
50 Shipboard Electrical Power Systems
Example 2.4
A water pumping line has a chain of equipment in series as shown below from
the prime mover to the end pump that must deliver 1000 hp output. The motor
is powered via cable and a step-down transformer connected to a dedicated
3-phase generator. Assume the following efficiencies: generator 97%, transformer
98%, cable 99%, motor 96%, and pump 95%. Determine the prime mover hp
rating required for this pumping system.
Generator
Eff. 97%
PM
Transformer
Eff. 98%
Cable Eff. 99%
Motor
Eff. 96%
Pump
Eff. 95%
Pump
output
1000 hp
G
M
P
SOLUTION
The efficiencies of series equipment multiply; hence, the total efficiency ...