Accession No

3322

Brief Description

moving iron, pointer multi-meter, by Crompton and Company, English, 1935-1945 (c)

Origin

England

Maker

Crompton and Company

Class

electrical

Earliest Date

1935

Latest Date

1945

Inscription Date

Material

wood; metal (iron, aluminium, other); glass; plastic (ebonite); paper

Dimensions

breadth 280mm; depth 150mm; height 302mm

Special Collection

Provenance

Transferred from Department of Engineering, University of Cambridge, Cambridge, England, 1986.

Inscription

‘Crompton
‘A.C. TEST’
METER AMPERES -
SCALE READING
NO. OF TURNS
VOLTS -
SCALE READING X
ACCORDING TO RANGE
202237
F.G.
BRITISH PATENTS
No. 233808/24
No. 247563/26’(on dial)

Description Notes

Rectangular wooden case with cast metal front, on rough wooden base; front with glazed kidney-shaped window showing silver coloured dial with mirror; non-linear scale, 10 to 100 divisions; zero adjustment screw above window; two metal screw clamps on top hold removable horseshoe iron of magnetic circuit; five coils, in two groups, surround this horseshoe and are connected to six terminals mounted on an ebonite plate at the left side of the meter; one turn of a 100-ampere AC current passing through the top magnetic loop results in a full-scale deflection of the meter; connections to the terminals allow for its use as a fire-range voltmeter; two pieces of iron pivoted around central axis in magnet gap; spring control; aluminium vane for damping; metal plate on side of case giving instructions for use; hand-written paper glued to base giving calibration (partly illegible).

Condition: good; complete.

References

Events