Chamberlain and Hookham Precision alternating current kWh meter 5 Amps 110 Volts 3 phase 50Hz. The voltage range can be extended by using an external reactance box and the current range using current transformers. Working, last calibrated in 1984, manufactured in Birmingham, UK. This is one of many instruments collected by Jack Davidson C Eng FIEE which I have been given by Dr Graham Winbolt. It was originally owned by Bruce Peebles Ltd.
I removed the instrument from its case as two screws were rattling around inside. These were replaced and all the others checked for tightness. I have checked that it is in working order by connecting the red terminals and the adjacent current terminals to a 110 volt supply and a resistive load.
Inside back and front views. Note the mercury thermometer above the top disk.
Connection diagram and instructions are in the lid
Latterly part of the GEC group of companies for early beginnings see: http://www.gracesguide.co.uk/