NMM Series
9
6.4.2. Motor Protection
• Three phased-motor shall be connected to power
supply.
• Wait the motor to cool down when thermic protected
motor breaks in circuit due to the overheating. Make
sure the motor does not start automatically until it
cools completely
• In order to protect the motor from overcharging and
short circuit use a thermic or thermic-magnetic relay.
Adjust this relay to the nominal current of the motor.
Electrical equipments, terminals and the components
of the control systems may carry electric current
even though they are not operating. They may cause
deadly and serious injuries or irreparable material
damages.
7. COMMISSIONING, START UP AND OPERATING
7.1. Preparations Before Start Up
• Check mechanical seals of pump.
• Make sure that the pump and the suction pipe is
completely filled with water before the starting. If the
pump operates on a positive suction head, no problem
will be encountered. Suction valve is opened and air
drains are un-tightened.
• Pumps with foot valve are filled with water by
opening the pump filling tap or, one takes advantage of
the water accumulated in the discharge pipe and by
using a small valve the check valve is bypassed and the
pump is filled.
• In vacuum pump driven pumps, by operating the
vacuum pump one achieves to fill the pump via increas-
ing the water level in the suction pipe.
CAUTION
Do not start your pump dry (WITHOUT WATER).
7.2. Checking The Direction of Rotation
CAUTION
• The direction of rotation is indicated on the pump
label with an arrow. Apart from special cases, it is
clockwise direction when looking from the motor end.
Observe if the pump is rotating in the expected sense by
starting the motor for a very short instant. If it is turning
in the opposite sense, interchange any of two motor
leads.
• If the motor connection is delta, open the discharge
valve slowly.
• If the motor connection is star-delta, set the time
relay to maximum 5 seconds. Monitor the passage from
star to delta by pressing the start button. As soon as
you are assured that the connection is delta, open the
discharge valve slowly. Continue opening the valve
until you read the amperage on the electrical panel
• One should always check the labels which show
the direction of rotation and the direction of fluid flow.
If you dismount the coupling protection to monitor the
direction of rotation, do not restart the engine before
remounting the protection.
As a result of getting in touch with rotating and
stable parts each other temperature increase can
occur. Never check the direction of rotation while the
pump is dry.
7.3. Start up Procedure
• Check if the suction valve is open and the discharge
valve is closed. Start the motor
• Wait until the motor reaches sufficient speed. (In
Star-delta connections, wait until the engine passes to
delta connection.)
• Keeping an eye on the amperage shown on the
panel, open the discharge valve slowly.
• In the primary operation, if the discharge pipe is
empty, do not open the valve completely. By keeping an
eye on the amperage, open the valve with care
regarding that it should not exceed the value indicated
on pump’s label.
• After opening the valve completely, check the
pressure from the pump exit manometer and make sure
that this value is the pump operating pressure value
and is indicated on pump’s label.
• If the value one reads is less than the pump label
value when the valve is completely open, it means that
the height is miscalculated. Increase the value by
narrowing the valve and bring it to pump’s label value.
• If the value one reads is greater than the pump label
value when the valve is completely open, it means that
the height is calculated less than what it should be in
reality. The device is pumping less than what is
requested. Check the installation and the calculations.
•
Minimum flow rate:
If the pump is working with zero
flow rates (closed valve) from time to time during its
operation, the water inside the pump may endanger the
pump by getting warmed up. In such cases, a minimum
flow valve must be connected to the pump exit.
CAUTION
Stop the motor if the pump gets too hot. Wait until it
gets cold. Then start the system up again carefully.
