DAB KVC 70-30 T [23/108] Electrical connections

DAB KVC 70-30 T [23/108] Electrical connections
ENGLISH
18
9.2 Minimum inlet pressure ( Z1 )
To have good performances of the pump avoiding
cavitation phenomenon it is necessary to calculate the
suction lift Z1.
To determine the suction level Z1, the following
formula must be applied:
Z1= pb – rqd. N.P.S.H – Hr – correct pV– Hs
where:
Z1 =
difference in level in metres between the
intake mouth of the pump and the free
surface of the liquid to be pumped.
pb =
barometric pressure in mcw of the place of
installation.( chart 1, pag. 95 )
NPSH =
net load at intake of the place of work.
Hr =
load loss in metres on the whole intake
duct.
pV =
vapour tension in metres of the liquid in
relation to the temperature expressed in
°C. ( chart 2, pag. 96 )
Hs =
safety margin = minimum 0.5 metres head.
If the calculated “Z1” is positive, the pump can
operate at a suction lift of maximum “Z1” metres head.
If the calculated “Z1” is negative, than the pump has
to be fitted with a positive lift of at least “Z1” mt.
Ex. : installation at sea level
and fluid at 20°C
required N.P.S.H: 3,25 m
pb : 10,33 mcw ( chart 1, pag. 95 )
Hr : 2,04 m.
t : 20°C
pV : 0,22 m. ( chart 2, pag. 96 )
Z1 : 10,33 – 3,25 – 2,04 – 0,22 – 0,5 = 4,32 approx.
This means that the pump can operate at a suction lift
of maximum 4,32 metres head.
9.3 Electrical connections
ATTENTION!!
ALWAYS OBSERVE THE SAFETY
REGULATIONS!!
Electrical installation must be carried out by an
authorised, skilled electrician who assumes all
responsability.
THE SYSTEM MUST BE
CORRECTLY AND SAFELY
EARTHED!!
Scrupulously follow the wiring diagrams inside the
terminal board box and those on table C, pag. 94.
 Ensure that the mains voltage is the same as that
shown on the motor data plate.
 The pumps must always be connected to an
external switch.
 Three-phase motors must be protected with an
automatic switch (e.g. circuit breaker) calibrated at
the values shown on the data plate of the
electropump.
 In the case of three-phase motors with star-delta
start, ensure that the switch-over time from star to
delta is as short as possible (see table B, pag. 93 ).
In NKV elecropumps the terminal
board may face in four different
positions: slacken and remove the four
retaining screws between the motor
flange and the support. Turn the motor
into the desired position and replace the
screws.
9.4 Starting
Before starting the pump and the
suction pipe have to be properly
primed pump and pipe have to be fully
filled with clean water.
Starting NKV
In accordance with accident-prevention
regulations, the pump must be run only
if the coupling (where provided) is
suitably protected. So the pump must be
started only after having checked that
the coupling protections are correctly
fitted
.
Fig. 4
pV
NPSH
pb
Hr
Z1

Содержание

DAB ENGLISH 9 2 Minimum inlet pressure Z1 To have good performances of the pump avoiding cavitation phenomenon it is necessary to calculate the suction lift Z1 WATER TECHNOLOGY Ex installation at sea level and fluid at 20 C required N P S H 3 25 m pb 10 33 mew chart 1 pag 95 Hr 2 04 m t 20 C pV 0 22 m chart 2 pag 96 Z1 10 33 3 25 2 04 0 22 0 5 4 32 approx This means that the pump can operate at a suction lift of maximum 4 32 metres head 9 3 Electrical connections A A ATTENTION ALWAYS OBSERVE REGULATIONS Electrical installation must be authorised skilled electrician res ponsability To determine the suction formula must be applied level Z1 the following Z1 pb rqd N P S H Hr correct pV Hs where Z1 difference in level in metres between the intake mouth of the pump and the free surface of the liquid to be pumped pb barometric pressure in mew of the place of installation chart 1 pag 95 NPSH net load at intake of the place of work Hr load loss in metres on the whole intake duct pV vapour tension in metres of the liquid in relation to the temperature expressed in C chart 2 pag 96 Hs safety margin minimum 0 5 metres head If the calculated Z1 is positive the pump operate at a suction lift of maximum Z1 metres head can THE SAFETY carried out by who assumes an all THE SYSTEM MUST BE CORRECTLY AND SAFELY EARTHED Scrupulously follow the wiring diagrams inside the terminal board box and those on table C pag 94 Ensure that the mains voltage is the same as that shown on the motor data plate The pumps must always be connected to an external switch Three phase motors must be protected with an automatic switch e g circuit breaker calibrated at the values shown on the data plate of the electropump In the case of three phase motors with star delta start ensure that the switch over time from star to delta is as short as possible see table B pag 93 In NKV elecropumps the terminal may face in four different positions slacken and remove the four Aboard retaining screws between the motor flange and the support Turn the motor into the desired position and replace the screws 9 4 Starting A If the calculated Z1 is negative than the pump has to be fitted with a positive lift of at least Z1 mt Before starting the pump and the suction pipe have to be properly primed pump and pipe have to be fully filled with clean water Starting NKV A 18 In accordance with accident prevention regulations the pump must be run only if the coupling where provided is suitably protected So the pump must be started only after having checked that the coupling protections are correctly fitted

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