Additional Protection; Connection Terminals - Grundfos CRE Installation And Operating Instructions Manual

6.4 Additional protection

The total leakage current of all the electrical equipment in the
installation must be taken into account. You can find the leakage
current of the motor in the sections on leakage current and leakage
current (AC).
This product can cause a direct current in the protective ground
conductor.
Overvoltage and undervoltage protection
Overvoltage and undervoltage may occur in case of unstable power
supply or a faulty installation. The motor is stopped if the voltage
falls outside the permissible voltage range. The motor restarts
automatically when the voltage is again within the permissible
voltage range. Therefore, no additional protection relay is required.
The motor is protected against transients from the power
supply according to EN 61800-3. In areas with high
lightning intensity, we recommend external lightning
protection.
Overload protection
If the upper load limit is exceeded, the motor automatically
compensates for this by reducing the speed and stops if the
overload condition persists.
The motor remains stopped for a set period. After this period, the
motor automatically attempts to restart. The overload protection
prevents damage to the motor. Consequently, no additional motor
protection is required.
Overtemperature protection
The electronic unit has a built-in temperature sensor as an
additional protection. When the temperature rises above a certain
level, the motor automatically compensates for this by reducing the
speed and stops if the temperature keeps rising. The motor remains
stopped for a set period. After this period, the motor automatically
attempts to restart.
Protection against phase unbalance
Three-phase motors must be connected to a power supply with a
quality corresponding to IEC 60146-1-1, class C, to ensure correct
motor operation at phase unbalance. This also ensures long life of
the components.
Related information
11.3.2 Leakage current
11.4.2 Leakage current (AC)

6.5 Connection terminals

The descriptions and terminal overviews in this section apply to
both single- and three-phase motors.
For maximum torques, see the section on torques.
Connection terminals, CRE, CRIE, CRNE, CRKE, SPKE, MTRE
and CME pumps
CRE, CRIE, CRNE, CRKE, SPKE, MTRE and CME pumps have a
number of inputs and outputs enabling the pumps to be used in
advanced applications where many inputs and outputs are required.
The pumps have these connections:
• three analog inputs
• one analog output
• two dedicated digital inputs
• two configurable digital inputs or open-collector outputs
• Grundfos Digital Sensor input and output
• two Pt100/1000 inputs
• two LiqTec sensor inputs
• two signal relay outputs
• GENIbus connection.
See fig. Connection terminals, CRE, CRIE, CRNE, CRKE, SPKE,
MTRE and CME pumps.
Digital input 1 is factory-set to be start-stop input where
open circuit results in stop. A jumper has been factory-
fitted between terminals 2 and 6. Remove the jumper if
digital input 1 is to be used as external start-stop or any
other external function.
DANGER
Electric shock
Death or serious personal injury
‐
Make sure that the wires to be connected to the
connection groups below are separated from each
other by reinforced insulation in their entire lengths.
• Inputs and outputs
All inputs and outputs are internally separated from the power
supply-conducting parts by reinforced insulation and galvanically
separated from other circuits. All control terminals are supplied by
protective extra-low voltage (PELV), thus ensuring protection
against electric shock.
• Start-stop: (Digital input 1) = Terminals 2 and 6
• Pressure sensor: (Analog input 1) = Terminals 4 and 8
• Pressure switch: (Digital input 3) = Terminals 6 and 10
• External analog signal input: (Analog input 2) = Terminals 7 and
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• GENIbus Terminals A, Y and B
• Signal relay outputs
- Signal relay 1: LIVE: You can connect supply voltages up to
250 VAC. PELV: The output is galvanically separated from
other circuits. Therefore, you can connect the supply voltage
or protective extra-low voltage to the output as desired.
- Signal relay 2: PELV: The output is galvanically separated
from other circuits. Therefore, you can connect the supply
voltage or protective extra-low voltage to the output as
desired.
• Power supply (terminals N, PE, L or L1, L2, L3, PE).
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