Flowserve Byron Jackson Type M - Manual (Page 17)

® Byron Jackson Double Mechanical Seal Submersible Pumping Unit • 1042.293/9 • June 04
Page 17 of 68
3.5 Electrical requirements
3.5.1 General electrical requirements
The Byron Jackson submersible motor is designed
for across-line start, eliminating the need for re-
duced voltage starting equipment. Maximum cur-
rent inrush when the motor is connected across the
line at full voltage will be limited to about 700 % of
the rated load current.
Because starting the motor at full voltage results in
high starting torque, the motor accelerates to oper-
ating speed very rapidly (within 0.8 seconds, typi-
cally), and current consumption correspondingly
drops to normal. The rated power requirements of
the motor are stated on the pump nameplate lo-
cated on the wellhead.
Allowed combinations of voltage and frequency
variations during operation are classified according
IEC 60034 as being either Zone A or Zone B
(Figure 3) or according NEMA (see Figure 4).
Figure 3 Voltage and frequency limits acc. IEC 60034
Voltage and frequency limits
-0,1
-0,08
-0,06
-0,04
-0,02
0
0,02
0,04
0,06
0,08
0,1
-0,05 -0,04 -0,03 -0,02 -0,01 0 0,01 0,02 0,03 0,04 0,05
Frequency Variation p.u.
Voltage Variation p.u.
Figure 4 Voltage and frequency limits acc. NEMA
The motor is capable of performing its rated torque
continuously within Zone A, but need not comply
fully with its performance at rated voltage and fre-
quency (see rated point in Figure 3), and may ex-
hibit some deviations. Temperature rises may be
higher than at rated voltage and frequency. For
conditions at the extreme boundaries of Zone A,
the temperature rises and temperatures may ex-
ceed the specified limits of temperature rise and
temperature by approximately 10 K.
Operation outside Zone A (within Zone B) may ex-
hibit greater deviations from its performance at
rated voltage and frequency than in Zone A. Tem-
perature rises may be higher than at rated voltage
and frequency and most likely will be higher than
those in Zone A. Extended operation at the
perimeter of Zone B is not recommended.
Low voltage is a serious problem since the operat-
ing motor current is increased, resulting in addi-
tional motor heating. However, the motor is de-
signed to operate continuously at 110 % of rated
current, so that some reduction in voltage can be
tolerated as long as it is not also accompanied by
an overload of the motor.