RESISTANCE DEVICES 



147 



Water Rheostats with Plate and Cylindrical Electrodes. In 

 case there is a running stream or open canal of fresh water near 

 the station and the voltage is high, the forms of rheostat shown in 

 Figs. 73 and 74 are convenient. 



That shown in Fig. 73 was used for absorbing power, up to 700 

 kw., in a 2, 300- volt three-phase circuit. There are three terminal 

 and four neutral plates spaced 4 in. apart on centers, all of iron, 

 the dimensions being 60 in. by 24 in. by J^ in. The frame is 



Via. 73. Three-phase power-absorbing rheostat with plate electrodes. 



hung by a tackle so that the amount of power may be regulated 

 by varying the immersed area. For these immersion rheostats 

 the allowable current density at the electrodes is about 3.5 

 amperes per square inch. 



In the rheostat shown in Fig. 74, which is also designed for 

 three-phase loading, a wooden frame made in the form of an 

 equilateral triangle is provided. The three vertical electrodes 

 are of thin metal pipe and are connected by flexible cables to the 



