Overview Of Control Variants - Grundfos Control DDD Montage- Und Betriebsanleitung

7. Overview of control variants

The examples below are based on the possible speed-controlled systems.
Systems with speed-controlled pumps
Control DDD-E
E: Control DDD with three E-pumps.
FT
PT
Fig. 9 System overview, E-pumps
H
H
set
Fig. 12 One E-pump in operation
H
H
set
Fig. 15 Three E-pumps in operation
• Control DDD-E maintains the pressure at
critical points in the system through
continuous adjustment of the speed of the
pumps.
• The system performance is adjusted to
the demand through cutting in/out the
required number of pumps and through
parallel control of the pumps in operation.
• Pump changeover is automatic and
depends on load, operating hours and
fault.
• All pumps in operation run at the same
speed.
• The number of pumps in operation also
depends on the energy consumption of
the pumps. If only one pump is required,
two pumps will be running at a lower
speed if this results in a lower energy
consumption. This requires that the
differential pressure of the pump is
measured and pump curve data are
available for the controller.
Systems with pumps connected to frequency converters
Control DDD-EC
EC: Control DDD with three pumps, each
connected to a Grundfos CUE frequency
converter.
FT
PT
Fig. 10 System overview, frequency
converters
H
H
set
Q
Fig. 13 One pump connected to a
frequency converter in operation
H
H
set
Q
Fig. 16 Three pumps connected to
frequency converters in
operation
• Control DDD-EC maintains the pressure
at critical points in the system through
continuous adjustment of the speed of the
pumps.
• The system performance is adjusted to
the demand through cutting in/out the
required number of pumps and through
parallel control of the pumps in operation.
• Pump changeover is automatic and
depends on load, operating hours and
fault.
• All pumps in operation run at the same
speed.
• The number of pumps in operation also
depends on the energy consumption of
the pumps. If only one pump is required,
two pumps will be running at a lower
speed if this results in a lower energy
consumption. This requires that the
differential pressure of the pump is
measured and pump curve data are
available for the controller.
Control DDD-EF
EF: Control DDD with three pumps, each
connected to a frequency converter.
FT
PT
Fig. 11 System overview, frequency
converters
H
H
set
Q
Fig. 14 One pump connected to a
frequency converter in operation
H
H
set
Q
Fig. 17 Three pumps connected to
frequency converters in
operation
• Control DDD-EF maintains the pressure
at critical points in the system through
continuous adjustment of the speed of the
pumps.
• The system performance is adjusted to
the demand through cutting in/out the
required number of pumps and through
parallel control of the pumps in operation.
• Pump changeover is automatic and
depends on load, operating hours and
fault.
• All pumps in operation run at the same
speed.
• The number of pumps in operation also
depends on the energy consumption of
the pumps. If only one pump is required,
two pumps will be running at a lower
speed if this results in a lower energy
consumption. This requires that the
differential pressure of the pump is
measured and pump curve data are
available for the controller.
Q
Q
11