Buck and Boost

Phil Corso

Senior Member
Gentlepeople...

I apologize for the long delay, but my car was broad-sided in a CVS parking-lot, by a driver who lost control while responding to his cell-phone! However, it proved that more than 90% of car accidents happen within a few miles from home!

Here is the correct solution using my Gi.Fi.E.S. method (pronounced Jiffy’s), where:
o Gi means Given
o Fi Find
o EEquation
o S Solution


System Diagram








Given:
o IN and LD subscripts represent Source and Load parameters, respectively!
o Source In: Volts, Amps, Apparent-Power = E[SUB]IN[/SUB] (208V), I[SUB]IN [/SUB]( ? A), VA[SUB]IN[/SUB], respectively!
o Load Data: Volts, Amps, Apparent-Power = V[SUB]LD[/SUB] (240V), I[SUB]LD [/SUB](17A), VA[SUB]LD[/SUB], respectively!
o AT Configuration: Step-Up! Assume ideal, i.e., zero losses and leakage-impedance V-Drops!
o AT Series-Winding: Volts, Amps, Apparent Pwr, = V[SUB]SW[/SUB] ( 32V), I[SUB]SW [/SUB](?A), VA[SUB]SW[/SUB]), respectively!
o AT Common-Wndg: Volts, Amps, Apparent Pwr, = V[SUB]CW[/SUB] (208V), I[SUB]CW [/SUB](?A), VA[SUB]CW[/SUB]), respectively!

Find:
a) VA[SUB]AT[/SUB]: Apparent-Power, by transformer-action, delivered to a 240V, 17A resistive load, from a 208V source!
b) VA[SUB]CA[/SUB]: Apparent-Power, by conduction-action, to the same load!

Equations: Solution:
1) VA[SUB]LD [/SUB]= V[SUB]LD[/SUB] x I[SUB]LD [/SUB]1) 4,080 VA
2) VA[SUB]IN[/SUB] = VA[SUB]LD 2[/SUB]) 4,080 VA
3) I[SUB]IN [/SUB] = VA[SUB]IN [/SUB]/ E[SUB]IN [/SUB]3) 19.62 Amps
4) I[SUB]SW[/SUB] = I[SUB]LD[/SUB] 4) 17.00 Amps
5) I[SUB]CW [/SUB]= I[SUB]IN[/SUB] – I[SUB]SW[/SUB] 5) 2.62 Amps
a) VA[SUB]AT [/SUB]= (V[SUB]LD[/SUB] – V[SUB]IN[/SUB]) x I[SUB]LD[/SUB] (Gar Short-cut) a) 544 VA
b) VA[SUB]CA[/SUB]= VA[SUB]IN[/SUB] x I[SUB]LD [/SUB] b) 3,536 VA

Additional comment:
I’ve been asked a few times, “Why do I use the “Jiffy’s Method” when the “Shortcut” is simpler! I learned why in my second-career job working for a contractor involved in State and Federal Public-Works projects! I realized that countless hours were wasted arguing, quibbling, quarreling, and many times confronted by ‘King-of-the Hill” associates and yes, even bosses! Even witnessed a punch-up, once! The “Jiffy’s Method” cut out all of the above!

Regards, Phil Corso
 

Phil Corso

Senior Member
Ignore previous post!

Gentlepeople…

I apologize for the long delay, but my car was broad-sided in a CVS parking-lot, by a driver who lost control while responding to his cell-phone! However, it proved that more than 90% of car accidents happen within a few miles from home!

Here is the correct solution using my Gi.Fi.E.S. method (pronounced Jiffy’s), where:
o Gi means Given
o Fi Find
o EEquation
o S Solution


System Diagram









Given:
o IN and LD subscripts represent Source and Load parameters, respectively!
o Source In: Volts, Amps, Apparent-Power = E[SUB]IN[/SUB] (208V), I[SUB]IN [/SUB]( ? A), VA[SUB]IN[/SUB], respectively!
o Load Data: Volts, Amps, Apparent-Power = V[SUB]LD[/SUB] (240V), I[SUB]LD [/SUB](17A), VA[SUB]LD[/SUB], respectively!
o AT Configuration: Step-Up! Assume ideal, i.e., zero losses and leakage-impedance V-Drops!
o AT Series-Winding: Volts, Amps, Apparent Pwr, = V[SUB]SW[/SUB] ( 32V), I[SUB]SW [/SUB](?A), VA[SUB]SW[/SUB]), respectively!
o AT Common-Wndg: Volts, Amps, Apparent Pwr, = V[SUB]CW[/SUB] (208V), I[SUB]CW [/SUB](?A), VA[SUB]CW[/SUB]), respectively!

Find:
a) VA[SUB]AT[/SUB]: Apparent-Power, by transformer-action, delivered to a 240V, 17A resistive load, from a 208V source!
b) VA[SUB]CA[/SUB]: Apparent-Power, by conduction-action, to the same load!

Equations:
1) VA[SUB]LD [/SUB]= V[SUB]LD[/SUB] x I[SUB]LD [/SUB]
2) VA[SUB]IN[/SUB] = VA[SUB]LD [/SUB]
3) I[SUB]IN [/SUB] = VA[SUB]IN [/SUB]/ E[SUB]IN [/SUB]
4) I[SUB]SW[/SUB] = I[SUB]LD[/SUB]
5) I[SUB]CW [/SUB]= I[SUB]IN[/SUB] – I[SUB]SW[/SUB]
a) VA[SUB]AT [/SUB]= (V[SUB]LD[/SUB] – V[SUB]IN[/SUB]) x I[SUB]LD[/SUB] (Gar Shortcut)
b) VA[SUB]CA [/SUB]= VA[SUB]IN[/SUB] x I[SUB]LD [/SUB]

Solution:
1) 4,080 VA
2) 4,080 VA
3) 19.62 Amps
4) 17.00 Amps
5) 2.62 Amps
a) 544 VA
b) 3,536 VA

Regards, Phil
 
Top