# Check logic for Watts calculation

• hobbyist5342
In summary, the conversation discusses generating power using a magnet and copper wire. The individual is trying to determine the amount of power generated per hour based on the magnet passing the coil 60 times per minute. However, there is a discussion on the units used and the necessary information needed, such as the load, to accurately calculate the power.
hobbyist5342
Thanks to anyone kind enough to help check my logic. Using 13 gauge copper wire and a magnet I can generate .05 watt every time the magnet passes the coil (according to the voltmeter). Am I correct in assuming that if the magnet passes the coil 60 times a minute, then (.05 watts X 60rpm X 60 min/hr) = 180 watts per hour?

Hi.
Watts is already a rate: J/sec. There is no such unit as "watts per hour". You need to multiply by the duration of the passes to get energy in joules or watt-hours.

hobbyist5342 said:
Thanks to anyone kind enough to help check my logic. Using 13 gauge copper wire and a magnet I can generate .05 watt every time the magnet passes the coil (according to the voltmeter). Am I correct in assuming that if the magnet passes the coil 60 times a minute, then (.05 watts X 60rpm X 60 min/hr) = 180 watts per hour?

What voltmeter do you have that measures power (Watts)? Can you post a picture or say what the model number is?

hobbyist5342 said:
Using 13 gauge copper wire and a magnet I can generate .05 watt every time the magnet passes the coil (according to the voltmeter).

Did you mean "0.05 Volts" ? In which case what you probably got was some sort of pulse that might be displayed as 0.05 Volts. That could be the peak voltage or some sort of average voltage depending on the meter. Either way you can't calculate the power without knowing what the load is. If the load was just the volt meter then it's likely the power was very very low because the resistance of a voltmeter is designed to be high. Connect a known load resistor and repeat the experiment.

If you really did mean "0.05 Watts" then you need to tell us how long it was at 0.05 Watts? If each pass generated 0.05W for half a second and you repeat that once per second (60 times per min) then the average power will be 0.05/2 = 0.025W. That's because half the time it's generating 0.05W and half the time nothing.

If you actually did the “experiment” let’s say you have a good permanent magnet of 2”*2” area and you moved it
with 1m/sec.
E.M.F.=Br*L*v [see: http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/genwir2.html]
E.M.F.=1[Wb/m^2]*[2*2.54/100]*1=0.0508 V
60 RPM=60/60=1 sec/turn. If the length of the wire loop is only 2”[0.0508 m] then the velocity v=0.0508 m/sec, only.
You’ll need 1200 rpm in order to achieve 0.05 V.

## 1. What is the purpose of checking logic for Watts calculation?

The purpose of checking logic for Watts calculation is to ensure that the calculations used to determine the power (in Watts) of a system are accurate and reliable. This is important for making informed decisions and drawing valid conclusions based on the data.

## 2. What factors should be considered when checking logic for Watts calculation?

When checking logic for Watts calculation, it is important to consider the units and conversions being used, the accuracy of the measurements, and any potential sources of error in the calculation method.

## 3. How can errors in Watts calculation be identified?

Errors in Watts calculation can be identified by carefully reviewing the calculation steps, double-checking the units and conversions, and comparing the results to expected values or previous calculations. It can also be helpful to have a colleague review the calculations for a fresh perspective.

## 4. What are some common mistakes when calculating Watts?

Common mistakes when calculating Watts include using incorrect units, forgetting to convert between units, using the wrong formula or equation, and making errors in the calculation steps (such as multiplying instead of dividing).

## 5. How can the accuracy of Watts calculation be improved?

To improve the accuracy of Watts calculation, it is important to use reliable measurement techniques, double-check all units and conversions, and carefully follow the correct formula or equation. It can also be helpful to use multiple methods of calculation and compare the results to ensure consistency.

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