A student paper 1896

[mivey]

Please clarify. We use power factor today to determine the current associated with real power loss/transfer vs reactive power. Was that not what he was separating in his study?

 

[gar]

170625-0951 EDT

mivey:

Only a moment. Pivot and jewel electrical meter movements did not exist in the late 1870s. Weston in the mid to late 1880s invented a d'Arsonval meter with the jeweled movement.

more when I get back.

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[gar]

170625-1045 EDT

Continuing:

The electrodynamometer type meter was invented:
physics.kenyon.edu/EarlyApparatus/Electrical_Measurements/Electrodynamometer/Electrodynamometer.html

The basic principle was laid out in an 1848 paper by Wilhelm Weber (1804-1891)

The electrical inventor and entrepreneur, Werner von Siemens (1816-1892), used this principle in his electrodynamometer, first described in 1880. In order to measure the power dissipated in an electrical load, it is necessary to measure the current through the load and the potential drop across it. In the Siemens instrument, the stationary coil is made of relatively few turns of heavy wire and is connected in series with the circuit. The rotating coil consists of many turns of fine wire, and is connected across the load with a multiplier resistance in series with it to measure the potential drop. The currents through the two coils are I and a current proportional to V, and the product of the two currents is proportional to the power dissipated in the load.

Fleming worked with two different wattmeters, one was Siemens, and the other was Swinburne. The correlation between the two was very poor.

It appears that Fleming got his best power measurement results from a 3 voltmeter method. He refers to a Fig. 4. for the circuit. I can not find it in his paper. At http://myclassbook.org/three-voltmeter-method/ is a description of the method.

Swainburne was the source of the electrostatic voltmeters.

Fleming was studying transformer power loss. His study does not appear to be concerned with power losses in the supply side of a distribution system with low power factor loads. Rather he seems to be using the power factor equation as a means to evaluate performance of a transformer.

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[gar]

170625-1409 EDT

Very difficult to do Google searches and find useful electrical historical information with dates.

The following relates to watt-hour or ampere-hour meters, but has rough dates that relate to power measurement, even though it is on energy measurement: https://www.metering.com/features/the-history-of-the-electricity-meter/

Fleming describes measurements on two broad classes of transformers --- closed core, and open core. Around 1890 little was known about transformers and that is why Fleming and Stienmetz were working on experiments and theoretical analysis of transformers.

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[gar]

170625-1453 EDT

If I run an experiment similar to what Fleming did, then I get similar results.

Using a 175 VA closed core transformer.

No secondary load.
119.5 V, 0.17 A, 3.9 W, 20.8 VA, 0.18 PF

With resistive 5 ohm load.
120.3 V, 0.40 A, 44.6 W, 48.6 VA, 0.92 PF
14.2 V, 40.3 W 90% efficiency

With resistive 2.5 ohm load.
120.0 V, 0.71 A, 84.2 W, 85.7 VA, 0.97 PF
14.0 V, 78.4 W 93% efficiency

Since this power factor is high it means the leakage flux is small..

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[mivey]

170622-0741 EDT
It appears that Fleming created and used his power factor equation to evaluate transformer losses. Not quite the same as our use of the equation.

170625-1045 EDT
His study does not appear to be concerned with power losses in the supply side of a distribution system with low power factor loads. Rather he seems to be using the power factor equation as a means to evaluate performance of a transformer.

Fleming clearly defined it as the ratio of real to apparent power. He also discussed it in terms of a general AC circuit. Described it as cosine theta for sinusoidals. The whole nine yards. Just what we have today for the term power factor.

I do not see where you have shown it to be any different or not the power factor we know today. The fact that he used it for one type analysis rather than for a distribution circuit analysis makes no difference. It is the same power ratio as used for many different types of analysis and he coined the term.

 

[mivey]

In my response in the other thread, I mentioned some of Swinburne's work:

...

What Mr. Swinburne may have proposed first was the use of condensers by central station operators to help offset the lagging system characteristics and make the system more efficient but I don't have an exact paper for that. Others were using synchronous motors and other such techniques to offset lagging vars.

In the paper's discussion, Swinburne's idea of using condensors to offset lagging power was criticized harshly but that is exactly what we do on distribution systems and a lot at the transmission/generation level. At the generation level we also have var plants.

If you go back to the 1830's, 40's, 50's a lot of things we consider common electrical knowledge were still being discovered and hotly debated by the big minds of the day. By the early 1900's much of that basic electrical knowledge had been ironed out and is in common use today, even by kids.

It is odd to think what we consider simple knowledge and learn in the blink of an eye, even one simple piece of circuit knowledge, was developed by many years of hard work and experimentation.

I wonder as we go forward how much knowledge can be compressed into K-12 and even 4 years of college. At some point do we peak the human capacity to advance? In the past you could be an expert in many fields but as knowledge increases and people become specialists (you simply can't learn everything) do we lose the cross-link ability?

 

[gar]

170709-1648 EDT

mivey:

I will get back to these discussions at some later time, possibly quite a bit later.

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