P2.x AMEX
underpressure
manometer
sample gas pump
manometer
flowmeter
shut-off valve
Fig. 1: Sample flow diagram of suitable monitoring
4.5 Electrical connections
WARNING
Hazardous electrical voltage
The device must be installed by trained staff only.
WARNING
Inverter operation is forbidden!
WARNING
Regard National directives concerning installation and operation of electrical devices in
hazardous areas when installing and commissioning the motor (e. g. EN 60079-14).
CAUTION
Wrong mains voltage
Wrong mains voltage may damage the device.
Regard the correct mains voltage as given on the type plate.
According to the certification, a switch or power switch must be installed for the motor. It must be easily accessible by the user.
The switch must be marked as circuit breaker for the device. It must not be installed in the mains power cord and must not in-
terrupt the protective earth conductor. Furthermore, it must disconnect the device from all poles.
The device must be operated with the factory-installed motor. The operator must not replace the device or the motor with a dif-
ferent model.
The sample gas pump must be protected against overheating by a suitable overload protection (motor protection switch accord-
ing to the certification).
Regard rated current and settings of the motor protection switch (see type plate of the motor).
In contrast to protection class "Ex nA II", failure mode is monitored in protection class "increased protection". Therefore, the mo-
tor protection switch must switch off within the specified time tE for the respective temperature class if the motor is blocked.
The requirement will be satisfied if the tripping time (it can be picked from the tripping characteristics (initial temperature 20
°C) for the ratio IA/IN) is lower than the specified time tE. (See data sheet 03 and 04 and CE-Type Examination Certificate PTB 02
ATEX 3147.)
Connect the pump according to the circuit diagram inside the terminal cover plate and provide sufficient strain relief of the
mains cable. Make sure that mains voltage and frequency meet the specifications of the motor (voltage tolerance ± 5 % and fre-
quency tolerance ± 2 % based on 220-240 V respectively 110-120 V).
Select mains and PE cross section according to the rated current.
The cross section must be at least 1.5 mm
2
.
Connect the protective earth conductor of the motor to the local earth conductor.
Connect the mounting plate of the pump with means of the press-fitted PE bolt to the local earth conductor. As an alternative, it
is allowed to connect the PE bolt at the mounting plate to the external PE bolt with a cable.
13
Bühler Technologies GmbH
BE420003 ◦ 04/2017
