Hobbs meter

An hour meter is an electrical meter for summing measurement of operating hours, the time it is a device or an electrical load in operation.

Cabinets and equipment

Typical operating hours counter here at 230V AC ( 50 or 60 Hz) and use, for example, whose constant frequency to drive a counting mechanism with a synchronous motor. To view the total elapsed time in hours and have a resolution of 0.01 to 1 hour.

To operate DC voltage and hour meter with stepper and a timer can be used.

Today, operating hours counter is often electronically and have a quartz oscillator as a time standard.

Mercury coulometer

For small devices there are hour meter, in which a mercury droplet apparently traveling in a capillary by the present in operation, constant current flow. Actually, however, is on one side of the drop of metallic mercury in solution, as it is re- deposited from the solution on the other side. Thus, the droplet moves slowly and depends on the current intensity. Strictly speaking, not moving the mercury droplets, but the electrolyte space between the two columns of mercury. This narrow gap is also at the same time the "pointer" of the measuring tube. When the gap reaches one end of the measuring tube, it is " the end" and no longer use. If, however, in good time before the end of the current direction is reversed, the measuring tube in the reverse direction is to continue to use. These operating hours counters are now practically no longer used because of the mercury content, but do because of their small size and the formerly often deliberately hidden application in electronic devices a disposal problem dar.

Aviation

In aviation, the operating hours counter (also Hobbsmeter after John W. Hobbs Corporation founded in 1938 called ) is used in aircraft to determine the operating time of the engine. This results in the maintenance intervals for the aircraft maintenance as well as the rental period.

Older operating hours counter for aircraft possessed a kind of movement with hands for hour display. Today number advertisements are common.

In addition, may still be attached to a flying hours counter which is triggered by aerodynamic forces on the wing leading edge. The flight hour meter is often used in aircraft leasing as a basis for calculation.

The Tach Timer counts the engine revolutions and used to determine the engine maintenance intervals (eg oil change ).

Agricultural machinery and construction machinery

These use an operating hours counter which starts counting with either the ignition or is connected to the D terminal of the alternator and start counting only when the engine is running. The mileage would not be effective due to the stepped Leistungsabgabemaß working speeds.