Other Motor Manufacturers - Grundfos SP Instrucciones De Instalación Y Funcionamiento

10.7.2 Other motor manufacturers

Hitachi motors
Refer to the Hitachi submersible motors
application maintenance manual.
10.7.3 Franklin motors
Refer to the Franklin submersible motors
application maintenance manual.
10.7.4 Correcting for three-phase power
imbalance
Example: Check for current imbalance for a
230 volt, three-phase, 60 Hz submersible motor,
18.6 full load amps.
Solution: Steps 1 to 3 measure and record
amps on each submersible drop cable lead for
hookups 1, 2 and 3.
Step 1 (hookup 1)
(T ) DL = 25.5 amps
1 1
(T ) DL = 23.0 amps
2 2
(T ) DL = 26.5 amps
3 3
Step 4 Total = 75 amps
Step 5 Average current
Greatest amp difference
Step 6
from the average:
Step 7 % Imbalance
L 1 L 2 L 2 L 3
L 1 L 2 L 3
T 1 T 2 T 3
DL 1 DL 2 DL 3
M 1 M 3
M 2
Hookup 1
Fig. 17
30
Step 2 (hookup 2)
DL = 25 amps
3
DL = 24 amps
1
DL = 26 amps
2
Total = 75 amps
total current
=
3 readings
(hookup 1) = 25 - 23 = 2
(hookup 2) = 26 - 25 = 1
(hookup 3) = 25.5 - 25 = 0.5
(hookup 1) = 2/25 x 100 = 8
(hookup 2) = 1/25 x 100 = 4
(hookup 3) = 0.5/25 x 100 = 2
L 1 L 2 L 3 L 1 L 2
L 1 L 2 L 3 L 1
T 1 T 2 T 3 T 1
DL 3 DL 1 DL 2 DL 2 DL 3
M 1 M 3 M 1
M 2 M 2
Hookup 2 Hookup 3
Observe that hookup 3 should be used since it
shows the least amount of current imbalance.
Therefore, the motor will operate at maximum
efficiency and reliability.
By comparing the current values recorded on
each leg, you will note the highest value was
always on the same leg, L
imbalance is in the power source. If the high
current values were on a different leg each time
the leads were changed, the imbalance would
be caused by the motor or a poor connection.
If the current imbalance is greater than 5 %,
contact your power supply company for help.
* For a detailed explanation of three-phase
balance procedures, see section
with three-phase motors
Step 3 (hookup 3)
DL
DL
DL
Total = 75 amps
75
=
3
L 3
Fused
disconnect
L 2 L 3
Magnetic starter
Manual reset of thermal overload
with extra quick trip heaters
T 2 T 3
DL 1
Submersible drop cable
M 3
Motor
. This indicates the
3
7.1 Startup
on page 15.
= 25.0 amps
2
= 24.5 amps
3
= 25.5 amps
1
= 25 amps