Class 89 Armature Converter Testing

The 11th March represented a milestone in the preservation history of 89001 with its’ Armature Converters being energised to test that they were operating correctly. Testing the Armature Converters without a 25kV supply and no traction motors to load the converters has required several months of preparation work. Arrangements were made to permit the injection of 240V AC into individual bridges on the Armature Converters, the bridge DC outputs were loaded by connecting them to the Load Bank (which is usually testing Diesel Electric Locomotives) at HNRC Barrow Hill. Control of the Armature Converters was via the 89’s microcontroller, with a hand-held control device being used instead of the locomotive’s master controller.

The testing proved successful with the Microcontroller and of the devices in both Armature Converters operating correctly.

Our thanks to Bralesford Engineering Services and HNRC for their assistance with this work.

Picture (clockwise from left); ACLG Volunteers installing power connection on to Armature Converter #2, Installation above Armature Converter #1, Hand-held control device connected to Microcontroller, Microprocessor Thyristor Firing Card sending signal Armature Converter #1 and DC current being recorded flowing to the Load Bank resistors.