12v cut out - dead??

[steve davidson]

Hi,
 
I'm suspecting that the cutout on my 12v system has died.  I'm getting good volts at the Dyno (around 13.5) but the ignition light remains stubbornly on no matter what the revs.
 
I've cleaned and tightened all the earths and checked the connections to the ignition light. 
 
The current cutout looks to be a solid state (see photo attached). So my questions are;
 
1 – Is there a way I check if this type of cut out is faulty?
 
2- If it is faulty are there any suggestions on where a new unit can be procured?
 
3- As a side issue can someone tell me which is the A and which is the D terminal on my dnyamo?  I have two wires connected to the dnyomo one larger than the other.
 
4 – When people speak of cut outs and regulators are they one and the same?
 
Thanks
   

[bob46320]

That device just looks like a couple of diodes to stop the dynamo leaking back to earth (Like a motor) once the dynamo stops charging. Simple test is to remove it from the circuit, then with a battery and a bulb, make a circuit with this device in one of the wires. It should work in one direction, and not work when reversed.

[Robert Leigh]

Hi,
 
I'm suspecting that the cutout on my 12v system has died.  I'm getting good volts at the Dyno (around 13.5) but the ignition light remains stubbornly on no matter what the revs.
 
I've cleaned and tightened all the earths and checked the connections to the ignition light. 
 
The current cutout looks to be a solid state (see photo attached). So my questions are;
 
1 – Is there a way I check if this type of cut out is faulty?
 
2- If it is faulty are there any suggestions on where a new unit can be procured?
 
3- As a side issue can someone tell me which is the A and which is the D terminal on my dnyamo?  I have two wires connected to the dnyomo one larger than the other.
 
4 – When people speak of cut outs and regulators are they one and the same?
 
Thanks

Your cutout looks like just that: a solid state cutout, with two diodes in parallel. There is probably a dynamo field resistor added somewhere in the system. Have a look inside the dynamo brush cover; if there are still three brushes that would confirm my suspicion. If you have a solid state regulator there will be only two brushes in the dynamo. As for wiring the larger will normally be the D connection, taking the current through the cutout to the battery. Modifying a system from original to 12 volt usually with a regulator can be straightforward if you follow the instructions provided with equipment designed for the purpose. Where your system has already been modified and you don't have details of what has been done, you are probably best to get someone who understands such things to have a look and advise 'where to go from here'. Dynamo Regulator Conversions, near Lincoln are good but not the cheapest. The DVR2 from Dynamo Regulators Ltd is probably fine, but you must follow the instructions carefully.
Robert Leigh

[steve davidson]

That device just looks like a couple of diodes to stop the dynamo leaking back to earth (Like a motor) once the dynamo stops charging.  Simple test is to remove it from the circuit,  then with a battery and a bulb, make a circuit with this device in one of the wires.  It should work in one direction, and not work when reversed.

thanks bob

---

Hi,
 
I'm suspecting that the cutout on my 12v system has died.  I'm getting good volts at the Dyno (around 13.5) but the ignition light remains stubbornly on no matter what the revs.
 
I've cleaned and tightened all the earths and checked the connections to the ignition light. 
 
The current cutout looks to be a solid state (see photo attached). So my questions are;
 
1 – Is there a way I check if this type of cut out is faulty?
 
2- If it is faulty are there any suggestions on where a new unit can be procured?
 
3- As a side issue can someone tell me which is the A and which is the D terminal on my dnyamo?  I have two wires connected to the dnyomo one larger than the other.
 
4 – When people speak of cut outs and regulators are they one and the same?
 
Thanks

Your cutout looks like just that: a solid state cutout, with two diodes in parallel. There is probably a dynamo field resistor added somewhere in the system. Have a look inside the dynamo brush cover; if there are still three brushes that would confirm my suspicion. If you have a solid state regulator there will be only two brushes in the dynamo. As for wiring the larger will normally be the D connection, taking the current through the cutout to the battery. Modifying a system from original to 12 volt usually with a regulator can be straightforward if you follow the instructions provided with equipment designed for the purpose. Where your system has already been modified and you don't have details of what has been done, you are probably best to get someone who understands such things to have a look and advise 'where to go from here'. Dynamo Regulator Conversions, near Lincoln are good but not the cheapest. The DVR2 from Dynamo Regulators Ltd is probably fine, but you must follow the instructions carefully.
Robert Leigh

Hi Robert, thanks for the reply, will have a look and move forward from there.