PRESIDENTIAL ADDRESS. 
Three-phase Electromotives on the Italian State Railways. 
eae 034 036 038 050 030 
| Testi y ing- 
Makers + + -+| £4Ganz Ganz Ganz | eee: hye fatan 
Number in Service 2 3 4 40 _ 
Number Building . — — — | 45 16 
Total Weight, tons. 45 62 62 | 60 66 
Weight on Drivers | 45 43°5 43°35 | 60 48 
Number of Driving | 4 3 3 | 5 3 
Axles | 
Total Number of Axles . | 4 by) 5 5 5 
Weight on Drivers,tons | 11°83 14°5 14°5 12 16 
Diam of Drivers, m.m. . | 1,396 1,600 1,600 1,070 1,630 
Frequency (cycles per | 15 15 15 15 162 
second) | 
Method of transmitting | Quill and 
torque of motor to flexible Cranks and Connecting Rods 
driving axles Coupling 
_ Speed, in kilométres per | 30 32—64 22 —45—63) 22°5—49 | 37'9—50— 
hour | | | 75—100 
‘ | ( Cascade 
alee of Speed fe | — / Cascade Cascade | Cascade | and pole- 
ation ° meee | 
(changing | 
The most recent example of single-phase electrification is that of the Loetsch- 
berg line establishing direct communication between Berne and the Simplon line. 
1 am indebted to Dr. Behn-Eschenburg, the designer of the electromotives, for 
the following information. The power at the one-and-a-half-hour rating is 
2,500 horse-power, and the total weight of the engine is 108 tons, of which 
85 tons is taken by the five driving axles. At the normal speed of 50 kilo- 
métres per hour the tractive effort is 10 tons. This can be increased at starting 
to 18 tons. On the heaviest grade (27 per mille) the tractive effort is 13°5 tons, 
which suffices for a train of 310 tons. The maximum speed is 75 kilometres per 
hour. There are two 1,250 horse-power motors on each engine. Each has its own 
transformer and controller, the principle of duplication being carried out in all 
the details, so that in the event of a defect to any one part the other remains 
serviceable. The potential difference between tappings is 45 volts, and the last 
step gives with 15,000 voits on the trolley 520 volts. This is in excess of what 
is required by the motor, and thus provides for the event that the trolley- 
voltage should for some reason fall below the standard pressure. The normal 
voltage of the motors is 420, and the full-load current 2,700 A. At starting on 
the level the line-current is about one-third of the full load-current, and the 
power ten per cent. of the full power. When starting on an up-grade of 27 per 
mille with a train of 310 tons the current taken from the trolley is forty per cent. 
of the normal full-power value, and the acceleration ‘05 metres per second per 
second. ‘he current is taken from the overhead trolley by two pantographs, the 
pressure being 15,000 volts, and the frequency 15. The controller drums are 
each worked by an electromotor and rocking pawls under the electric control of a 
master controller, so that the driver is relieved of any physical exertion in attend- 
ing to the regulation of the motors. These have 16 poles, a compensating wind- 
ing to increase the power-factor, and commutating poles shunted by a non- 
inductive resistance to insure sparkless collection. The power-factor is about 
0.95 over a wide range of load. The motor is geared by double helical wheels 
(ratio 1 : 2°23) to a blind axle, from which the turning moment is transmitted 
to the drivers by cranks and connecting-rods. The weights are as follows: 
Motor, 11°8 tons; gear, 2 tons; transformer, 75 tons; and controller, 1 ton; 
total, 22°3 tons; or at the rate of 17'8 kilogrammes per horse-power on the one- 
and-a-half-hour rating. The total weight of the electromotive is at the rate of 
43 kilogrammes at the same rating. This is a remarkably high weight-etticiency, 
