Inlet Conditions; Electrical Connection - Grundfos MTH Serie Instrucciones De Instalación Y Funcionamiento

2.3 Inlet conditions

The bottom of the pump strainer must be at least 25
mm above the bottom of the tank. See fig.
MTH pumps must be installed vertically, and the
drain hole in the motor stool must have access to the
tank.
The pumps are designed to provide full performance
down to a level of A mm above the bottom of the
strainer.
At a liquid level between A and B mm above the
bottom of the strainer, the built-in priming screw will
protect the pump against dry running.
Pump type
MTH 2, 4 and 8
MTH 10 and 15
Fig. 6 MTH 2, 4 and 8
Fig. 7 MTH 10 and 15
6 or 7.
A [mm] B [mm]
37 25
40 28
A
B
25mm
A
B
25mm

2.4 Electrical connection

WARNING
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 close
to the pump and to a motor-protective
circuit breaker or a CUE frequency
converter.
- Make sure you can lock the main switch
in OFF position (isolated). Type and
requirements as specified in EN 60204-
1, 5.3.2.
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).
The electrical installation must be carried out by
authorised persons 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.
Single-phase motor
Connect single-phase motors to the mains in
accordance with the instructions located in the
terminal box cover.
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: 220-240 V D / 380-415 V Y
• If the voltage supply is 220-240 V, the motor must
be connected in delta.
• If the voltage supply is 380-415 V, the motor must
be connected in star.
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