An elementary book on electricity and magnetism and their applications . Fig. 111.— Interior of Thomsonwatt-hour meter. ELECTRICAL MEASURING INSTRUMENTS 177. Fig. 112. Dials of a watt-hour meter read-ing 538 kilowatt hours. of hours during which the power is used. Since the dials recorda total number of kilowatt hours which are added together,or integrated, by a meter during the period that it operates,these meters are some-times called integratingwattmeters. If no external retard-ing force were appliedto the armature of suchan instrument, it would run away as soon as placed in service,and in
An elementary book on electricity and magnetism and their applications . Fig. 111.— Interior of Thomsonwatt-hour meter. ELECTRICAL MEASURING INSTRUMENTS 177. Fig. 112. Dials of a watt-hour meter read-ing 538 kilowatt hours. of hours during which the power is used. Since the dials recorda total number of kilowatt hours which are added together,or integrated, by a meter during the period that it operates,these meters are some-times called integratingwattmeters. If no external retard-ing force were appliedto the armature of suchan instrument, it would run away as soon as placed in service,and in order that its speed may be proportional to the watts,the retarding force must be in proportion to the is ingeniously arranged for by placing at the bottom ofthe spindle a flat disk D of copper or aluminum, on eitherside of which are placed the poles of permanent magnets rotation of the disk between the magnet poles generateselectric currents in it, which according to Lenzs Law are at-tracted by the magnets and retard the motion of the disk. To compensate for inevita-ble friction of the pivots, asmall auxiliary field coil Sis inserted
Size: 3128px × 799px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectmagnetism, bookyear19
