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Electrical Applications 2 by David W. Tyler

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76 Transformers
transformers with bar primaries are made for circuits carrying
several thousands of amperes however.
VOLTAGE OR POTENTIAL
TRANSFORMERS
A d.c. ammeter is converted into a voltmeter by the addition of a
series resistor or multiplier which limits the current at full rated volt-
age to that required to give full scale deflection of the movement.
Up to about 1000 V this arrangement is quite satisfactory. Insulat-
ing the meter movement, the terminals and the multiplier from the
case and the panel in which the meter is situated presents no special
problems.
Above 1000
V
hazards begin to present themselves. The cables to