280 Mr. E. H. M. Bosanquet on Self regulating 



is a vertical straight line. The actual value of p is in this 

 case indeterminate; it may vary 

 from zero up to the full height l %' ' 



of the straight line vp (fig. 5); 

 and the smallest variations of v 

 will cause it to oscillate between 

 these extreme values. Uniform 

 motion would not be practically 

 possible under an arrangement 

 of this kind, and it does not 

 answer for the governor to be too sharp. A moderate incli- 

 nation represents the case of all practical governors which 

 depend on variation of velocity*. 



These remarks do not apply to phase-governors such as 

 that of my uniform-rotation machine. In this machine the 

 average velocity is always that due to the connexion with the 

 clock; and the governing action is produced by variations of 

 the distance at which the machine follows the clock, so to 

 speak. I believe that governors of this type are in the 

 market. In these cases the power delivered is determined 

 by considerations other than the variation of velocity. 



If in such cases it is desired to impose conditions on the 

 supply of power, the phase, or distance of following the stan- 

 dard motion, must be used to control the governing action, 

 instead of any mechanism depending on absolute changes of 

 velocity. 



We have to deal, secondly, with the relation which re- 

 presents the power absorbed by the machine at different velo- 

 cities. 



Consider the case of machines with constant excitation — in- 

 cluding magneto machines, machines with magnets separately 

 excited, and dynamo machines in which the magnets are 

 saturated. Let S3 be the constant field intensity at right 

 angles to the circumference of the armature, v the velocity, 

 I the effective length of the armature-wire, and E the E.M.F. 

 developed. Then 



E = 33^ in C.G.S. measure, 



power absorbed __ E 2 



P ~U + r 



* It has been said that gas-engine governors are of the infinitely sharp 

 type ; but this is not so. When the impulses are discontinuous and at 

 considerable intervals, the effect of their occasional suppression is distri- 

 buted in the same way as their normal action. The effect of a governor 

 which shut off the steam from an ordinary engine completely on the least 

 rise of speed would be very different. 



