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7. Electrical installation
Carry out the electrical connection according to local
regulations.
Check that the supply voltage and frequency
correspond to the values stated on the nameplate.
7.1 Power supply cable
In order to comply with the EN 60335-1 standard, the
power supply cable must as minimum be rated for an
operating temperature of 105 °C (221 °F).
7.2 Motor protection
Single-phase motors, 1 x 115 / 230 V, 60 Hz
These motors do not incorporate motor protection
and must be connected to a motor-protective circuit
breaker which can be manually reset.
Set the motor-protective circuit breaker to maximum
1.15 x I
1/1
.
Other single-phase motors
These motors have built-in current- and
temperature-dependent motor protection in
accordance with IEC 60034-11 and require no further
motor protection. The motor protection is of the TP
211 type which reacts to both slow- and quick-rising
temperatures. The motor protection is automatically
reset.
Three-phase motors up to 3 kW
These motors must be connected to a
motor-protective circuit breaker which can be
manually reset.
Set the motor-protective circuit breaker to maximum
1.15 times full-load current.
Three-phase motors of 3 kW and up
These motors have built-in thermistors (PTC)*. The
thermistors are designed according to DIN 44082.
The motor protection is of the TP 211 type which
reacts to both slow- and quick-rising temperatures.
*
Applies only to motors for the following supply
voltages:
•
3 x 200 V / 346 V, 50 Hz
•
3 x 200-220 V / 346-380 V, 60 Hz
•
3 x 220-240 V / 380-415 V, 50 Hz.
Motors for other supply voltages must be connected
to a motor-protective circuit breaker as described for
three-phase motors up to 3 kW.
7.3 Electrical connection
Carry out the electrical connection as shown in the
diagram inside the terminal box cover.
Fig. 9
Wiring diagram
7.4 Frequency converter operation
You can connect three-phase motors to a frequency
converter.
Depending on the frequency converter type, this may
cause increased acoustic noise from the motor.
Furthermore, it may cause the motor to be exposed
to detrimental voltage peaks.
*
MG 71- and MG 80-based motors with phase
insulation are available on request.
The above disturbances, i.e. both increased acoustic
noise and detrimental voltage peaks, can be
eliminated by fitting an LC filter between the
frequency converter and the motor.
For further information, please contact the frequency
converter supplier or Grundfos.
Warning
The electrical connection must be carried
out in accordance with local regulations.
Before starting work on the pump, switch
off the power supply. Make sure that the
power supply cannot be accidentally
switched on.
The pump must be connected to an
external all-pole mains switch according to
local regulations.
The product must be earthed and
protected against indirect contact in
accordance with local regulations.
Wires connected to supply terminals, must
be separated from each other and from the
supply by reinforced insulation.
TM
03
87
81
10
08
Caution
MG 71- and MG 80-based motors have no
phase insulation* and must therefore be
protected against voltage peaks higher
than 650 V (peak value) between the
supply terminals.
Note
Self-priming pumps only:
If the pump is connected to a frequency
converter, operation at low speed may
cause the internal recirculation valve to
open. This will result in a drop in pressure
and flow.
Summary of Contents for CM
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