Security Devices - Becker VARIAIR DIRECT SCREW 1500 Operating Manual

Changing parameters
According to the parameter overview in section 2.6, only the "adjustable parameters" may be modified cor-
responding to the intended use of the unit. These parameters can be accessed as described in III. When
the parameter to be changed appears in the display of the frequency inverter, it can be changed using the
following combination of keys:
a) key: OK
The parameter to be modified is highlighted by a flashing line.
b) key: left arrow or right arrow
Direct access is gained to the digit position which shall be changed.
c) Key: arrow up or arrow down
The numerical value of the parameter changes.
c) key: OK
The value is acknowledged with OK.

2.3 Security devices

All protective devices installed in the unit are controlled by the frequency inverter. The critical parameters
such as contacts, switches or critical system pressure are continuously updated while the unit is running and
are monitored for eventual emergency or cases that require servicing.
Process air
The transported medium is monitored by the following sensor technology:
• [2] Non return valve: The non-return flap integrated in the suction line (for vacuum) or pressure line (for
compressor) prevent back flowing when the device is switched off.
• [4] Relief valve: If the system pressure increases beyond the factory-set triggering value, then the solenoid valve opens
in the bypass of the suction line (for vacuum) or the pressure line (for compressor). The open magnetic valve will close
as soon as the system pressure exceeds the upper threshold value set by the factory.
Oil circulation
The oil cycle is protected by the following switches or auxiliary contacts.
• [14] Oil level switch: The oil level in the oil tank is monitored by an integrated floater below the driving
motor. A critical decline in the oil level will result in a shutdown of the unit.
• [16] Oil pump: While in operation, the oil pump is monitored by a control contact connected to the
motor contactor. This control contact is activated in case of a short circuit, overcharge or wire breakage,
causing a shutdown of the entire unit.
• [20] Oil temperature switch: The oil temperature is monitored between the outlet of the oil cooler and
the inlet of the oil distributor. The release value is 60°C. If the oil temperature exceeds that threshold
value the unit will be shut down.
• [22] Oil filter control: The degree of soiling of the filter cartridge is monitored by the service contactor
integrated into the housing of the oil filter. The message "Replace oil filter" will appear in the display
of the frequency inverter in regular intervals. The unit will not shut down.
• [23] Oil pump relief valve: The valve is installed in the bypass between oil distributor and oil tank. It
is equipped with a spring which can be adjusted to the desired opening pressure. The oil pump relief
valve prevents the operating pressure of the oil exceeding the permitted value.
• [25] Oil pressure manometer: The manometer is installed between the distributor and the oil inlet on
side a.
• [26] Oil pressure switch: The oil pressure switch features an adjustable switch point. It serves to catch a
too low oil pressure and leads to a switch-off.
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