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English (US)
5.5 Instrumentation
The pipe system must include suitable instrumentation for
establishing adequate pump protection. In addition, we
recommend that you include the instrumentation required for on-
site observation of pump operation and performance.
An outlet and inlet pressure gauge is valuable when analyzing
proper pump performance. Furthermore, the pressure gauge can
be used to verify that the pump section is not pressurized when
beginning service procedures.
If you require pump performance control or remote monitoring of
the operating conditions, more instrumentation may be
necessary.
CRN-H MAGdrive pumps have stubs for the connection of
pressure sensors.
Both the inlet and the outlet have connection pieces for a
pressure sensors. These connection pieces have internal threads
(1/4" NPT).
5.6 Electrical installation
5.7 Motors
Grundfos CRN-H MAGdrive pumps are supplied with heavy-duty,
2-pole or 4-pole (3600 rpm or 1800 rpm), TEFC (totally enclosed
fan cooled), NEMA C frame motors.
Motors with other enclosure types and for other voltages and
frequencies are available on a special-order basis.
Pumps with 2-pole motors of 18.5 and 22 kW and 4 pole-motors
as from 1.1 kW must be started via a soft starter or VFD.
5.8 Field wiring
Conductor sizes must be based on the current carrying properties
of conductors required by the latest edition of the National
Electrical Code or local regulations. Direct-on-line (DOL) starting
is approved due to the extremely short run-up time of the motor
and the low moment of inertia of the pump and motor. If DOL
starting is not acceptable and reduced starting current is required,
use an autotransformer, resistance starter or soft starter. We
suggest to use a fused disconnect for each pump in case standby
pumps are installed.
5.9 Motor protection
Three-phase motors
CRN-H MAGdrive pumps with three-phase motors must be used
with the proper size and type of motor-protective circuit breaker to
ensure the motor is protected against damage from low voltage,
phase failure, current unbalance and overloads.
Use a properly sized circuit breaker with manual reset and
ambient-temperature compensated extra-quick trip in all three
phases. The overload protection must be set and adjusted to the
full-load current rating of the motor. Under no circumstances must
the overload protection be set to a higher value than the service
factor current shown on the motor nameplate. This will void the
warranty.
Set overload protection for autotransformers and resistance
starters in accordance with the recommendations of the
manufacturer.
Three-phase motors with a CUE (variable frequency drive)
require only fuses as a circuit breaker. They do not require a
motor-protective circuit breaker. Check for phase unbalance.
WARNING
The safe operation of this pump requires that it is
grounded in accordance with the National Electrical
Code and local codes and regulations. Connect the
ground conductor to the grounding screw in the
terminal box and then to the ACCEPTABLE
grounding point. All electrical work must be
performed by a qualified electrician in accordance
with the latest edition of the National Electrical Code
and local codes and regulations.
WARNING
Check that the supply voltage and frequency
correspond to the values stated on the pump
nameplate.
The pump must be connected to a motor-protective
circuit breaker or a Grundfos CUE frequency
converter.
WARNING
The pump must be connected to an external power
supply located close to the pump and to a motor-
protective circuit breaker or a CUE frequency
converter.
It must be possible to lock the power supply in
position OFF (isolated). Type and requirements as
specified in National Electrical Code and all local
codes.
CAUTION
Standard allowable phase unbalance is 5 %.
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