Grundfos Control MPC-Serie Installationsanleitung Seite 12

6. Overview of control variants
The examples below are based on booster systems.
Systems with speed-controlled pumps
Control MPC-E/-EC
E: Control MPC with three E-pumps.
EC: Control MPC with three pumps, each
connected to a Grundfos CUE frequency
converter.
PT
One E-pump in operation.
H
Hset
Three E-pumps in operation.
H
Hset
• Control MPC-E/EC maintains a constant
pressure 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.
12
Systems with pumps connected to one
CUE frequency converter
Control MPC-F
Control MPC with three pumps connected
to one Grundfos CUE frequency
converter. The speed-controlled operation
alternates between the pumps.
One pump connected to a Grundfos CUE
frequency converter in operation.
H
Hset
Q
One pump connected to a Grundfos CUE
frequency converter and two mains-
operated pumps in operation.
H
Hset
Q
• Control MPC-F maintains a constant
pressure through continuous adjustment
of the speed of the pump connected to the
Grundfos CUE frequency converter. The
speed-controlled operation alternates
between the pumps.
• A pump connected to the Grundfos CUE
frequency converter always starts first. If
the pressure cannot be maintained by the
pump, one or two mains-operated pumps
will be cut in.
• Pump changeover is automatic and
depends on load, operating hours and
fault.
Systems with mains-operated pumps
Control MPC with three mains-operated
pumps.
PT
One mains-operated pump in operation.
Hstop
Hset
Q
Three mains-operated pumps in
operation.
Hstop
Hset
Q
• Control MPC-S maintains an almost
constant pressure through cutting in/out
the required number of pumps.
• The operating range of the pumps lies
between Hset and Hstop (cut-out
pressure).
• Pump changeover is automatic and
depends on load, operating hours and
fault.
Control MPC-S
PT