The English Electric EE801 and its variants are the main electrical power generators on board diesel/electric rolling stock such as the class 08 and 09 shunters that have been in service on the UK rail network for 50 or so years. Our customer, who is a specialist rail company, sent the unit to us for an overhaul. The generator was dismantled in our workshops and our trained engineers set about assessing the electrical condition of the generator. This type of generator has 6 coils for the field windings each with 4 separate windings along with 6 interpoles. We were getting low IR readings on a number of windings. The findings were discussed with our customer and as these units are required to work for a further 10 years without maintenance, we recommended a complete field circuit enhancement. The field circuit connections were opened and each field coil and interpole was removed from the field case. Our engineers then set about a complete overhaul of the coils, the old insulation and taping was removed and the coils were re-insulated with class ‘H’ specification insulation. Each coil was VPI treated and fitted back to its pole piece. The complete field circuit was re-fitted and re-connected. Meanwhile, the armature was overhauled by cleaning and stoving untill the IR reading was satisfactory, then, skimming, undercutting, chamfering and profiling the commutator. The armature was VPI dipped and cured for protection and it was also re-balanced. The brushgear was also overhauled, the brush spring tension was checked and re-set and new leads were fitted. The generator was assembled and as this type is a single bearing unit that fits to the output of the engine, we manufactured a transportation rig to ensure the armature was secure in transport.

 Armature prior to machining