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SELECTING A VIBROCORER |
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Our various submersible models, described in the center pages and further
commented below, essentially differ in terms of portability, mode of vibration,
force, power requirements and depth rating. However, the performance of
a vibrocorer depends in the final analysis upon the capacity of the sediment
particles to move and give way to the coretube with less energy spent
than received. Therefore the best results will always be obtained in unconsolidated,
water-logged, heterogenous sediments.
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| P-3 |
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This lightweight, mid-size model operates in a vibro-percussive
mode and is intended for standard survey work in a variety of sediments.
It is compact, easy to handle and very efficient. Its capabilities approach,
in many sediments, the performances of the more powerful P-5. It requires
a 3-phase, 230 volt or 460 volt, 50-60Hz current. The P-3 is deployed with
a separate non-armored electrocable to about 350 feet (100 m) depths, but
requires a kevlar center cored cable for greater depths. |
| P-5 |
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Our most powerful model, the P-5 houses a
pair of vibrator motors, the same model of vibrator motor as in the P-3,
but in a contra-rotating configuration that doubles the vertical motion
of the unit. Its
twin cylinder housing and compact shape offers easier access to its internal
parts - should, for example, the vibrator motor's wiring harness be switched
between 230v or 460v current. |
| Special Procedures |
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The P-5 has provision for injecting water under
pressure at the top of the coretube in order to perform such special procedures
as water-jetting and incremental coring. |
| *An important note about the power requirements: |
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The P-3 and the P-5 require a 230-460 volt, 3-phase current.
This is the voltage measured at the vibrohead. Voltage losses along the
electrocable should be computed or tested, and taken into account. Usually,
these motors will take an excess voltage of 10% above the rated voltage
but may be damaged and even burnt if the voltage at the vibrohead is below
5% of this rated voltage. In view of such voltage loss, the 460v setting
may be preferred for deepwater work. |
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