Systems for measuring shaft vibrations operate according to the eddy-current principle; non-contact measurement of the distance between the probe tip and the rotor surface. The probe has to be set to a distance or GAP of approx. 1.2 mm. A direct current signal proportional to the distance, the GAP voltage, can be measured at the outlet of the transmitter/oscillator/proximitor. Depending on the manufacturer, recommended values range from 8 to 10 VDC.

The setting process can be speeded up considerably with the aid of the GapTester. The GAP voltage is displayed via LEDs in the traffic light colors of red - yellow - green. Arrows below the LEDs indicate the required direction of rotation. When adjusting the distance, the LEDs initially change from red to yellow and then to green, until three green LEDs light up to indicate the optimum distance. The standard GapTester KS02-08/10 is factory set for the switchable GAP voltage values 8 VDC and 10 VDC. Other combinations (e.g. KS02-08/09 or KS02-09/10) are available on request.

The times in which the adjustment of the shaft vibration probes occupied two men over a longer period are over at last. These adjustments can now be performed by one person in just a fraction of the time: Thanks to the magnet on the back of the device, the GapTester can be attached to a convenient position of good visibility; the brightly illuminated LEDs can also be easily read from a distance.

Many of the transmitters/oscillators/proximitors on the market also provide the distance signal via a BNC connector. kmo turbo supplies the GapTester with a BNC-to-measuring-cable adapter or a measuring cable with a BNC connection. If there is no BNC connection, the GapTester has to be connected to the terminals GAP (+) and COM (-), using a standard measuring cable with flying leads or test prods.