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www.cps-pumps.com
IOM Manual: IOM-0000-CST
Series CST: Submersible Turbine
01/01/2018 - Edition 1A
PROBLEM
POSSIBLE CAUSE
RECOMMENDED REMEDY
Problem #7.0
Overload Protector Trips
7.1
Incorrect control box.
Replace with correct control box.
7.2
Incorrect, loose or corroded electrical
connections.
Replace defective item. Refer to ELEC-
TRICAL TESTS.
7.3
Incorrect voltage.
Correct line voltage.
7.4
Current overload.
Check for:
1. Tight motor or pump bearing.
2. Pump clogged with sand.
3. Unbalanced voltage.
4. Grounded cable, splice or motor
winding. Refer to ELECTRICAL
TESTS.
5. Low Voltage.
6. Insufficient cooling of motor.
ELECTRICAL TESTS
MEASURING INSULATION RESIS-
TANCE (GROUND TEST)
The condition of the insulation around a conductor can be
determined by measuring the electrical resistance between the
conductor and ground. This measurement can be made with
a meggar or an ohm-meter. The value is stated in ohms or
megohms (ohms x 1,000,000). High ohm values indicate good
insulation.
The basic procedure for measuring insulation resistance is given
below:
Turn off all power and disconnect the leads to be tested from the
electrical panel.
Do not touch any bare wires or allow bare wires to come in con-
tact with the ground or metal. False readings will result.
If the meter needle is at either extreme end of the scale, a more
accurate reading can be obtained by switching the selector
switch to another scale. Re-zero the meter each time the selec-
tor switch is moved.
The readings obtained from drop cables and motor leads should
be within the range specified in FIGURE 5. Low readings
indicate that the motor windings are grounded or that the cable
or splice insulation is damaged. If low or marginal readings are
obtained on a new installation the problem should be corrected
before proceeding with the installation.
Failure to turn off the power will damage the meter and can cause
serious or fatal shock.
Failure to disconnect the leads can result in false readings.
Set the meter selector knob to RX 100K or RX 100,000. (Some
meters may not have RX 100K in which case RX 10K or RX
10,000 scale can be used.) Clip the meter leads together and
adjust the meter to zero.
Unclip the leads and attach them. See FIGURE 4.
OHMS
ZERO
OHMS
OHMS
ZERO
OHMS
DROP CABLE
OR
MOTOR LEADS
DROP CABLE
OR
MOTOR LEADS
SINGLE PHASE, 2 WIRE - MEASURE BETWEEN TWO WIRES
SINGLE PHASE, 3 WIRE - MEASURE BETWEEN BLACK AND
THREE PHASE - MEASURE BETWEEN EACH PAIR, AB, AC
YELLOW AND THE MEASURE
BETWEEN RED AND YELLOW
GROUND
SET SELECTOR
KNOB AT
R x 100K
SET SELECTOR
KNOB AT R x 1
R x 100K
R x 1
R x 10
R x 100
R x 1000
R x 10K
10
20
25
5
2
0
R x 100K
R x 1
R x 10
R x 100
R x 1000
R x 10K
FIGURE 4 – Measuring Insulation Resistance
