Electrical Testing - Lorentz PS200 Installation Operation & Maintenance

8.3

Electrical Testing

A "multimeter" is required and a clamp-on ammeter
is helpful. For advice, see section 13.8, Selecting and Using
Meters for Electrical Testing
Record your test results on the Problem Report
Form, "Test #" REFERS TO TABLES AND PHOTOS IN SEC-
TION 10
If you see a false reading of the SOURCE LOW or
TANK FULL light, go to tests # 9/10/11
Test the solar array circuit
1. Open-circuit voltage, cf. Test #1
voltage. It is normally high because no current is
being drawn (it's doing no work).
2. SHORT CIRCUIT CURRENT, cf. Test #2
test — This is helpful if the pump is trying to start
or does not seem to get full power. disconnect THE
ARRAY from the controller before making this test.
(A short circuit at the array will only cause current
slightly higher than normal.) If you don't have a DC
amp meter, a spark that can jump 1/4 in (6 mm)
indicates a good probability that the array is working
properly.
3. Voltage under load (with pump running), cf.
Test #3
4. Current under load, cf. Test #4
Was power was connected to the controller with reverse
polarity?
No lights will show on the controller. This will not
cause damage, cf. Test #1
Test the motor circuit (resistance test with POWER
OFF), cf. Test #7 Make this test if there is proper voltage
at the controller input but the motor does not run. It will
confirm the condition of the entire motor circuit, including
the motor, pump cable and splice.
Test the running current of the motor circuit (AC
amps), cf. Test #6/6A This is one of the most useful
trouble shooting techniques because it indicates the force
(torque) that the motor is applying to the pump. For great-
est ease, use a clamp-on ammeter, available from local
electrical equipment suppliers. It allows you to measure
current without breaking connections (cf. Test #6A).
Manual | LORENTZ PS Pump Systems
Table of AC RUNNING CURRENT For helical rotor
pumps, normal running current indicated on this table. The
current stays nearly constant as voltage and speed vary.
Your measurements may vary by as much as 10 %, and
more if temperature is out of the normal range. Comparing
your reading with this table. This will indicate whether the
work load on the motor is normal for the lift it is producing.
Make note of your measurement. Future changes may indi-
cate pump wear, or change in the level of the water source.
HIGHER CURRENT (especially PUMP OVERLOAD
light) may indicate:
This is "idle" 1. The pump may be handling excessive sediment
(sand, clay).
2. The total dynamic head (vertical lift plus pipe friction)
or spark may be higher than you think it is.
3. There may be an obstruction to the water flow —
sediment in the pipe, ice in the pipe, a crushed pipe
or a partially closed valve. (Is there a float valve at
the tank?)
4. Helical rotor models: Water may be warmer than
72 °F (22 °C). This causes the rubber stator to expand
and tighten against the rotor (temporarily, non-
damaging). See section 12 for temperature limits.
5. Helical rotor models: Pump may have run dry. Re-
move the pump stator (outer body) from the motor,
to reveal the rotor. If there is some rubber stuck to
the rotor, the pump end must be replaced.
To reset the OVERLOAD shutoff (red light), switch the
pump controller OFF and ON.
LOWER CURRENT may indicate:
1. In a deep well, the level of water in the source may
be far above the pump intake, so the actual lift is less
than you think. This is not a problem.
2. The pump head may be worn, thus easier to turn
than normal (especially if there is abrasive sediment).
3. There may be a leak in the pipe system, reducing the
pressure load.
4. Helical rotor models: Water may be colder than 46 °F
(8 °C). This causes the rubber stator to contract, away
from the rotor. The pump spins easier and produces
less flow under pressure.
Errors excepted and possible alterations without prior notice.
Test the low-water probe circuit If the controller
indicates "SOURCE LOW" when the pump is in the water,
the low-water probe system may be at fault. (See section
5.9.) The controller applies 5 V DC to the probe terminals.
When the water level is above the probe, the switch in the
probe makes contact. That causes the applied voltage to
drop toward zero. The systems "sees water" and allows the
pump to run. If the voltage is greater than 3 V, dry shutoff is
triggered, cf. Test #9
The low-water probe has an internal 1 kΩ resistor in series
with the switch. When closed (in water), the normal resist-
ance is around 1 kΩ.
To bypass the low-water probe (and activate the pump),
connect a small wire between the probe terminals (tests
#1 and #2) in the junction box. Restart the controller. If
the pump runs, there is a fault at the probe or in the probe
wiring. The wires may be shorted (touching each other)
or open (broken) or the moving part on the probe may be
stuck with debris, or the probe may be out of its normal,
vertical position.
Test the full-tank float switch If the controller
indicates "TANK FULL" when the tank is not full, the float
switch or pressure switch system may be at fault. See sec-
tions 5.10 or 5.12
1. If the remote switch circuit is NOT being used, there
must be a wire between terminals 4 and 5.
2. There are two types of float switch, "normally open"
and "normally closed". Check to see that the wiring
is correct for the type that is used.
3. Most float switches are "normally open". Disconnect
a wire from terminal 3 or 4, and the pump should
run. Connect a wire between terminal 3 and 4, and
the pump should stop. See also Test #10
4. Most pressure switches (and some float switches)
are "normally closed". Connect a wire between
terminals 4 and 5, and the pump should run. See
also Test #11
If the pump responds to the bypass tests above but not to
the float switch, the wires may be shorted (touching each
other) or open (broken), or the switch may be stuck with
debris, or out of its correct position.
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