connection points green to 12volt terminal light green to 10volt terminal
if the terminals are as shown you may have to change the connection for the light green from female to male tab or a modified piggy back tab with the crimp part removed and would suggest you use a shroud/sleeve or heat shrink tab on the replacement and heat shrink on the original as they will be floating around unlike the original ,there are types around that use the same case design so are plug and play before you do check https://www.minimania.com/Voltage_Stabilizer
http://www.britishv8.org/Articles/MGB-Voltage-Stabilizer.htm
SIII_ROM_Part_7-30 - Copy - Copy.png
 
The item I posted needs to be fastened to back of speedo as the tab is earth and also heat sink.[Will not work just floating around]
Just make up a link from the output side that goes to the inputs of the two gauges
 
Thanks for the replies.

I was mistaken about the terminals. The photos I have seen of the original type show two terminals that end with two spade connectors each.

I had an old needle type multimeter which I connected between the wiring loom connector for the sender and earth. The needle sat at 12v and dipped to 8 or 9v every second or so. This was with the engine not running. I should probably have tried the test with the engine running.

The gauge needles do not wobble when the engine is running.
 
can't beat the analogue multi meters still got my Avo MK8 ,it also has the option to zero the scale only down side is the batteries it requires the digital ones i own the reads are up and down should put a strobe display warning on them
and of course the obligatory yearly calibration certification ,and you still need prove them on a voltage source for peace of mind ,glad your gauges are working ok
 
Yes the old style voltage regulator lowers the voltage by switching it off and on to get a mean average of 10V , that's why modern digital meter will not read the output whereas your old analogue meter can.
 
Hi....There is an approach to seat test a controller. It requires a variable voltage power supply, voltmeter, and a 50 Ohm resistor. The resistor serves to restrict current in the field association for test purposes. I utilize 0 to 30V stock, with a 0 to 3A current breaking point, it has underlying voltmeter an ampmeter. The controller is fueled from the inventory, associate the controller case to the - of force supply, the (I) terminal of the controller to the + of the force supply. Likewise interface one lead the resistor to the +, and the other lead to the (F) terminal. Interface the voltmeter + to the (F) terminal and the - to ground. Start the powersupply at 12V, the voltage, at the field ought to be under 1.5 Volts, increment the force supply voltage to around 13.8V, the field terminal voltage will rise quickly, and follow the inventory. Try not to go higher than 15V.

quick-turn pcb assembly services
 
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