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..

MaGrav power measurement

Determining the power of a vacuum cleaner which is connected to the MaGrav Load

Trial period: May to July 2017

Vacuum cleaner: SIMPEX model no. 17730
Power consumption according to the manufacturer: 800W (active power)

Measuring Equipment:

  1. LANDIS & GYR AC meter (375 U / kWh)
  2. ELV Energy Master
  3. Voltcraft VC 170-1
  4. Benning MKII

MaGrav model

experimental magrav
Homemade based on the official Keshe MaGrav Blueprint.


To measure the power consumption of the vacuum cleaner, it was connected to the MaGrav at the output (referred to as load) immediately after purchase and put into operation. This device as indicated by the manufacturer needs 805 watts in normal operation. This value was provided by power meter ELV Energy Master . The vacuum cleaner was idling (new empty dust bag) for about five minutes.

Two days later we measure again under real world conditions. The power meter showed only 630 watts – the value fluctuated by about 20 watts in both directions. If, for example, upholstered furniture was vacuumed, the absorption capacity dropped – if parquet or tiled floors were vacuumed, the absorption capacity increased.

In parallel, the current and voltage were measured to check the values ​​of the power meter. This is accomplished by knowing the cosPhi (power factor) and by known equation:

P = U x I x cosPhi


Measurement with the AC meter

The vacuum cleaner is put into operation and we read the energy consumed on the AC meter in the form of revolutions. For 10 revolutions 128.56 seconds are measured (mobile stopwatch). Under load (suction tube closed at 50%) 167.01 seconds are required for 10 revolutions.

Difference between measurements: 38.45 seconds or 29.90%

This means that the vacuum cleaner draws less energy from the power grid when operating under load. It is therefore completely contrary to the information that the manufacturers themselves make about their devices. See: https: // www. welt.de/wirtschaft/article147904998/Tricksen-Hersteller-beim-Staubsauger-Stromverbrauch.html


Further links

Electrical Power: https://www.elektronik-kompendium.de /sites/grd/0201114.htm

On the subject of a detailed explanation of the determination of power in the AC circuit of Wolfgang Rudolph with capacitive or inductive load and under the influence of the resulting phase shift: https://youtu.be/f39-YXy_xdQ