Transcript Universal Current Meter Training Model OSS-B1

Current Meter Maintenance
Model OSSPC1
Hydrographic Training
Bandar Seri Begawan
Brunei
August 2010
Why Is This Important?
• Ensures that induced errors in
measurement from ‘mechanical’ sources
are eliminated
• Prolongs life of current meter and
components
Section 1
Prior to Gauging
Procedure
Important Points
•Dispose of used current meter oil in a thoughtful
manner
•Place components on lint free cloth or paper
•Ensure components do not come into contact with
dust
•Use ONLY approved HS current meter oil (PYG-17)
Spin Test
• Prior to spin test hold
the current meter in the
horizontal position, with
fan facing directly to
your mouth
• Blow air forcefully and
allow fan to spin for
approx. one minute (to
minimise any hydraulic
pressure )
DO NOT SPIN BY HAND
Spin Test
• Spin test the meter
against time (as per
table shown)
• Connect current
meter to the counter
and test operation
Shaft Diameter 4.0mm
Fan No.
Minimum Time
(secs)
1
36
3
13
5
11
Shaft Diameter 2.5mm
Fan No.
Minimum Time
(secs)
1
40
3
15
5
13
Section 2
During and After Discharge
Measurements
General Rule
After every discharge measurement, (or one
hour of use), the current meter should be
disassembled, cleaned, re-filled with oil and
reassembled, if continuing a discharge
measurement.
Procedure
• Remove fan from meter
shaft and dispose of
used oil from meter
body
• Disassemble meter as
shown in Section 1
• Undo the cleaning jar
cap and ‘¾ fill’ with
white spirit
• Place components on
lint free cloth or paper
(do not place in contact
with dirt particles)
• Place shaft in cleaning
jar and agitate in order
to flush out used oil
• Fill body of meter with
white spirit, place thumb
over opening and shake
• Empty and dispose of
white spirit from meter
body
After Discharge Measurements
• Refill with oil if
continuing a
gauging
• Blow dry the shaft
assembly, fan
carrier and fan.
• Assemble ‘dry’ if
meter going into
storage
After Discharge Measurements
• Spin test the current
meter against time
as shown in Section
1
• After the spin test is
performed connect your
current meter to the
counter using the lead,
to test the lead, reed
switch and counter.
Section 3
Office Service
When?
• Once per month (if current meter is used
regularly (daily?)
How?
•Use same procedure described under Section 2
Section 4
Calibration
Calibration
••
Re-calibrate the current meter every 300 hours of
use or once a year which ever comes first (see
Hydrological Services calibration certificate for
details)
••
To minimise freight costs, send only the body and
fans requiring re-calibration
Note: Hydrological Services provides a recalibration and repair service for all types of current
meters.
Section 5
Troubleshooting
MECHANICAL PROBLEMS
SYMPTON
POSSIBLE
CAUSES
ACTION
REMARK
Failed spin test
Dirty bearings
Faulty bearings
Clean bearings
Replace bearings
if problem persists
If fan stops
suddenly towards
end of spin test,
likely cause is
dirty bearings
Failed spin test
Bent shaft
If shaft is bent,
return to HS for
repair or replace
with new shaft
Bent shaft can be
observed by
looking directly at
point of fan during
a spin test. If this
point is turning ‘off
centre’, shaft is
bent
Fan out of balance
Fan squashed or
dropped
Remove the fan,
rotate the shaft
approx. 50° and refit the fan on to the
shaft. If problem
persists return the
fan and body to HS
for repair
If fan stops and
rotates in opposite
direction at end of
spin test, this
indicates that the
fan is out of
balance
ELECTRICAL PROBLEMS (Closed Circuit Fault)
SYMPTON
POSSIBLE CAUSES
ACTION
Fault occurs only when
meter is immersed in water
Water entering contact plug
receptacle and earthing
between body and plug
Replace damaged plug (see
manual)
Circuit closed in any
magnet position, but open
with magnet removed
Reed switch failed
Replace reed switch
assembly
Circuit closed without
magnet in position
Reed damaged
Replace reed switch
assembly
ELECTRICAL PROBLEMS (Open Circuit Fault)
SYMPTON
POSSIBLE CAUSES
ACTION
Open circuit between plug
and insulated reed contact
Faulty plug contact
Clean contact in plug
Re-test
Open circuit between plug
and insulated reed contact
Faulty insulated contact
assembly
Replace
No closure of reed switch
contact when magnet in
position
Damaged reed
Replace
Questions?