Electrical Connection; Frequency Converter - Grundfos SE Instrucciones De Instalación Y Funcionamiento

4.2 Electrical connection

DANGER
Electric shock
Death or serious personal injury
- Before starting any work on the product, make
sure that the power supply has been switched off
and that it cannot be accidentally switched on.
Connect the pump to an external main switch
ensuring all-pole disconnection with a contact
separation according to National Electrical Code
(NEC) and all local codes. It must be possible to lock
the main switch in position 0.
The supply voltage and frequency are marked on the
pump nameplate. Make sure that the motor is
suitable for the power supply available at the
installation site.
The electrical connection must be carried out in
accordance with local regulations.
Connect the pump to a controller with a motor
protection relay with IEC trip class 10 or 15 or NEMA
equivalent.
Power supply for the motor protection circuit must be
low voltage, Class 2.
Connect pumps installed in hazardous locations to a
control box with a motor protection relay with an IEC
FM
trip class 10.
– Do not install pump controllers or Ex barriers in
potentially explosive environments.
– The classification of the installation site must be
approved by the local fire-fighting authorities in
each individual case.
– On explosion-proof pumps, make sure that an
external earth conductor is connected to the
external earth terminal on the pump using a
secure cable clamp. Clean the surface of the
external earth conductor and mount the cable
clamp.
– The earth conductor must be minimum AWG 12
type RHH, RHW, RHW-2 or similar, rated for
FM
600 V and minimum 194 °F (90 °C), yellow and
green.
– Make sure that the earth conductor is protected
from corrosion.
– Make sure that all protective equipment has
been connected correctly.
– Float switches used in potentially explosive
environments must be approved for this
application. They must be connected to the
Grundfos Dedicated Controls, DC/DCD or the
SLC/DLC controllers, via an intrinsically safe
barrier to ensure a safe circuit.
If the supply cable is damaged, it must be replaced
by the manufacturer, its service agent or similarly
qualified persons.
Set the motor-protective circuit breaker to the rated
current of the pump + 15 % service factor. The rated
current is stated on the pump nameplate.
If the pump has an FM mark on the nameplate, make
sure that the pump is connected in accordance with
the instructions given in this booklet.
The supply voltage and frequency are marked on the pump
nameplate.
The voltage tolerance at the motor terminals must be within - 10
%/+ 10 % of the rated voltage.
Make sure that the motor is suitable for the power supply
available at the installation site.
The motor is effectively earthed via the power cable and the
pipes. The motor top cover is equipped with connections for
external earthing or an equipotential bonding conductor.
Maintenance and service work on explosion-proof
pumps must be carried out by Grundfos or a service
FM
workshop authorized by Grundfos.
Connect the pump to a motor-protective circuit breaker.
Before installation and the first startup of the pump,
check the condition of the cable visually to avoid
FM
short circuits.
The most commonly used startup methods are these:
• direct-on-line starting (DOL). See appendix, fig. 2.
• star-delta starting (Y/D). See appendix, fig. 1.
• soft start.
You can even start the pump via a frequency converter according
to the frequency converter manufacturer's specifications. See
section

4.2.2 Frequency converter

suitable starting method depends on several considerations on
usage and mains supply conditions.
When using star-delta starting, it is important to keep
switching transient time to a minimum to avoid high
transient torques. We recommend that you use a
time relay with a switching time of maximum 50 ms or
according to the starter manufacturer's
specifications.
operation. The selection of
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