| Percentage of Full Load | 100 | 75 | 50 |
| Penalty | $229.00 | $93.00 | $141.00 |
This evaluation was based on the same time of operation and cost of current as that used in illustration under tests ([Chapter XII]).
The maximum power to be allowed for plants of various capacities should be as follows:
| Capacity in Sweepers | 100% of Load | 75% of Load | 50% of Load | |||
|---|---|---|---|---|---|---|
| 8 | 24 | 20 | 17 | |||
| 6 | 20 | 18 | 15 | |||
| 4 | 14 | 12 | .25 | 10 | .5 | |
| 2 | 7 | .5 | .. | ... | 6 | .25 |
In event that the plant is to be run with vacuum “on tap,” as in a hotel, a guaranteed power consumption at no load should be required and evaluated on the number of hours the plant will probably operate under these conditions. This will be the largest item in the evaluation under such conditions.
CHAPTER XV.
Portable Vacuum Cleaners.
While this book is primarily intended to deal only with vacuum cleaning systems, which would limit the work to such apparatus as is permanently installed within the building to be cleaned, the author considers that it would not be complete without some mention of the portable cleaners which are so popular at the present time.
On first consideration, the portable cleaner would appear to have a considerable advantage over the stationary type in that the length of hose is usually limited to not over 15 ft. and there is no pipe line, which results in the elimination of practically all friction loss, giving practically the same vacuum at the renovator as at the exhauster. This should result in a saving of practically 50% of the power required to operate the exhauster.
Referring to [Chapter XII], we find that the power required to operate a really efficient vacuum cleaning system is approximately 2.5 H. P. per sweeper. If a portable cleaner, with the same efficiency and capacity, be built, it would require at least 1¹⁄₂ H. P.