Grundfos DDC Data Booklet

Functions
8
SMART Digital S
3
Functional description
The electronically controlled variable-speed motor
(stepper motor) of the DDA, DDC and DDE pumps
provides optimum control of the stroke speed.
The duration of each discharge stroke varies
according to the capacity set, resulting in optimum
discharge flow in any operating situation, while the
duration of each suction stroke is constant (see figure
below).
The advantages are as follows:
• The pump always operates at full stroke length,
irrespective of the capacity set; this ensures
optimum accuracy, priming and suction.
• A capacity range of up to 1:3000 (turn-down ratio)
reduces variants and spare parts.
• Smooth and continuous dosing ensuring an
optimum mixing ratio at the injection point without
needing static mixers.
• Significant reduction of pressure peaks, preventing
mechanical stress on wearing parts such as
diaphragm, tubes, connections, resulting in
extended maintenance intervals.
• The installation is less affected by long suction and
discharge lines.
• Easier dosing of high-viscosity and degassing
liquids (SlowMode).
The optimum dosing control shown below takes place
in any operation mode.
Fig. 5 Relation between stroke-frequency adjustment and capacity
TM04 1481 0410
100 %
50 %
10 %
Discharge
Discharge
Discharge
Duration
Duration
Duration
Suction
Suction
Suction
Capacity
setting
Duration
10 %
Discharge
Suction
SlowMode
50 %
Extended suction stroke (SlowMode)
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Grundfos DDC Specifications

General

Brand	Grundfos
Model	DDC
Category	Water Pump
Language	English