Caution, Technical data, Generator sizing – Xylem IM117 R01 5 and Larger Submersible Pump User Manual

Page 10: Generator sizing generator recommendations, Generator recommendations

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10

Technical Data

MOTOR INSULATION RESISTANCE READINGS
Normal Ohm/Megohm readings, ALL motors, between all leads and ground

Condition of Motor and Leads

OHM Value

Megohm Value

New motor, without power cable

20,000,000 (or more)

20.0

Used motor, which can be reinstalled in well

10,000,000 (or more)

10.0

Motor in well – Readings are power cable plus motor

New motor

2,000,000 (or more)

2.0

Motor in reasonably good condition

500,000 to 2,000,000

0.5 – 2.0

Motor which may be damaged or have damaged power cable

Do not pull motor for these reasons

20,000 to 500,000

0.02 – 0.5

Motor definitely damaged or with damaged power cable

Pull motor and repair

10,000 to 20,000

0.01 – 0.02

Failed motor or power cable

Pull motor and repair

Less than 10,000

0 – 0.01

CAUTION

To perform insulation resistance test, open breaker and disconnect all leads from QD control box or

pressure switch. Connect one ohmmeter lead to any motor lead and one to metal drop pipe or

a good ground. R x 100K Scale

Technical Data

Note: Always consult the generator
manufacturer when 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 amperage, phase, hertz, motor type, etc.
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 operating 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. Operating generators at higher
elevations or using natural gas as fuel can affect performance,

consult the generator manufacturer for their recommendations
in these instances.

Generator Sizing

Generator Sizing

Generator Recommendations

Externally Regulated

Internally Regulated

Motor HP KW KVA KW KVA

Minimum Generator Rating

.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

15 40 50 20 25

and

20 60 75 25 31

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

Generator Recommendations

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