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Related Concept Videos

Maximum Power Transfer01:16

Maximum Power Transfer

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Numerous practical applications within engineering disciplines, such as telecommunications, necessitate optimizing power delivery to a connected load. This pursuit, however, entails inherent internal losses, which can either equal or exceed the power supplied to the load. The Thevenin equivalent circuit is helpful in finding the maximum power a linear circuit can deliver to a load. It is assumed in this context that the load resistance can be adjusted.
By substituting the entire circuit with...
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Complex Power01:14

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Power engineers have introduced the concept of complex power to determine the cumulative effect of parallel loads. This idea plays a crucial role in power analysis because it encompasses all the details related to the power consumed by a specific load.
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The concept of work involves force and displacement; meanwhile, the work-energy theorem relates the net work done on a body to the difference in its kinetic energy, calculated between two points on its trajectory. While none of these quantities or relations involves time explicitly, we know that the time available to accomplish work is often just as important as the amount of work itself. For example, sprinters in a race may have achieved the same velocity at the finish, therefore,...
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Frequency response analysis in electrical circuits provides vital insights into a circuit's behavior as the frequency of the input signal changes. The transfer function, a mathematical tool, is instrumental in understanding this behavior. It defines the relationship between phasor output and input and comes in four types: voltage gain, current gain, transfer impedance, and transfer admittance. The critical components of the transfer function are the poles and zeros.
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Maximum Power Flow and Line Loadability01:23

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The maximum power flow for lossy transmission lines is derived using ABCD parameters in phasor form. These parameters create a matrix relationship between the sending-end and receiving-end voltages and currents, allowing the determination of the receiving-end current. This relationship facilitates calculating the complex power delivered to the receiving end, from which real and reactive power components are derived.
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Running Functional Threshold versus Critical Power: Same Concept but Different Values.

Alberto A Ñancupil-Andrade1, Santiago A Ruiz-Alias2, Alejandro Pérez-Castilla3

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A 20-minute time trial (TT) can accurately estimate functional threshold power (FTP) and critical power (CP) in athletes. Applying correction factors of 90% for FTP and 95% for CP to a 20-minute TT provides reliable results.

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Area of Science:

  • Sports Science
  • Exercise Physiology
  • Performance Analytics

Background:

  • Functional Threshold Power (FTP) and Critical Power (CP) are key metrics for assessing endurance performance.
  • Accurate determination of FTP and CP is crucial for effective training program design.
  • Shorter, feasible testing protocols are desirable for athletes and coaches.

Purpose of the Study:

  • To estimate FTP and CP using shorter time trials (10, 20, 30 minutes).
  • To determine the accuracy of these shorter time trials in predicting FTP and CP.
  • To assess the position of FTP and CP on the power-duration curve.

Main Methods:

  • Fifteen highly trained athletes completed ten time trials ranging from 1 to 60 minutes.
  • FTP was defined as mean power output over a 60-minute time trial.
  • CP was estimated using a running power meter, with linear regression analyzing shorter time trial data.

Main Results:

  • Acceptable FTP estimates were obtained from 10, 20, and 30-minute time trials with correction factors of 85%, 90%, and 95% respectively.
  • An acceptable CP estimate was achieved only with the 20-minute time trial, using a 95% correction factor.
  • Critical Power was found to be approximately 1W higher than FTP, which was 14W higher than the 30-minute power output.

Conclusions:

  • A 20-minute time trial is a feasible and reliable method for estimating both FTP and CP.
  • Athletes and practitioners can use a 20-minute time trial with specific correction factors (90% for FTP, 95% for CP) for practical assessment.
  • These findings offer a time-efficient approach to power profiling in endurance athletes.