24/7 Magrav power measurement

Anyone who has been running a Magrav in the household for a long time may find that the power consumption of household appliances decreases over time.

We got a good power meter (ELV Energy Master), which shows not only the apparent power (S), but also active power (P), the cosPhi (power factor) as well as voltage (U), current (I) and mains frequency. The following devices are connected via this power meter and run around the clock.

  • 2x LED lamps, 120W per lamp – workshop light (manufacturer writes 300W, but that is not correct., Measurement resulted in 124W)
  • 3x OSRAM DULUX, 23W per lamp – workstation lights
  • 2x fluorescent lamps, 38W per lamp – workplace lights
  • 1x fan, 30W
  • 2x fan each 1W
  • 1x Humidifier Medisana AH 660, 30W
  • 1x mains transformer, 550 VA (to supply all 12V customers, which I can not list all)
  • 1x watervortex, 5W – so we do not die of thirst
  • 3 additional power supplies, 1W per power supply
  • 1x refrigerator, 60W – so we do not starve

All of this equipment runs 24 hours a day, all year round and never shuts off.

The power meter shows us a total load of 464.9 watts (real power). That is now the total consumption of all devices. The values ​​for voltage and current were measured with other measuring devices in order to get as accurate a result as possible and to rule out gross measuring errors or defective devices.

To check the information we have to calculate now.

Apparent power S = U x I

S = 229.9 volts x 2,122 amps = 487.85 VA

The meter shows 488.2 VA – so it’s right, because the mains voltage always fluctuates a bit (they may also within specified tolerances!)

Effective power P = U x I x cosPhi

P = 229.9V x 2.122A x 0.951 = 463.94W

Our meter calculates an active power of 464.9 W – so that’s true.

Manufacturers must write down the energy requirement and other information on each nameplate for each electrical appliance. More detailed information can be found in the manual – usually in the back where no one is looking – in the technical details.

The consumers in total

2x 120W + 3x 23W + 2x 38W + 1x30W + 1x60W are 475W

I will not continue now because we are already above the consumption value that the meter indicates.

If the few lamps, fans and the fridge consume more than the ad tells us, you may ask what has become of the rest. Either all measuring instruments are defective, or the manufacturers deliberately attribute more consumption to their devices than indicated on the rating plate. No idea which manufacturer would need it – in times where saving energy is rewarded would have little sense and it is against the law. In the end, only the Magrav remains as the author. Or you make friends with the idea that some electrical appliances need no energy to run.

Difficult..