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 current
unbalance. Three phase only.
Voltage
un bal ance
on
three phase power sources
can cause motor current
to become un bal anced
and exces sive heating will
re
sult. Trip
ping of the
over
load protectors and
premature motor failures
can be expected if the
current unbalance exceeds
five percent.
Percent Maximum Current
Current = Difference from x 100
Unbalance Average Current
_______________
Average Current
To determine if motor current
un bal ance is a function of the
motor or the power supply:
1. Label the leads and
the ter mi nals 1, 2, and
3 respectively.
2. Record the amperage
for each lead.
3. Move each lead to the
next terminal (1 to 2, 2
to 3, 3 to 1).
4. Again read the amperage
of each lead.
5. Move each lead to the
next terminal (1 to 3, 2
to 1, 3 to 2).
6. Again read the amperage
of each lead.
7. If the unbalance moves
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.
8. If the current unbalance
exceeds five percent,
nui
sance tripping or
ex ces sive heating will
result.
9. Connect leads for the
lowest percent of
current un bal ance.
f.
Connections and start
components. Single phase
only.
1.
Disconnect all power
from the panel before
making these checks.
2.
Motor winding resistance
read ings.
a. Disconnect all three
motor leads from panel
terminal blocks.
5
b. Using a volt-ohmmeter,
with the scale set
on RX1, measure the
resistance be
tween the
leads with the chart below.
Typical
Motor Resistance
Winding Leads Reading
Main
Black to
Lowest
White
Start
Black to
Next
Red Lowest
(Middle)
Both
White to
Highest
Red
(Main & Start)
3. Capacitor check.
a. Make sure the ca pac i tor
is dis
charged. Use
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 the
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.
