Ee22 Problem Set 1

Problem Set 1:

 Two 1.  Two

500-kW, 250-V, 250-V, under-compound under-compound generators A and B are operating in parallel. The voltage regulation o machines A and B are 2 and ! percent, respectivel". Both machines are operating at rated load and 250 V. #etermine $a% the new &us voltage and $&% the division o load &etween machines when the total &us load drops to 2'00 A.

2.

A short-shunt compound generator has a shunt-(eld resistance o )) ohms, a series-(eld resistance o 0.00' ohm, a commutating-pole winding resistance o 0.005 ohm, and an armature armature resistance, including &rushes, o 0.02 ohm. When the armature current current is *2' A, the generated em is 2!+.2 volts. alculate the power delivered to the load.

3.  The

armature armature o a dc motor has !* slots with * conductors in each slot. nl" ' percent o the conductors lied directl" under the poles aces, where the /u densit" is uniorm at +,000 lines per s1uare inch. inch.  the armat armatur ure-c e-cor ore e diamet diameter er is ).25 ).25 inches inches,, its length length +.25 +.25 inches, and the current in each conductor is 25 amperes, calculate3 $a% the orce eerted &" the armature tending to produce rotation4 $&% the tor1ue in pound-eet. $25 points% points%

4.

A our-pole machine generates 250 volts when operated at *,!50 rpm.  the /u per pole is *.'5  *0 mawells, the num&er o armature armature slots is +5, and the armature winding has two parallel paths, calculate $a% the total num&er o armature armature conductors4 $&% the num&er o conductors in each slot. $25 points% points%

 Two  Two # generators generators are operating operating in parallel parallel and take take e1ual shares shares o a 00kW &us load at 555 V. 6enerator A is rated at 500 kW, 00 V, and ! percent regulation. 6enerator B is rated at )50 kW, 00 V, and 5 percent regulation.   the &us load drops to *000 A, determine $a% new &us voltage4 $&% current supplied &" each machine. 6. A 5-kW *20-volt compound generator has an armature resistance o 0.2! ohm, a series-(eld resistance o 0.0+ ohm, and a shunt-(eld resistance o  5).5 ohms. Assuming a long-shunt connection and a voltage drop at the &rushes o 2 volts, calculate the generated em at ull load. 5.

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