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85% of full volt age to pull
in without chatter. If the
problem is a re cur ring
one, measure voltage with
recorder on a 24 hour basis.
d. Make sure the floats are
locat ed away from any
turbu lence.
e. Dry out the junction box
(if furnished); moisture
in the junction box may
cause relays to energize
intermittent ly.
6. Short cycling pump.
a. Check float controls.
7. Run light stays on.
a. Selector switch may be in
the Hand position.
8. Nuisance tripping of
over load on motor starters
or cir cuit break ers.
a. Check pump and draw with
amp probe and compare to
nameplate amps on pump.
b. The impeller may be locked
up due to excessive debris
or solids.
c. Possible motor failure (fault
in windings).
d. Pump may be miswired to
ter mi nal block.
e. Voltage
and
unbalance. Three phase only.
Voltage
un bal ance
three phase power sources
can cause motor current
to
become
and exces sive heating will
re sult.
Trip ping
over load
protectors
premature motor failures
can be expected if the
current unbalance exceeds
five percent.
Percent
Current =
Unbalance
To determine if motor current
un bal ance is a function of the
motor or the power supply:
1. Label the leads and
2. Record the amperage
3. Move each lead to the
4. Again read the amperage
5. Move each lead to the
6. Again read the amperage
7. If the unbalance moves
8. If the current unbalance
current
9. Connect leads for the
on
f. Connections
components. Single phase
un bal anced
only.
1. Disconnect
of
the
from the panel before
and
making these checks.
2. Motor winding resistance
read ings.
a. Disconnect all three
Maximum Current
Difference from
x 100
Average Current
_______________
Average Current
the ter mi nals 1, 2, and
3 respectively.
for each lead.
next terminal (1 to 2, 2
to 3, 3 to 1).
of each lead.
next terminal (1 to 3, 2
to 1, 3 to 2).
of each lead.
with the motor leads,
the un bal ance is caused
by the mo tor. If the
unbalance
remains
with the terminals, the
unbal ance is in the
pow er supply.
exceeds five percent,
nui sance tripping or
ex ces sive heating will
result.
lowest
percent
of
current un bal ance.
and
start
all
power
motor leads from panel
terminal blocks.
b. Using a volt-ohmmeter,
with
the
on RX1, measure the
resistance be tween the
leads with the chart below.
Typical
Motor
Resistance
Winding
Leads
Reading
Main
Black to
White
Start
Black to
Red
(Middle)
Both
White to
Red
(Main & Start)
3. Capacitor check.
a. Make sure the ca pac i tor
is
dis charged.
extreme caution as a
spark might occur.
b. Disconnect the ca pac i tor
leads and connect an
analog-type volt-ohmmeter
to the capacitor terminals.
c. Set the meter on the
RX1,000 scale to check
the start ca pac i tor. Set the
meter on the RX10,000
scale
to
check
run ca pac i tor.
d. The meter should in di cate
low ohms when it is first
connected, but as the
ca pac i tor becomes charged
(by the meter), it will
return to a read ing of
infinity (open circuit).
4. Start relay check.
a. Check the start relay coil
re sis tance. It should be
3,000 to 15,000 ohms.
b. Install a clamp on amp
meter around the start
wind ing lead.
scale
set
Lowest
Next
Lowest
Highest
Use
the
5
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