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a. Label the leads and the
ter m i n als 1, 2, and 3
respectively.
b. Record the amperage for
each lead.
c. Move each lead to the next
terminal (1 to 2, 2 to 3,
3 to 1).
d. Again read the amperage
of each lead.
e. Move each lead to the
next terminal (1 to 3, 2 to
1, 3 to 2).
f. Again read the amperage
of each lead.
g. If
the
moves with the motor
leads, the un balance is
caused by the mo tor. If
the unbalance remains
with the terminals, the
un bal ance is in the pow er
supply.
h. If the current unbalance
exceeds five percent, nui-
sance tripping or ex ces-
sive heating will result.
i. Connect leads for the
lowest percent of current
un bal ance.
6. Connections
components. Single phase
only.
a. Disconnect all power from
the panel before making
these checks.
b. Motor winding re sis tance
read ings.
• Disconnect all three
motor leads from panel
terminal blocks.
• Using a volt-ohmmeter,
with the scale set on
RX1, measure the
resistance be tween the
leads with the chart.
12
Winding
Main
Start
Both
c. Capacitor check.
unbalance
and
start
Component
Main Winding
Main Winding
Start Winding
Start Winding
Typical
Motor
Resistance
Leads
Reading
Black to
Lowest
White
Black to
Next
Red
Lowest
(Middle)
White to
Highest
Red
(Main & Start)
• Make sure the ca p acitor
is
dis charged.
Use
extreme caution as a
spark might occur.
• Disconnect the ca pac i tor
leads
and
connect
an analog-type volt-
ohmmeter
to
capacitor terminals.
• Set the meter on the
RX1,000 scale to check
the
start
ca pacitor.
Set the meter on the
RX10,000 scale to
check the run ca pac i tor.
• The
meter
should
in di cate low ohms when
it is first connected,
Typical
Motor
Lead
Black to
White
Black to
White
Black to
Red
Black to
Red
but as the ca pacitor
becomes
(by the meter), it will
return to a read ing of
infinity (open circuit).
d. Start relay check.
• Check coil re s istance.
It should be 3,000 to
15,000 ohms.
• Install a clamp on amp
meter around the start
wind ing lead.
• Set the amp meter scale
to at least 2 times the
pump motor full load
current.
• Place the H-O-A switch
in the Hand position to
start the pump.
the
• The meter should read
ap prox i mate ly 2 times
full load current during
starting.
• After
has
one
cur rent should drop to
a value much less than
full load cur rent.
e. Motor voltage check:
Mode
Start
Run
Start
Run
charged
the
motor
started
(within
sec ond)
the
Voltage
Reading
Line Voltage
Line Voltage
Line Voltage
120%
Line Voltage
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