Dynamo E3L and E3H Restoration

At SRM we specialise in the renovation of these particular models of LUCAS dynamos. In the 1940s the LUCAS E3H (40 Watt) unit was used extensively on a variety of British single cylinder engines later to be replaced by the more powerful LUCAS E3L (60 Watt).

The E3L dynamo was used on many British twins such as the BSA A10, TRIUMPH T100,T110 and NORTON DOMINATOR. The design of this dynamo is the same throughout the range but different drive shafts are used for different models. Each dynamo is tested on the CRYPTON MAGMASTER to help determine its condition and an estimate of the cost to renovate the unit is produced. If the dynamo was to be fully restored a new armature and field coil would be fitted together with new bearings. The outer body would be Nickel plated and the alloy ends bead blasted. New brushes would be fitted and then the dynamo would be thoroughly tested.

The testing procedure is in two parts:-

  1. Firstly the dynamo is wired for a ‘motor’ test - this runs the dynamo as a motor, the motoring speed is checked as is the polarity and rotation. This test also polarises the magnetic field in the field coil core.
  2. The dynamo is then fitted to the CRYPTON MAGMASTER or the CRYPTON ELECTRICAL TEST BENCH to be driven as if the dynamo were fitted to the engine. This test confirms the dynamo will charge when fitted to the engine and in the correct polarity for the earthing system on the bike. The dynamo is run for a minimum
    Send your dynamo to us, we will test it to ascertain its’ faults and contact you to discuss the work required (we can provide you with an estimate of costs before work begins)                                  
Code Service Price
DYNOREBUILD Strip, build and test labour for Dynamo £67.60


The work carries a 2 year guarantee

To arrange collection and delivery of everything from your electrical parts to your whole bike.

click here to arrange a collection.