Grundfos MG, Instructions Manual

Page: 10 / 76

English (GB)
10
How to eliminate problems with noise
• Noise-critical applications:
Fit an output filter between the frequency converter and the
motor. This will reduce the voltage peaks and consequently
the noise.
• Particularly noise-critical applications:
Fit a sinusoidal filter. This will reduce the voltage peaks and
optimise the sinusoidal wave of the power supply to the motor.
6.2.3 Cable length
The length of the cable between motor and frequency converter
affects the motor load. Fit a cable that meets the specifications
laid down by the frequency converter supplier.
6.2.4 Speed
Basically, MG motors are not suitable for oversynchronous
operation. Contact Grundfos if oversynchronous operation is
required.
Oversynchronous operation means that the motor runs at a
frequency higher than 60 Hz. This can be achieved by using a
frequency converter.
7. Mechanical installation
The installation must be carried out by authorised personnel in
accordance with local regulations.
Check by hand that the shaft rotates freely.
7.1 Clearance
To ensure sufficient air circulation, a clearance of minimum
50 mm must be available over/around the motor.
7.2 Terminal box positions
Fig. 3 Permissible terminal box positions
In case of vertically installed motors, the terminal box must not
fall more than 10 ° below the horizontal plane.
Make sure that the motor drain holes are positioned so that
condensed water can escape from the motor.
See section
5.2.1 Number of drain holes .
7.3 Outdoor installation
If it is installed outdoors, protect the motor against water and
sunshine.
7.4 Foundation
Grundfos recommends to install motor and pump on a foundation
which is heavy enough to provide permanent and rigid support.
The foundation must be capable of absorbing any vibration,
normal strain or shock.
7.5 Alignment
Correct alignment is important to avoid problems with bearings,
vibrations and possible fracture of shaft ends.
7.6 Fitting of coupling parts and pulleys
Fit coupling parts, pulleys and similar components using suitable
equipment and tools that do not damage the motor bearings.
Never knock a coupling part or pulley into position. Always carry
out removal without pressing against the motor.
8. Electrical installation
8.1 General information
Operating voltage and operating frequency are stated on the
motor nameplate. Check that the motor is suitable for the power
supply available at the installation site.
The voltage quality for MG motors, measured at the motor
terminals, must be ± 10 % of the rated voltage during continuous
operation (including variation in the supply voltage and losses in
cables).
8.1.1 Motor protection
Single-phase motors
Single-phase motors are supplied with built-in thermal protection,
according to IEC 60034-11, against thermal overload with both
rapid and slow variation.
Three-phase motors
Three-phase motors must be protected by a motor-protective
circuit breaker according to local regulations.
MG motors as from 3.0 kW are supplied with thermal switches
(PTC) as standard and protected against thermal overload with
both rapid and slow variation. The motor protection is stated on
the nameplate.
8.2 Electrical connection
The electrical installation should be carried out by authorised
personnel in accordance with local regulations.
The wiring diagram is located in the terminal box cover.
The terminal box of single-speed motors normally contains six
winding terminals and at least one earth terminal.
8.2.1 Single-phase motor
Connect single-phase motors to the mains in accordance with the
instructions located in the terminal box cover.
8.2.2 Three-phase motor
Three-phase motors can be connected in star (Y) or delta (D)
according to IEC 60034-8. See the wiring diagram in the terminal
box cover.
Voltage and connection are stated on the nameplate.
Example: 380-415 D/660-690 Y
• If the voltage supply is 380-415 V, the motor must be
connected in delta.
• If the voltage supply is 660-690 V, the motor must be
connected in star.
TM
04 55
10 330
9
Caution
Non-compliance may result in functional faults
which will damage the motor components.
Warning
Make sure that the power supply cannot be
accidentally switched on during the electrical
installation.
Warning
The motor must be connected to an external
mains switch.
Warning
Whenever motors incorporating a thermal switch
or thermistors are to be repaired, make sure that
the motor cannot start automatically after
cooling.
Warning
Before removing the terminal box cover and
before any dismantling of the motor, switch off
the power supply.
Warning
The motor must be earthed.
Do not connect the motor to the voltage supply
until the connection to earth has been carried out
in accordance with local regulations.