An operating interval is set based on the measured electrical restitution.

According to the invention, in the second operational mode (II) a running time interval (ΔtL2) of the fan (21) at least partially overlaps an idle time interval (ΔtL2) of the compressor (13) in terms of time.

The beading (52) dilates under centrifugal force to provide running clearance.

In addition, an operation interval of a driver circuit can be extended, which results in a reduction in power consumption of a display device.

The solid state timer renders the semiconductor switch non-conductive after it has timed a predetermined maximum operation interval.

Within each duty interval, the bearing load and operating conditions can be averaged to some constant value.

Within each duty interval, the bearing load and operating conditions can be averaged to some constant value.

The number of operating hours or revolutions expected from each duty interval showing the life fraction required by that particular load condition should also be included.

The number of operating hours or revolutions expected from each duty interval showing the life fraction required by that particular load condition should also be included.

The sensing element is configured to sense an activation condition, enable an operation interval of the switching circuit, and transmit a signal to the switching circuit during the activation condition.