It is mainly for that when the vacuum increases, contrary, the power consumption will decrease. To introduce such kind of characteristic, we have prepared a power supply. This power supply can output a stable voltage and stable frequency. While outputting, it will show current and power consumption. The pump we have prepared is UN-200V, a second-version.
We install a vacuum gauge on the suction side to show the current vacuum status. A ball valve will be used later for closing it to form a vacuum status.
Pump running under the state of open flow at 220V/60Hz, It is 3.6 close to 3.7 ampere. The power consumption is about 800W. When the vacuum is starting to build up, as you can see the current and power consumption decrease.
We then gradually increase the vacuum. You can find its variation. Let us to let it reaches to the deepest vacuum now. As you can see that the current drops to 1.6 ampere. The power consumption is just more than 300W. This is because the cylinders in the vacuum pump. When the load drops, It is the physical characteristic, There is no air in the pump head, so it is under vacuum status. It will reduce its load under vacuum status. Correspondingly, the motor load is also reduced. Its power consumption and the current will be dropped, too.
The above is the experiment for which the vacuum rises, the current and power consumption will also decrease.