caprari PM Serie Instrucciones De Servicio página 17

5.5 Electrical connections and information (when necessary)
The electrical connections must be made by qualified personnel in strict compliance with all the current accident-prevention provisions and
according to the wiring diagrams in the manual and those supplied with the control panels.
All yellow-green ground conductors must be connected to the grounding circuit of the system before the other conductors are
connected. The ground conductors must be the last to be removed if the electric motor is disconnected.
Electrical equipment
Make sure that the electric control panel complies with the current accident-prevention standards and provisions. In particular, the
protection degree should suit the place of installation.
It is advisable to install electrical equipment in dry, well ventilated places. Ambient temperatures should not be extreme (eg. -20 °C to
+40 °C). Failing this, install a special version of the equipment.
ATTENTION The contacts of undersized or poor quality electrical equipment will quickly deteriorate. The motor power supply will
consequently become unbalanced and could damage the motor itself.
Unless it is correctly researched and implemented,use of the INVERTER and SOFT-STARTER can damage the pumping unit . Ask
for assistance from the Caprari Technical Departments if the relative difficulties are not known.
Installation of good quality electrical equipment will ensure reliable and safe operation.
All starting equipment must always be equipped with:
1) main disconnecting switch
2) fuse holders of an adequate size or magnetic protection against short-circuits;
3) quick tripping threepole contactor with a high cutout capacity;
4) quick tripping threepole thermic relay with manual reset at compensated ambient temperature to protect against overloads and phase failures;
- the following are also recommended -
5) a voltmetric relay to protect against voltage drops;
6) a device to protect against dry running;
7) a voltmeter and an ammeter;
8) a restart delay device in the event of a power failure.
Delta connection
W2 (Z) U2 (X) V2
(Y)
U1 (U) V1 W1 (W)
(V)
L1 (R) L2 (S) L3 (T)
Power supply voltage
ATTENTION Make sure that the voltage and frequency ratings on the data plate of the electric motor correspond to those of the electricity main.
Ensure that the appropriate connection either star or delta is selected to suit the power supply.
In particular, remember that the delta connection always refers to the lower value of the two possible voltage ratings. Vice versa for star
connections. The ratio between the two voltage ratings is 1.73.
A ± 10% deviation from the power supply rating is tolerated for motors with data plate ratings of 230/400 V or 400/700 V since such motors can
also operate at 220 and 240, 380 and 415 V ± 5% ratings.
Rotation direction
ATTENTION A wrong rotation direction could damage the motor since in this case, the power draw and axial thrust of the pump could be
much higher than the forecast values.
Identify the exact rotation direction (clockwise for the pump shaft when viewed from the coupling side, see the arrow on the delivery
casing) by proceeding with the following operations:
1) fill the pump and pipe with water (the procedure is described in paragraph 6.1 "Starting");
2) close the delivery sluice valve and start the electric pump for a few moments;
3) if the rotation direction is wrong, disconnect the power source and switch two of the three live wires with each other.
Phase unbalance
Check the power draw on each phase. Unbalances should not exceed 5%.
Higher values could be caused by the motor and/or the electricity main. Check the power draw in the other two motor-main
combinations, making sure that the same rotation direction is maintained.
The optimum connection is that with the least difference in power draw between the phases. Note that if the higher power draw is
always on the same line phase, the main cause of unbalance will be due to the power main.
Caprari S.p.A.
Star connection
W2 (Z) U2 (X) V2
(Y)
U1 (U) V1 W1 (W)
(V)
L1 (R) L2 (S) L3 (T)
For Y - ∆ ∆ ∆ ∆ ∆ starts connection
Remove the plates from the motor terminal
enclosure and reconnect the motor terminals
with the corresponding ones of the starter.
PM
GB
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