Multitech 1777.8/7-10 G3 - Manual (Page 10)

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Caution
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Caution
Multitec
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5.4.1 Vacuum balance line
Where liquid has to be pumped out of a vessel under vacuum, it
is advisable to install a vacuum balance line. This line shall have
a minimum nom. diameter of 25 mm and must extend above the
highest permissible liquid level of the vessel.
An additional pipeline fitted with a shut-off valve – from the
pump discharge nozzle to the balance line – facilitates venting
of the pump before start-up.
A Main shut-off valve
B Vacuum balance line
C Shut-off valve
E Vacuum-tight shut-off valve
R Swing check valve
V Vessel under vacuum
Z Intermediate flange
Fig. 11 Suction line and vacuum balance line
5.5 Connection to power supply
Connection to the power supply must be effected by a
trained electrician only (see 5.1)!
The applicable DIN VDE regulations or country-specific
guidelines must be complied with.
Check available mains voltage against the data on the motor
rating plate and select appropriate start-up method.
All connections shall be effected in accordance with the
technical specifications issued by the local energy supply
company.
We strongly recommend to use a motor protection switch.
5.5.1 Connecting the motor
Connect the motor in accordance with the circuit diagram in the
terminal box or as illustrated in fig. 12 or fig. 13.
Prior to starting the motor, check whether the wires
are firmly connected at the terminals and
re-tighten any loose wires.
n configuration (low voltage)
Fig. 12 Connection diagram for three-phase motors,
n
configuration
Y configuration (high voltage)
Fig. 13 Connection diagram for three-phase motors,
Y configuration
5.5.2 Setting the time relay
Make sure that in the case of three-phase motors with star-delta
starting method switching over from star to delta will be effected
at very short intervals. Prolonged switchover intervals may
result in pump damage.
Recommended time relay setting for star-delta starting: 3 to 5
seconds, depending on motor rating.
EN 50014 (DIN VDE 0170/0171 Part 1) stipulates that
explosion-proof motors, type of protection IP 54, increased
safety (Ex)e, thermal class T3, must always be connected via a
motor protection switch.
5.5.3 Checking the direction of rotation
On pumps fitted with uni-directional mechanical
seals (seal codes 62 and 63) the direction of
rotation must never be checked with the pump coupled to the
motor. If the pump/motor coupling does not have to be removed,
make sure that the pump has been primed before checking the
direction of rotation.
The motor’s direction of rotation must correspond to the
direction indicated by the arrow on the pump or motor
(clockwise when seen from the motor end; on version D
anti-clockwise). Verify by switching the motor on and then off
again immediately.
If the pump runs in the wrong direction of rotation, interchange
any two phases L1, L2 or L3 of the power cable in the motor
terminal box.