What are load calculations for a transformer?

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SUMMARY

Load calculations for transformers involve determining the maximum current based on the transformer's kVA rating and the line voltage. In this discussion, a 44kV line is distributed using eight transformers rated at 3750kVA, 2500kVA, and 1500kVA. The maximum primary current for a 3750kVA transformer is calculated as 49.2 amps per phase using the formula 3750 / (44 / SQRT(3)) / 3. Load distribution among transformers is influenced by their rated power and impedance voltage, with further details available in Transformer Riddle No. 27.

PREREQUISITES
  • Understanding of kVA and its calculation (kVA = volts x amps)
  • Knowledge of three-phase electrical systems
  • Familiarity with transformer impedance voltage
  • Basic electrical engineering principles
NEXT STEPS
  • Study the calculation of maximum current for different transformer ratings
  • Learn about three-phase power distribution systems
  • Explore transformer impedance and its impact on load distribution
  • Review Transformer Riddle No. 27 for detailed load calculation examples
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Electrical engineers, power system designers, and technicians involved in transformer load calculations and distribution systems.

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what are load calculations for a transformer?

A 44kv line is distributed into the industry using around 8 transformers 3750kva, 2500kva and 1500kva. What does this mean and what are the load calculations for this? Also how is it distributed?
 
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KVA is simply volts times amps. And, it's usually three-phase, so you divide the line-to-line voltage by the square root of 3 to find the line-neutral voltage. So, for example, if you have 44 kV into a 3750 kVA transformer, the maximum current will be 3750 / (44 / SQRT (3)) / 3 = 49.2 amps per phase primary current.
 


thank u...
 


Distribution of load on individual transformers is related to their rated power and impedance voltage. For detail calculation you can refer to Transformer Riddle No. 27 from http://electrical-riddles.com
 
Last edited:
Most likely this can only be answered by an "old timer". I am making measurements on an uA709 op amp (metal can). I would like to calculate the frequency rolloff curves (I can measure them). I assume the compensation is via the miller effect. To do the calculations I would need to know the gain of the transistors and the effective resistance seen at the compensation terminals, not including the values I put there. Anyone know those values?

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