104 L. Schwendler— On Electric Light Measurements. [MAECnj 
Name of Dynamo- 
Electric Machines. 
K 
Average Current 
in webers. 
c 
1-01 
310 
A and B 
1-12 
310 
D 
1-28 
27-9 
Co-efficient of Efficiency. 
w - -; w is the useful work done in the circuit by the current. 
W —w J 
As the resistance of dynamo-electric machines and leading wires can¬ 
not he made “nil,” this co-eflicient must be always smaller than unity. 
For currents above 24 webers we have :— 
Name of Dynamo- 
Electric Machine. 
€ 
Average Current. 
A 
0-62 
29-5 
B 
0-53 
310 
0 
0-47 
32 6 
D 
030 
27-9 
Hence the dynamo-electric machine A converts 62 ojo of the total 
energy transmitted into useful work, while 38 ojo is lost ill heating the 
machine. 
Dynamo-electric machine D converts 30 ojo of the total energy 
transmitted into useful work, and loses 70 ojo in heating its own wires. 
Practical Mechanical Equivalent of the currents 'produced by Dynamo- 
Electric Machines. 
_W'—w' 
^ j] where C is the current in webers. 
Above 24 webers, the different dynamo-electric machines produce the 
weber at the following consumption of power :— 
Dynamo-electric machines A and B produce one weber at 6S6'5 meg- 
ergs per second. 
Dynamo-electric machine C produces' one weber at 736 meg-ergs per 
second. 1 
