Armstrong Design Envelope 4380 - Switching Frequency; Design Envelope Flow Readout Tolerance

installation &
operating instructions
Design Envelope 4300 & 4380 Vertical
In-line pumping unit with ivs drive
44
4.4.3 switching frequency
The ivs drive controls have an adjustable carrier frequency,
or frequency at which the IGBTs are switched. The switching
frequency aects the performance of the drive and motor and
may produce an audible noise in some instances.
There are 2 pre-set modes available for the Switching
Frequency.
High Eciency Mode - 5kHz, (default)
This frequency setting minimizes the losses in the drive and
motor for optimum performance. However, at this lower set-
ting, the motor may produce an audible high-pitched noise. If
noise is produced and unacceptable, then the drive can be set
to Low Noise Mode.
Low Noise Mode – 12kHz
This frequency setting increases electrical losses, but are less
audible. Set the controls to the Low Noise Mode if the High
Eciency Mode results in unacceptable audible noise.
4.5 design envelope flow readout
tolerance
Tolerance on flow and head readings between test stand in-
strumentation and Design Envelope controller readout will be
within 5% of bep flow & head values for all Design Envelope
sensorless pump selections.
The same bep flow & head tolerance values will be carried
to the Design Envelope selection point for that model
(Guarantee point, to ansi 40.6 Hydraulic Institute Standard-
See fig. 4.5.1), as follows:
fig. 4.5.1
The tolerance is applicable when the flow is between 30%
and 110% of bep flow at Nominal Pump Speed; and the oper-
ating point is at 54% of Nominal Pump Speed, or greater.
Nominal Pump Speed is displayed as the top speed on any
Design Envelope pump curve.
Quadratic pressure
control curve
BEP
Guarantee &
verification point
Verification point
Head curve
Load limiting curve
End of Envelope
Sensorless Limit
Region of
5% flow & head
accuracy
Minimum speed
Nominal
pump speed
54% Nominal
pump speed
30% BEP flow 110% BEP flow
40% Nominal
pump speed
0
0
10
20
30
40
50
60
70
80
100 200 300 400 500 600 700 800
900
Flow (USgpm)
Quadratic pressure control curve
Head (ft)