Operation Mode - EBARA E-SPD+ Manual De Instrucciones Y Mantenimento

EN

11 - OPERATION MODE

11a) Constant pressure
1) Single Pump unit
By the direct reading of the pressure transducer, the variable speed drive is responsible for managing the rotation
speed of the electric motor of the pump, guaranteeing the mains pressure remains fixed and unaltered, inside the
pump's performance range regardless of the instantaneous demand for flow required. When the demand for flow is
at its greatest, the pressure of the water network decreases. In this point the pressure transducer, which continuously
informs the inverter of the current pressure, causes the inverter to make the electric motor rotate more quickly,
guaranteeing the established working pressure. In contrast, when the demand for flow decreases, the inverter
makes the electric motor rotate more slowly so the pressure of the water network remains unaffected.
For typical hydraulic installation scheme (figure 1) on page no 382.
2) Unit with several pumps (Multi Inverter)
When there is a network of two or more inverters connected together, the system decides in an alternate and
orderly manner which pump must start up first, when there is demand for flow. Once this pump starts to rotate, if
it stops because there is no more demand for flow, the system will start up a different pump the next time it starts
up, rotating all the pumps that comprise the network of inverters so that all the pumps in the inverter network are
started up the same number of times.
If a pump is running and reaches maximum rotational speed and the network pressure does not reach the
established working pressure, the system will decide whether to start up one more pump, to support the first one or
however many are running at that time. At that time the network of inverters will calculate the rotational speed of
the motors that guarantee the minimum electricity demand at the same time as maintaining the working pressure.
Similarly, and with this same premise of maximum energy savings, the system will continually calculate when it can
disconnect each pump that is running at any time.
11b) Differential pressure
In this mode, inverter maintains a differential pressure between the discharge side and suction side of the pump in
circulation system irrespective of the system flow.
The inverter continuously senses the discharge side and suction side pressure. When the demand for flow is at
greatest, the differential pressure decreases. In this point, inverter causes the electric motor to rotate more quickly,
guaranteeing the set differential pressure. In contrast, when the demand for flow decreases, the inverter makes the
electric motor rotate more slowly so the differential pressure of the water network remains unaffected.
This control mode requires either a differential pressure sensor or 2 pressure transducers of same pressure ratings.
Note: In case of a differential pressure sensor, it is necessary to connect the sensor to analog input 4-20mA (1).
In case of two pressure transducers, it is necessary to connect the discharge side sensor to analog input 4-20mA (1)
and suction side sensor to analog input 4-20mA (2).
For typical hydraulic installation scheme (figure 2) on page no 382.
11c) Fixed speed
In this mode, the inverter maintains a fixed motor speed set by the operator.
The speed of the motor then can be changed manually.
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