Accession No

3355

Brief Description

electrodynamometer, suspended coil AC-DC Ammeter, ranges 0 to 0.06, 0.2, and 0.6 amperes, by Siemens Brothers and Company, dec. 1890.

Origin

Maker

Siemens Brothers and Company

Class

electrical

Earliest Date

1890

Latest Date

1890

Inscription Date

Material

wood; plastic (ebonite, ivorine); metal (brass); paper

Dimensions

height 346mm; breadth 206mm; depth 180mm

Special Collection

Provenance

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

Inscription

on label: “Am-meter, Instr. No. 168 ( the ‘8’ partially missing ) / Range .0.6 .2 .6 / Constants...”
on dial: “168 / SIEMENS BROS. & CO. LTD / LONDON”
on base: “ 5791 (?)”
on ivorine plate on base (added): “ENGINEERING LABORATORY / CAMB. UNIV.”

Description Notes

Wooden rectangular base; three brass levelling feet; three brass terminals marked ‘1’, ‘3’, ‘2’, providing two different current ranges when terminals 1 & 3 or 2 & 3 are used; brass clamping mechanism; wooden standard supporting single fixed coil; circular white porcelain dial on top with full divided circle, 0 to 400 divisions; ebonite knob and metal pointer on central shaft connected, via suspending spring, to the moving coil and attached pointer ( knob is used to bring pointer on suspended coil back to zero position ); two cups hold mercury for electrical connections to moving coil (no mercury present 20/07/2023) ; cylindrical cardboard cover with brass handle. Paper label on cover providing sensitivity constants, partially illegible.

References

Events