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Instructions to follow when Fitting your converted Dynamo and/or Regulator 


Every conversion comes with detailed instructions tailored to your particular conversion but below are all the instructions that you will ever need. You should read and understand them as they are here to make the job of installation easy and trouble free for you. 

So, you have your converted regulator and/or dynamo in front of you and it's ready to fit. You should look at it like this - 

I've done the complicated and hard work for you so all you need to do is get the installation right and all will be well.  You're going to undertake a job you've probably never done before so first and foremost 


All our conversions/regulators are load tested on the test bench before dispatch so are working perfectly when you get them. 

Check your vehicles wiring before fitting. Non existent earths and bad wiring are the most common cause of charging problems in an old vehicle next to a faulty dynamo or regulator unit. 

A bad or non existent earth can damage an electronic regulator!

Remember, a dynamo and regulator are only as good as the wiring that connects them.

The most common causes of my conversions not working after installation is: 

1. Faulty dynamo. No output due to an internal problem or output of the wrong polarity 

(No. 1 applies where I convert ONLY the regulator - normally with a std two brush installation. If I've rebuilt your dynamo it will have a healthy output of the correct polarity and will be ready to fit)

2. Bad connections or vehicle wiring, broken wires, taped joints, dirty connections etc.

3. A bad earth between dynamo and vehicle. 

4. In the case of a 2 brush conversion (and cut out to regulator conversion) failing to disconnect fully the old charge system wiring at the back of the winter/summer/charge switch. 

The wire connected to the terminal on the converted cut out marked F2 MUST go directly to the F or F2 terminal on the dynamo. Any wire wound or ceramic field resistances that were fitted inside your cut out case were removed when it was converted. Some vintage and veteran vehicles had a field resistance fitted to the vehicles bulkhead. Its down to you to make sure that any external field resistances are removed PRIOR to connecting up. Your regulator WILL NOT work properly and DAMAGE could be done if there is any sort of resistance in the F or F2 wire. 

Field wiring is normally marked F, F1 or F2. Where a summer/winter or high/low charge switch is fitted on the vehicle all F, F1 and F2 wiring to it MUST be COMPLETELY disconnected. You can use the existing Field wires once you have disconnected them from any resistance or charge switch BUT the Field circuit MUST go direct from regulator to dynamo with no interruptions en route.

5. Poor D and/or A connections to the dynamo and/or regulator. Make sure all D and A connections are tight and sound and wired in the correct size cable.

A little time spent getting things right before and during fitting WILL save heartaches later. A wiring diagram is normally included along with fitting instructions when a conversion or rebuild is sent back to you.


Click HERE to see the wiring diagrams that show you how to connect up properly.


The dynamo's fixing to the engine is also its earth point so make sure it is properly earthed to the engine by its fixing bolts or clamp. If unsure, hide an earth strap between the dynamo and a fixing bolt.


Make sure that the engine is properly earthed to the chassis or frame. The battery is earthed to the chassis or frame, the dynamo to the engine so make sure there is an earth strap between engine and chassis. Rubber engine mounts will insulate the engine from the chassis causing bad charging and starting.


Some regulators i.e. Delco Remy and Bosch units are earthed through their fixings to the vehicle so make sure the metal at the fixing points is bright and clean.


Where a dynamo relies on a strap to hold it down and so earth it, make sure that the contacting surfaces are clean and free of paint where they touch, apply grease or battery terminal protector to discourage rusting of bright parts.


Use a multimeter set to continuity and test between the metal body and the chassis. Test also between body and engine.


Continuity test the wiring that goes to and from the regulator terminals as shown below


Lucas dynamo's and regulator boxes 

Test the wires to terminals marked F (or F2 in some cases), A, D and E.

F (or F2) on the regulator must go to F (or F2) on the dynamo.

***  Pay particular attention to the Field (F) wiring where a 2 brush conversion is involved. You MUST disconnect the old charge system wiring from the back of the summer/winter or high/low charge switch or damage WILL be done!

See my wiring diagram HERE. It's the one marked:


A on the regulator must go to the battery 

(via an ammeter)

D on the regulator must go to D on the dynamo.

E on the regulator must go to earth on the vehicles body/frame.


Delco Remy

Test the wires to terminals marked BATT, GEN and F.

BATT must go to the battery (sometimes via an ammeter)

GEN must go to the generator  (dynamo) GEN terminal

F must go to the generator F (field) terminal

(pay particular attention to the Field (F) wiring where a 2 brush conversion is involved).

The body of the regulator case forms the earth path so test that it is well earthed to the vehicle body/frame.


Bosch and other European dynamos and regulators

Test terminals marked D+61, B+30, DF or F, and E

D+61 must go to the dynamo D+61 terminal

B+30 must go to the battery positive usually via the ammeter

DF or F must go to DF or F on the dynamo

E is normally the casing of the regulator and must go to vehicle body/frame



If the dynamo earth path between it and the regulator is broken the dynamo will run unregulated. this shows up as very bright bulbs that go bright and dim dependant on revs and at high revs they will probably blow. Dim lights with a known charged battery are normally down to a bad earth, this includes the ignition warning lamp.


It is a good idea to put some battery terminal protector where an earth strap is bolted to the chassis or engine. Make sure that the metal is bright and clean or a high resistance joint will be the result.


Before fitting a converted dynamo or regulator always disconnect the battery so sparks don't fly if you should touch a spanner or screwdriver from a live terminal to earth.


Check and double check your connections BEFORE reconnecting the battery and fitting fuses.


Make sure your dynamo is polarised for the correct polarity.

Polarising is simple and can actually wake up or rejuvinate a dead or weak dynamo.

Always use a known good battery. Always trickle charge a battery off the vehicle if possible. Avoid fast or boost charge rates on some chargers. Make sure battery terminals are kept clean.


Never assume existing polarity or wiring is correct - Always check before connecting an electronic regulator.


The last thing you need to know is the sequence of wiring for the regulators output (A or B+30 or BATT) terminal.

It is of utmost importance here the vehicles wiring is as original. I have heard stories from customers that this wiring has been altered usually by a do it your-selfer re wiring the vehicle.

The wire from A or B+30 or BATT on the regulator should go to one side of the vehicles ammeter. The electrical load should also be taken from the same side of the ammeter (feed to the light switch etc) or else the ammeter will not show charge or discharge. The other side of the ammeter then goes off to the battery live terminal. In the case of most motorcycles a fuse is fitted in this wire between ammeter and battery live. Regulators that I convert for cars normally have a fuse hidden inside the regulators box.


Finally, follow the instructions that come with your conversion however electrically competent you are. They are tailored to your application even if it is a straightforward refit.

If you have any doubts as to fitting a conversion, entrust the work to a competent person or auto electrician.



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