MaintTech CX20 Podręcznik użytkownika - Strona 2

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FUNCTIONS

Press this key to start the instrument and press again to turn off the

instrument.

The instrument also turns off automatically. The instrument shows

"STOP" after 3 minutes. You have 30 seconds to press any key

(not ON/OFF key). Otherwise the instrument will be turned off.

If the Battery voltage is below 5.5V, the instrument will be shut off.

Press this key to change the measurement between Vibration and

Bearing Energy.

Press this key to stop the measurement.

Press again and the measurement will continue.

When the transducer is mounted with the magnet, the frequency range of the

measurement is reduced to approximately 2000 Hz depending on the flatness of the

measuring surface.

When the measuring tip is used, the frequency range is reduced to approximately

500 Hz.

ISO 10816-3 standard allows some higher limits when a foundation is considered

flexible than when if it is rigid. A conclusion from this is also that a resonant condition

in principle is not allowed or at least should be avoided at operation speeds. In practice

this also includes the double speed as well as any other natural excitation frequency

such as blade passage etc.

Modern machines have high speeds, flexible bearing supports and foundations and can

be considered as flexible even if they are not mounted on rubber or springs.

Group 1: Large machines with

Rated power above 300kW.

Electrical machines with shaft height H>315mm.

Operating speed ranges from 120 to 15000rpm.

Group 2: Medium-sized machines with rated power

above 15kW up to and including 300kW.

Electrical machines with shaft height between

160<H<315mm. Operating speed normally above

600rpm.

Group 3: Pumps with multivane impeller and

with separate driver with rated power above 15kW.

Group 4: Pumps with multivane impeller and with

intergrated driver with rated power above 15kW.

The diagram above is only a guide to interpret the Bearing Energy value.

If vibrations of other causes (flow surge, gear mesh) are within in the frequency

range 3200-20000 Hz, this can give a high bearing condition value without the

bearing being damaged.

A high bearing energy value can also be acquired if the bearing is poorly lubricated

or is overloaded (e.g. by misalignment or belt forces).