Smart Diode Cut Out

Smart Diode Cut Out

For use with three brush dynamos, some Miller two brush dynamos which use separate regulator and cut out units and all dynamo systems which use permanent magnets for the field including the ML/Lucas Maglita units
For a number of years, Dynamo Regulators Ltd produced an excellent Smart Diode product which we fitted to many three brush dynamos and in particular, Maglitas. They have now discontinued this product so, with acknowledgement to Mike at Dynamo Regulators Ltd for the idea, The Magneto Guys now produce their own Smart Diode Cut Out - available now. 
When a dynamo is spinning it generates a voltage which will increase with revs until it is high enough to exceed the battery voltage at which time current will flow from the dynamo into the battery thereby charging the battery. When the dynamo stops spinning, it is necessary to have a device in the circuit which will prevent current flowing from the battery into the dynamo. If current did flow back into the dynamo, the battery would very quickly go flat. In a conventional two-brush dynamo, this device, known as a cut out, is normally combined with the voltage regulator. Earlier three brush dynamos do not have regulators and so the cut out used is a stand-alone device. These cut outs have taken several forms over the years including manual operation by the rider/driver, centrifugally operated mechanical switches and electro-mechanical switches amongst others - more details can be found on our Dynamo Cut Outs page. All these systems can now be replaced by this new Smart Diode Cut Out from The Magneto Guys.
The Magneto Guys’ Smart Diode Cut Out uses a surface mount semiconductor mounted on a small circuit board measuring 27 x 25mm with two flying leads approximately 150mm long. The semiconductor device used has the following features:
  • Maximum reverse voltage: 30v - ideal for 6v and 12v dynamos
  • Maximum forward current: 15A - well above the output from these early dynamo designs
  • Low average forward voltage: 26mV at 8A – that’s a very low loss of dynamo output voltage
  • Reverse leakage current: less than 1µA – that’s 0.000001 of an amp so, pretty negligible
  • Maximum operating temperature: 125° C - much higher than anything likely to be seen in use

These pictures show how easily the the Smart Diode Cut Out can be fitted inside the equipment so that, once the covers are in place, no-one knows it is there!

Wiring Instructions
This Smart Diode Cut Out is wired between the dynamo and battery. It can be used with either negative or positive earth systems as shown. All other electrical circuits (lights, horn etc.) are connected on the battery side of the Smart Diode Cut Out as on the original vehicle.
NEGATIVE EARTH SYSTEMS
Connect the red wire to the battery positive
Connect the black wire to the dynamo output
POSITIVE EARTH SYSTEMS
Connect the red wire to the dynamo output
Connect the black wire to the battery negative
HOW TO BUY: These Smart Diode Cut Outs can be purchased direct from us, the designers and manufacturers. A full invoice will be included with all purchases. Payment can be taken using PayPal by clicking on the relevant  Buy Now button below.
FOR UK SALES:
ONLY £18.00 incl. P&P!

FOR OVERSEAS SALES:

ONLY £23.00 incl. P&P!

Overseas sales always welcome!

Please check IMPORTANT NOTES FOR OVERSEAS CUSTOMERS

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