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