Electrical Connection; Bme Hp Feed Pump; Motor Protection; Setting Of Motor Starter - Grundfos BMEX Serie Instrucciones De Instalación Y Funcionamiento

7. Electrical connection

7.1 BME hp feed pump

The electrical connection must be carried out by an authorised
electrician in accordance with local regulations and the diagrams
for the motor protection, starter and monitoring devices used. See
fig. 10. The electrical connections must be made in the terminal
box.
Warning
Before making any electrical connections, make sure
that the power supply has been switched off and that
it cannot be accidentally switched on.
The pump must be connected to an external mains
switch with a minimum contact gap of 3 mm in all
poles.
The pump must be earthed.
95
A1
H1
H2
K
N
A2
98 96
S1
K1
Fig. 10 Wiring diagram, BME hp feed pump
The required voltage quality measured at the motor terminals is -
5 %/+ 5 % of the rated voltage during continuous operation
(including variation in the supply voltage and losses in cables).
Check that there is voltage symmetry in the power supply lines,
i.e. approximately same difference of voltage between the
individual phases. See also section
cable, point 1.
The motor is wound for star-delta starting.
The following starting methods can be used:
• star-delta starting
• soft starter
• frequency converter.
The maximum permissible run-up changeover time for star-delta
starting is 2 seconds for motors up to and including 90 kW and 4
seconds for motors of 110 to 160 kW.
When starting up via a soft starter or frequency converter, the
run-up time from 0 to 30 Hz should not exceed 6 seconds. The
run-out time from 30 to 0 Hz should not exceed 6 seconds.
During frequency converter operation, it is not advisable to run
the motor at a frequency higher than the rated frequency (50 or
60 Hz). See motor nameplate.
8
N L1 L2 L3
FR
3UN2 100-0 C
T2 T1
K1
MV
M
3
23. Checking motor and

7.1.1 Motor protection

The motor must be connected to an effective motor starter (MV)
and an external amplifier relay (FR). See fig. 10. This protects the
motor against damage from voltage drop, phase failure, quick and
slow overloading and a locked rotor.
In power supply systems where undervoltage and variations in
phase symmetry may occur, a phase failure relay should be
connected. See section 23. Checking motor and

7.1.2 Setting of motor starter

For cold motors, the tripping time for the motor starter must be
less than 10 seconds at 5 times the rated current of the motor.
If this requirement is not met, the motor warranty will
Note
be invalidated.
To ensure optimum protection of the motor, the starter overload
unit should be set in accordance with the following guidelines:
1. Set the starter overload to the rated current (I
2. Start the BME hp feed pump, and let it run for half an hour at
normal performance.
3. Slowly grade down the scale indicator until the motor trip point
is reached.
4. Increase the overload setting by 5 %, but not higher than the
rated current (I ) of the motor.
1/1
For motors wound for star-delta starting, the starter overload unit
should be set as above, but the maximum setting should be as
follows:
Starter overload setting = rated current (I

7.1.3 Generator operation

Motor-driven generators for standard motors are often available
according to standard conditions:
• maximum height above sea level: 150 metres
• maximum air intake temperature: 30 °C
• maximum air humidity: 60 %.
Please contact Grundfos for advice.
7.1.4 Thermistor
Before starting up the system, the thermistors must be connected
to terminals T1 and T2 on the terminal block. See fig. 10. The
thermistors protect the motor windings against thermal overload.
cable, point 1.
) of the motor.
1/1
) x 0.58.
1/1