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History of Science Museum

Evershed's Bridge Megger Resistance Meter

Inventory Number 70539


Acknowledgement: © History of Science Museum, University of Oxford, inv.70539

Item type
Object
Makers
Evershed
Provenance
Presented by the Rutherford Appleton Laboratory
Dimensions
Height: 193mm Width: 365mm Depth: 190mm Weight: 10.15kg
Inventory No
70539
Accession Number
1992-26

Description

Rectangular wooden case containing a Megger resistance meter. There are hinges and a crack around the entire case, however, it does not open and appears to have copper screws holding it shut. The front of the case has three metal knobs; one that says "INDEX ADJUSTER", one that is partially broken and says "LINE", and a third which says "EARTH". On the left proper side, there is a crank, which can partly fold into the case. On the right proper side, there are two metal plates each with a pair of projecting metal knobs. One pair has "TO RESISTANCE BOX" written on top of the plate and an "R" between the knobs; the other has "TO RESISTANCE UNDER TEST" written on top of the plate and an "X" between the knobs. On top of the case, there is a leather handle with metal fasteners, one of which can detach from the case to make visible the plate and window below. There is a hinged metal plate below the leather handle that, when lifted, reveals a gauge underneath a glass window. The gauge counts Ohms and goes from 0 to 40 Megaohms. Beside the window on the top of the case, there is a metal plate with two dials, one of which says "X=R DIVIDED BY" and then the dial can point to one of three numbers, "1", "10, or "100". The second dial can point to two options, "BRIDGE" or "MEGGER".