Electrical Connection; Starting Up; Stopping; Precautions - DAB KDN 32-125.1 Anleitungen Für Installation Und Wartung

Example 3: installation at sea level and fluid at t = 90°C
required N.P.S.H. : 3.25 m
pb : 10.33 mcw
Hr: 2.04 m
t: 90°C
pV: 7.035 m
Z1 10.33 - 3.25 - 2.04 - 7.035 = -1.99 approx.
In the last case, in order to operate correctly the pump must be fed with a positive head of 1.99 - 2 m, that is the free surface of the water must
be 2 m higher than the axis of the pump.
N.B.: it is always good practice to leave a safety margin (0.5 m in the case of cold water) to allow for errors or unexpected
variations in the estimated data. This margin becomes especially important with liquids at a temperature close to boiling
point, because slight temperature variations cause considerable differences in the working conditions. For example in
the third case, if instead of 90°C the water temperature reaches 95°C at any time, the head required by the pump would no
longer be 1.99 but 3.51 metres.
7.5. Connecting auxiliary systems and measuring instruments.
The realization and connection of any auxiliary systems (washing liquid, seal cooling fluid, dripping liquid) must be considered
when designing the system. These connections are necessary for better and longer lasting pump operation.
In order to ensure continuous monitoring of the pump functions, it is recommended to install a vacuum pressure gauge don the
intake side and a pressure gauge on the delivery side. To check the motor load the installation of an ammeter is advised.
8.

ELECTRICAL CONNECTION

Scrupulously follow the wiring diagrams inside the terminal board box and those on page 1 of this manual.
8.1. 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
and that it falls within table 8.1 on page 119.
8.2. Before opening the terminal board and working on the pump, ensure that the power has been switched off.
8.3. Check the mains voltage before making any connection. If it is the same as the voltage on the data plate, proceed to connect
the wires to the terminal board, giving priority to the earth lead.
8.4. The pumps must always be connected to an external switch.
8.5. The motors must be protected with special remote-control motor-protectors calibrated for the current shown on the plate.
9.

STARTING UP

9.1. Before starting the pump, check that:
- the pump has been properly primed, filling the pump body completely. This ensures that the pump immediately
starts to work regularly and that the seal (mechanical seal or stuffing box seal) is well lubricated. Dry operation
causes irreparable damage to the mechanical seal and the stuffing box seal.
- the auxiliary circuits have been correctly connected;
- all the moving parts have been protected with suitable safety systems;
- the electrical connection has been made as indicated previously;
- pump-motor alignment has been correctly performed.
10. STARTING/STOPPING
10.1. STARTING
10.1.1. Fully open the gate valve on intake and keep the one on delivery almost closed.
10.1.2. Switch on the power and check that the motor is turning in the right direction, that is clockwise when viewed from the fan side.
This check must also be performed after having fed the pump, activating the main switch with a fast start-stop sequence. If the
motor is turning in the wrong direction, invert any two phase leads, after having disconnected the pump from the mains.
10.1.3. Once the hydraulic circuit has been completely filled with liquid, gradually open the delivery gate valve until its maximum allowed
opening. The motor's energy consumption must be checked and compared with the value shown on the data plate, especially
in cases where the pump has intentionally been given a reduced power motor (check the design characteristics).
10.1.4. With the pump running, check the supply voltage at the motor terminals, which must not differ from the rated value by +/- 5%
10.2.

STOPPING

Close the interception device on the delivery pipe. If there is a check device on the delivery pipe, the interception valve on the delivery
side may remain open as long as there is back pressure downstream from the pipe.
If hot water is to be pumped, arrange that the pump can be stopped only after having excluded the source of heat and let sufficient
time elapse to allow the liquid temperature to drop to acceptable values, so as not to create excessive temperature increases
inside the pump body.
For a long period of inactivity, close the interception device on the intake pipe and, if supplied, all the auxiliary control connections.
To guarantee maximum system functionality it will be necessary to arrange for brief running periods (5 - 10 min) at intervals of 1
to 3 months.
If the pump is removed from the system and stored, proceed as indicated in par.5.1
11.

PRECAUTIONS

11.1. The electropump should not be started an excessive number of times in one hour. The maximum admissible value is as follows:
TYPE OF PUMP
THREE-PHASE MOTORS UP TO AND INCLUDING 4 kW
THREE-PHASE MOTORS OVER 4 kW
ENGLISH
MAXIMUM NUMBER OF STARTS PER HOUR
22
100
20