Kempton Steam Museum - The Mercury Arc Rectifiers

Kempton Steam Museum volunteer David Walker describes the history and operation of the museum’s Mercury Arc Rectifiers. Mercury Arc Rectifiers are designed to convert AC to DC. The units at Kempton Steam Museum were originally installed at the Royal Opera House in Covent Garden to drive stage winches and motors. When they became redundant, they were rescued by museum volunteers and installed at Kempton to replicate units that were once used on the site. They are still regularly used to power the museum’s heavy duty electrical equipment and can be seen operating on open days. See for more details.