ISBN: 9781153795326

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 illustra… More...

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. 1921 Excerpt: ...in value until the iron in the polepieces becomes saturated. Beyond the saturation point the voltage remains practically constant irrespective of the value of the current in the field coils. By plotting the volts at the armature terminals against the amperes in the field coils, as explained in Chapter XIII the result will be a curve similar to that shown in Fig. 221. Similarly, the effect of the load on the voltage of a generator may be shown in a curve. This is done by connecting a voltmeter across the armature terminals and an ammeter in series in the circuit, as shown in Fig. 223; and after adjusting the voltage to normal, say 110 volts, put a load on the machine of, assume, 30 amperes, as indicated in Fig. 224. This, as shown in Chapter XIII, will cause the voltage to drop at the armature terminals: First, owing to the resistance of the armature, and second, the current in the field coils will also 120 1X) 100 be slightly reduced because of the decrease in volts at the armature terminals. Assume that the volts at the armature terminals decrease 1.5, this will leave Ea = 108.5 volts available at the load and will give point a on curve A, Fig. 222, which is obtained by taking the 30-ampere division at the base of the curve and running up vertically until it intersects the horizontal line running out from the 108.5-volt division, as indicated by the dotted lines. If the load is now increased to 60 amperes, the volts at the armature terminals will further decrease, say to 107; then plotting the load current of 60 amperes against the voltage at the armature terminals, 107 volts, gives point b on the curve. Increasing the load to 90 amperes will cause the voltage to drop accordingly, or, as shown at point c on the curve, to be 105.5. Now, if the load is furth... Fred Anzley Annett, Books, History, Electrical machinery; a practical study course on installation, operation and maintenance Books>History, General Books LLC<

ISBN: 9781153795326

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 illustra… More...

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. 1921 Excerpt: ...in value until the iron in the polepieces becomes saturated. Beyond the saturation point the voltage remains practically constant irrespective of the value of the current in the field coils. By plotting the volts at the armature terminals against the amperes in the field coils, as explained in Chapter XIII the result will be a curve similar to that shown in Fig. 221. Similarly, the effect of the load on the voltage of a generator may be shown in a curve. This is done by connecting a voltmeter across the armature terminals and an ammeter in series in the circuit, as shown in Fig. 223; and after adjusting the voltage to normal, say 110 volts, put a load on the machine of, assume, 30 amperes, as indicated in Fig. 224. This, as shown in Chapter XIII, will cause the voltage to drop at the armature terminals: First, owing to the resistance of the armature, and second, the current in the field coils will also 120 1X) 100 be slightly reduced because of the decrease in volts at the armature terminals. Assume that the volts at the armature terminals decrease 1.5, this will leave Ea = 108.5 volts available at the load and will give point a on curve A, Fig. 222, which is obtained by taking the 30-ampere division at the base of the curve and running up vertically until it intersects the horizontal line running out from the 108.5-volt division, as indicated by the dotted lines. If the load is now increased to 60 amperes, the volts at the armature terminals will further decrease, say to 107; then plotting the load current of 60 amperes against the voltage at the armature terminals, 107 volts, gives point b on the curve. Increasing the load to 90 amperes will cause the voltage to drop accordingly, or, as shown at point c on the curve, to be 105.5. Now, if the load is furth... Fred Anzley Annett, Books, History, Electrical machinery; a practical study course on installation, operation and maintenance Books>History <

ISBN: 9781153795326

Electrical Machinery; A Practical Study Course on Installation Operation and Maintenance Author :Fred Anzley Annett 9781153795326 1153795329, [PU: General Books, LLC]