112 The N.Z. Journal of Science and Technology. [June 
efficiency would be obtained, for the tendency is to erect the plant in a 
lightly built shed attached to the often antiquated cow-byre, much to the 
detriment of the efficiency. At least one plant was encountered where 
the up-to-date machinery was supported on battens nailed to ordinary 
3 in. by 2 in. uprights lightly bedded in soft ground. In another plant, 
on the other hand, the floor and walls were of solid concrete throughout— 
an object-lesson in efficiency and hygiene. 
The results of the tests on the five plants are summarized and tabulated 
as under. The power-factor is calculated by dividing the observed kilo¬ 
watts, or actual power taken, by the observed kilovolt-amperes, or 
apparent power made up of the actual power-current, combined with the 
idle or magnetizing current of the motors, multiplied by the actual pressure, 
230 volts per phase. 
Plant. 
N umber of 
Cows. 
(Average per 
Day.) 
Number of 
Buckets 
used at a 
Time. 
Kilowatts. 
Amperes. 
Kilovolt¬ 
amperes. 
Power- 
factor 
calculated. 
Units 
used per 
Year. 
A 
45 
3 
0-695 
3-2 
2-21 
Per Cent. 
31 
B 
40 
3 
0-840 
3-4 
2-36 
35 
1,244 
C 
35 
3 
1-140 
3-7 
2-60 
43 
922 
D 
90 
6 
0-560 
3-0 
2-07 
27 
675 
E 
65 
6 
1-500 
3-9 
2-72 
55 
1,919 
The useful conclusions to be drawn from the table are— (a) The low 
power required ; (h) the high value of the idle current and the consequent 
high value of kilovolt-ampere demand; (c) the power taken is very 
variable, and, as before stated, apparently depends much more on the 
efficiency of the plant and the method of use than on the actual number 
of cows milked. 
A record was kept of the consumption of four of the plants for twelve 
consecutive months, and the results are given in the following table, and 
are plotted herewith to show the demand for the various months of the 
year:— 
Plant. 
Jan. 
Feb. 
Mar. 
April. 
May. 
June. 
July. 
Aug. 
Sept. 
Oct. 
Nov. 
Dec. 
Total. 
B 
102 
114 
108 
105 
99 
90 
110 
108 
96 
102 
Ill 
99 
1,244 
C 
102 
138 
81 
115 
66 
54 
24 
3 
24 
105 
108 
102 
922 
D 
81 
96 
67 
65 
39 
18 
9 
12 
33 
87 
90 
78 
675 
E 
190 
186 
180 
162 
123 
87 
78 
87 
153 
198 
225 
200 
1,919 
For the supplier of power or the local authority purchasing in bulk on 
the maximum-demand system the curves show milking-plant load to be 
the ideal, inasmuch as the heaviest load occurs in summer, when no over¬ 
lapping of lighting and power peaks of the main system is likely, and tapers 
away to almost zero for the three worst winter-months when the general 
demand is highest. Further, even in summer the milking-plant load does 
not interfere with the industrial or day peak, owing to its being finished 
