Auxiliary Running Capacitors
|
Added capacitors must be connected across “Red” and
“Black” control box terminals, in parallel with any existing
running capacitors. The additional capacitor(s) should
be mounted in an auxiliary box. The values of additional
running capacitors most likely to reduce noise are given
below. The tabulation gives the max. S.F. amps normally
in each lead with the added capacitor.
Although motor amps decrease when auxiliary
run capacitance is added, the load on the motor
does not. If a motor is overloaded with normal
capacitance, it still will be overloaded with auxiliary
run capacitance, even though motor amps may be
within nameplate values. |
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| |
Table 15 Auxiliary Capacitor Sizing |
| Motor
Rating |
Normal Running |
Auxiliry Running
Capacitors For |
S.F.
Amps with Run Cap |
| Capacitor(s) |
Noise Reduction |
| HP |
Volts |
Mfd |
Mfd |
Min. Volts |
Franklin Part |
Yellow |
Black |
Red |
| 1/2 |
115 |
0 |
60(1) |
370 |
Two 155327101 |
8.4 |
7.0 |
4.0 |
| 1/2 |
230 |
0 |
15(1) |
370 |
One 155328101 |
4.2 |
3.5 |
2.0 |
| 3/4 |
0 |
20(1) |
370 |
One 155328103 |
5.8 |
5.0 |
2.5 |
| 1 |
0 |
25(1) |
370 |
One
ea. 155328101
155328102 |
7.1 |
5.6 |
3.4 |
| 1 1/2 |
10 |
20 |
370 |
One 155328103 |
9.3 |
7.5 |
4.4 |
| 2 |
20 |
10 |
370 |
One 155328102 |
11.2 |
9.2 |
3.8 |
| 3 |
45 |
None |
370 |
|
17.0 |
12.6 |
6.0 |
| 5 |
80 |
None |
370 |
|
27.5 |
19.1 |
10.8 |
| 7
1/2 |
45 |
45 |
370 |
One ea. 155327101
155328101 |
37.0 |
32.0 |
11.3 |
| 10 |
70 |
30 |
370 |
One 155327101 |
49.0 |
42.0 |
13.0 |
| 15 |
135 |
None |
|
|
75.0 |
62.5 |
16.9 |
|
| |
- Do not add running capacitors to 1/3 through 1 HP control boxes,
which use solid state switches or QD relays. Adding capacitors
will cause switch failure. If the control box is converted to
use a voltage relay, the specified running capacitance can be
added
|
Buck-Boost Transformers
|
When the available power supply voltage is not within
the proper range, a buck-boost transformer is often used
to adjust voltage to match the motor. The most common
usage on submersible motors is boosting a 208 volt supply
to use a standard 230 volt single-phase submersible
motor and control. While tables to give a wide range of voltage boost or buck are published by transformer
manufacturers, the following table shows Franklin’s
recommendations. The table, based on boosting
the voltage 10%, shows the minimum rated
transformer kVA needed and the common
standard transformer kVA. |
Table 15A Buck-Boost Transformer Sizing |
| Motor HP |
1/3 |
1/2 |
3/4 |
1 |
1 1/2 |
2 |
3 |
5 |
7 1/2 |
10 |
15 |
| Load KVA |
1.02 |
1.36 |
1.84 |
2.21 |
2.65 |
3.04 |
3.91 |
6.33 |
9.66 |
11.70 |
16.60 |
| Minimum
XFMR KVA |
0.11 |
0.14 |
0.19 |
0.22 |
0.27 |
0.31 |
0.40 |
0.64 |
0.97 |
1.20 |
1.70 |
| Standard
XFMR KVA |
0.25 |
0.25 |
0.25 |
0.25 |
0.50 |
0.50 |
0.50 |
0.75 |
1.00 |
1.50 |
2.00 |
|
Buck-Boost transformers are power transformers, not control
transformers. They may also be used to lower voltage when the
available power supply voltage is too high. |
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| |
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