Selection and sizing
CR, CRI, CRN, CRE, CRIE, CRNE
25
How to read the curve charts
Fig. 27 How to read the curve charts
Guidelines to performance curves
The guidelines below apply to the curves shown on the
following pages:
1. The motors used for the measurements are stand-
ard motors (ODP, TEFC or MLE).
2. Measurements have been made with airless water
at a temperature of 68 °F.
3. The curves apply to a kinematic viscosity of
= 1 mm
2
/s (1 cSt).
4. Due to the risk of overheating, the pumps should not
be used at a flow below the minimum flow rate.
5. The QH curves apply to actual speed with the motor
types mentioned at 60 Hz.
The curve below shows the minimum flow rate as a
percentage of the nominal flow rate in relation to the
liquid temperature. The dotted line shows a CR pump
fitted with an air-cooled top assembly.
Fig. 28 Minimum flow rate
T
M
02
0
0
39
13
03
0
20
40
60
80
100
120
140
160
180
200
Q [US GPM]
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
750
800
850
900
950
1000
[ft]
H
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
750
800
850
900
950
1000
[ft]
H
0
20
40
60
80
100
120
140
160
180
200
220
240
260
280
300
[m]
H
0
5
10
15
20
25
30
35
40
45
Q [m3/h ]
CR(E) 32
2-pole, 60 Hz
CRN(E) 32
-11-2
-10
-1
-1-1
-10-2
-2
-2-1
-2-2
-3
-3-2
-4
-4-2
-5
-5-2
-6
-6-2
-7
-7-2
-8
-8-2
-9
-9-2
0
20
40
60
80
100
120
140
160
180
200
Q [US GPM]
0
1
2
3
4
P2
[hp]
0
20
40
60
80
[%]
Eff
0
1
2
P2
[kW ]
P2 1/1
P2 2/3
Eff
0
10
20
30
NPSH
[ft]
0
10
20
30
[ft]
H
0
4
8
[m]
H
NPSHR
Number of stages.
First figure: number of
stages;
second figure: number of
reduced-diameter impellers.
The eff curve shows the
efficiency of the pump.
The eff curve is an average
curve of all the pump types
shown in the chart.
The efficiency of pumps
with reduced-diameter
impellers is approx. 2 %
lower than the eff curve
shown in the chart.
Pump type, number
of poles and frequency.
QH curve for the individual
pump. The bold curves
indicate the recommended
performance range for
best efficiency.
The power curves indicate
pump input power per stage.
Curves are shown for
complete (1/1) and for
reduced-diameter (2/3)
impellers.
The NPSHR curve is an
average curve for all the
variants shown. When
sizing the pumps, add a
safety margin of at
least 2.0 feet.
TM
02
75
38
37
03
40
60
80
100 120 140 160 180
t [°F]
0
10
20
30
Qmin
[%]
40
60
80
100 120 140 160 180
t [°C]
140 176 212 248 284 320 356
104
