Difference between revisions of "Generator Efficiency"

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m (Electrial Efficiency)
m (Electrial Efficiency)
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=Electrial Efficiency=
+
=Electrical Efficiency=
  
 
Efficiency as a fraction input mechanical power that is available at the output terminals:
 
Efficiency as a fraction input mechanical power that is available at the output terminals:
  
 
  E = Pout / (Pout + Ploss)  
 
  E = Pout / (Pout + Ploss)  
 
+
.
  Pout = I^2 * Rl
+
  Pout = I^2 * Rl and Ploss = I^2 * Rm thus
  Ploss = I^2 * Rm
+
  .
 
 
  thus
 
 
 
 
  E = I^2 * (Rl / (Rl+Rm))
 
  E = I^2 * (Rl / (Rl+Rm))
 
+
.
 
  let Rl = k * Rm then
 
  let Rl = k * Rm then
 
+
.
 
  E = k/(1+k)
 
  E = k/(1+k)
 
+
.
 
  for a given desired efficiency keep
 
  for a given desired efficiency keep
 
+
.
 
  Rl >= Rm * E/(1-E)
 
  Rl >= Rm * E/(1-E)
 
+
.
 +
some results:
 
  k = 4 -> 80%  
 
  k = 4 -> 80%  
 
  k = 9 -> 90%
 
  k = 9 -> 90%
 +
 +
=Power Efficiency=
 +
 +
For a load that is a multiple of the genetator resistance, a fraction of the maximum output power is obtained.  If the load equals the genetator resistance, then the maxium output power is obtained.
 +
 +
Let the power efficiency be:
 +
.
 +
Pe = Pout / Pmax
 +
.
 +
some math...
 +
.
 +
Pe = 4k/(1+k)^2
 +
.
 +
Pe of 64% -> k = 4  (80% electrical efficiency)
 +
36% -> k = 9  (90% lectrical efficiency)

Revision as of 08:08, 20 April 2007


Electrical Efficiency

Efficiency as a fraction input mechanical power that is available at the output terminals:

E = Pout / (Pout + Ploss) 
.
Pout = I^2 * Rl and  Ploss = I^2 * Rm thus
.
E = I^2 * (Rl / (Rl+Rm))
.
let Rl = k * Rm then
.
E = k/(1+k)
.
for a given desired efficiency keep
.
Rl >= Rm * E/(1-E)
.
some results:
k = 4 -> 80% 
k = 9 -> 90%

Power Efficiency

For a load that is a multiple of the genetator resistance, a fraction of the maximum output power is obtained. If the load equals the genetator resistance, then the maxium output power is obtained.

Let the power efficiency be:
.
Pe = Pout / Pmax
.
some math...
.
Pe = 4k/(1+k)^2
.
Pe of 64% -> k = 4   (80% electrical efficiency)
36% -> k = 9   (90% lectrical efficiency)