. Hawkins electrical guide. Questions, answers & illustrations; a progressive course of study for engineers, electricians, students and those desiring to acquire a working knowledge of electricity and its applications; a practical treatise. Single or Monoph^eCurrent.—This kind ofalternating current is gen-crated by an alternatorhaving a single winding onits armature. Two wires, alead and return, are usedas in direct current. An elementary diagramshowing the working prin-(iplcs is illustrated in ,249, a similar hydrauliccycle being shown in ,250 to 1,252, Two Phase Current.—■In most
. Hawkins electrical guide. Questions, answers & illustrations; a progressive course of study for engineers, electricians, students and those desiring to acquire a working knowledge of electricity and its applications; a practical treatise. Single or Monoph^eCurrent.—This kind ofalternating current is gen-crated by an alternatorhaving a single winding onits armature. Two wires, alead and return, are usedas in direct current. An elementary diagramshowing the working prin-(iplcs is illustrated in ,249, a similar hydrauliccycle being shown in ,250 to 1,252, Two Phase Current.—■In most cases two jcurrent actually i distinct single |currents flowing in separatecircuits. There is often noelectrical connection be-D them; they are ofequal period and equalamplitude, but differ inphase by one quarter of aperiod. With this phaserelation one of them willbe at a maximum whenthe other is at zero. Twophase current is illustrated A L TERX. 1 77A(7 CI RRENTS 1,021. SINGLE PHASE ALTERNATING CURRENT MAXIMUM VELOCITYREVERSE DIRECTION Figs. 1,2o0 to 1,252.—Hydraulic analogy illustrating the difference between direct (continuous)and alternating current. In fig. a centrifugal pump C forces water to the upperpipe, from which it falls by gravity to the lower pipe B and re-enters the pump. Thecurrent is continuous, always flowing in one direction, that is. it does not reverse its direc- tion. Similarly a direct electric current is constant in direction (does not reverse). m though not necessarily constant in value. A direct current, constant in both value anddirection as a result of constant pressure, is called continuous current. Similarly inthe figure the flow is constant, and a gauge D placed at anv point will register a constantpressure, hence the current may be called, in the electrical sense, continuous. Theconditions in fig. are quite different. The illustration represents a double actingcylinder with the ends connected by a pip
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