Centripro, Residential water systems, Generator sizing – Xylem BMAID R4 User Manual
Page 42
PAGE 42
Residential Water Systems
CentriPro
Note: Always consult the generator
manufacturer whenever questions arise.
These sizing charts are recommendations based on
motor service factor loading for typical continuous
duty generators. If you need to call the generator
manufacturer, be prepared to tell them the motor KVA
code, the service factor amperage, locked rotor am-
perage, phase, hertz, motor type, etc. This information
can all be found in this manual.
Please note that the 2-wire chart is only for PSC
(permanent split capacitor) type, 2-wire motors and
should not be used for split-phase, 2-wire motors. If
using split-phase, 2-wire motors the generator should
be 50% larger than that listed for a 3-wire motor.
You must know which type generator you have before
using the charts as the required generator size varies
by type. Internally regulated generators are also called
self-excited. Externally regulated generators are the
most common. In addition to the Kw/KVA rating, the
generator frequency (Hertz, typically 60 HZ in USA) is
very important when operating pumping equipment
because frequency variations affect pump output in
direct relation to the pump Affinity Laws. Operating
under 60 hertz will reduce flow and head while op-
erating over 60 hertz will increase flow, head, HP and
amp draw and could overload the motor.
The generator should always be started before the
pump/motor is started and always stop the pump/
motor before shutting down the generator. Operat-
ing generators at higher elevations or using natural
gas a fuel can affect performance, consult the genera-
tor manufacturer for their recommendations in these
instances.
GENErator SIzING
GENErator rECommENDatIoNS
Externally regulated
Internally regulated
motor
hp
kw
kVa
kw
kVa
minimum Generator rating
pSC .5 2.5 3.1 1.75 2.2
type .75 3.5
4.4
2.5
3.1
2-wire 1
5
6.3
3.2
4
1Ø 1.5 6
7.5
4
5
.5
2
2.5
1.5
1.9
.75
3
3.8
2
2.5
1
4
5
2.5
3.2
1.5
5
6.3
3
3.8
2
7.5
9.4
4
5
3
10
12.5
5
6.3
5
15
18.8
7.5
9.4
7.5
20
25
10
12.5
3-wire
10
30
37.5
15
18.8
1Ø
15 40 50
20
25
and
20 60
75
25
31
3Ø
25 75 94
30 37.5
motors
30
100
125
40
50
40
100
125
50
62.5
50
150
188
60
75
60
175
220
75
94
75
250
313
100
125
100
300
375
150
188
125
375
469
175
219
150
450
563
200
250
175
525
656
250
313
200
600
750
275
344