Electrical Measuring Instruments

Electrical Measuring Instruments

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1914 edition. Excerpt: ...insures accuracy throughout the entire range. Connections Types R4 and R6 instruments are made in back connected form only, and are provided with connection studs which also serve to secure the instruments to the switchboard. Finish The standard finish is dull black with raised portions of polished copper. The Type R4 ammeters and voltmeters are exactly like the Type R6 instrument in every way except the size of the case, which is approximately 9 in. in diameter. This instrument corresponds in size to the Type D7 direct current instrument and owing to the longer scale is preferable to the Type R6 for some work. AMMETERS Type R6 ammeters are self-contained in capacities up to and including 600 amperes, Type R4, 200 amperes. Instruments for alternating current use on potentials in excess of 2500 volts or of current capacities greater than 200 amperes will he furnished with current transformers. It is recommended that current transformers be used with all ammeters on circuits of more than 1150 volts, as a safeguard to the switchboard attendant. VOLTMETERS Types R4 and R6 voltmeters are made in capacities up to and including 750 volts, alternating or direct current, and may be used in connection with potential transformers on alternating current circuits of any higher voltage. When ordered with potential transformers the scales are marked in secondary volts unless the order calls for marking in primary volts. When instruments are intended for use with transformers the frequency of the circuit must always be given in order that the proper transformers may be supplied. All voltmeters are furnished with a movable volt marker which is operated by a small screw below the monogram on the dome. The resistance is external in all capacities above 175 volts...show more

Product details

  • Paperback | 32 pages
  • 189 x 246 x 2mm | 77g
  • Rarebooksclub.com
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236615964
  • 9781236615961