Jet Power FILTER II User manual

OPERATION AND
MAINTENANCE MANUAL
PN 28.04.1014
SUPERSOM IND. E COM. LTD.
GROUND POWER UNIT - GPU
OUTPUT OF 28 VDC AND 24 VDC
SPECIAL EDITION FOR AIRCRAFT
MANUFACTURER
JET POWER FILTER II - PN 28.09.1013

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Sumário
1 - DESCRIPTION................................................................................................................................4
1.1 - GENERAL...................................................................................................................................4
1.1.1 - PRESENTATION.................................................................................................................4
1.1.2 - TECHNICAL INFORMATION...............................................................................................5
1.2 - SPECIFICATIONS........................................................................................................................7
1.2.1 - OUTPUT CABLES AND TRANSFORMER.............................................................................7
1.2.2 - CONTROL PANEL (UPPER PANEL).....................................................................................8
1.2.3 - LOWER PANEL ............................................................................................................... 10
1.2.4 - FRONT PANEL ................................................................................................................ 11
1.2.5 - SIDES.............................................................................................................................. 11
1.2.6 - UPPER PART................................................................................................................... 12
1.2.7 - LOWER PART ................................................................................................................. 12
1.2.8 - NOTES............................................................................................................................ 12
2 - OPERATION ............................................................................................................................... 13
2.1 - GENERAL................................................................................................................................ 13
2.1.1 - SUPPLYING FOR AN AIRCRAFT IN ASSEMBLING............................................................ 13
2.1.2 - TESTING AND ADUJSTING THE SURGE PROTECTOR RELAY IN OUTPUT SOURCE SOCKET
14
2.1.3 - OPERATION AND FUNCTIONING................................................................................... 15
3 - THEORY OF OPERATION ............................................................................................................ 16
3.1 - POWER GENERATION SYSTEM .............................................................................................. 16
3.2 - OPERATION DESCRIPTION..................................................................................................... 16
4 - TROUBLESHOOTING .................................................................................................................. 17
4.1 - NOTES.................................................................................................................................... 17
4.1.1 - POSSIBLE FAULTS........................................................................................................... 17
5 - INSPECTIONS, VERIFICATIONS AND LUBRICATIONS.................................................................. 21
6 - REMOVAL AND INSTALATION ................................................................................................... 22
6.1 - REMOVAL .............................................................................................................................. 22
6.2 - INSTALLATION ....................................................................................................................... 22
7 - ADJUSTS AND TESTS.................................................................................................................. 24
7.1 - ADJUSTMENT OF THE CURRENT LIMITING ........................................................................... 24
7.2 - ADJUSTMENT OF THE TENSION LIMITING ............................................................................ 24
7.3 - ADJUSTMENT OF THE OUTPUT TENSION.............................................................................. 24
7.4 - ADJUSTMENT OF THE CURRENT LIMITING ........................................................................... 24

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7.5 - CALIBRATE THE INSTRUMENTS ............................................................................................. 25
7.6 - RIPPLE TEST ........................................................................................................................... 25
7.7 - OUTPUT TENSION TEST ......................................................................................................... 25
7.8 - ADJUSTMENT OF THE DIFFERENTIATOR CIRCUIT ................................................................. 26
8 - CLEANING AND PAINTING......................................................................................................... 26
8.1 - CLEANING.............................................................................................................................. 27
8.2 - PAINTING............................................................................................................................... 27
9 - REPAIRS ..................................................................................................................................... 28
10 - LIST OF GENERAL PARTS............................................................................................................ 29
11 - DESCRIPTION............................................................................................................................. 30
11.1 - PRESENTATION.................................................................................................................. 30
11.2 - CIRCUIT OF ELECTRONIC PROTECTION II (PN 28.01.1018)................................................ 30
11.3 - CIRCUIT OF ELECTRONIC PROTECTION III (PN 28.00.3717)............................................... 31
11.4 - POWER CIRCUIT (PRIMARY) .............................................................................................. 31
11.5 - POWER CIRCUIT (SECONDARY) ......................................................................................... 33
11.6 - DIFFERENTIATOR CIRCUIT (PN 28.01.7000) ...................................................................... 36
12 - SPECIAL TOOLS, ADAPTERS AND EQUIPMENTS ........................................................................ 36
12.1 - SPECIAL KEY TO WITHDRAWAL DIODES (PN 28.01.1191)................................................. 36
12.2 - SUPPORT TO HOIST THE EQUIPMENT (PN 28.01.1192).................................................... 36
12.3 - SOURCE OF 0-60mV FOR CALIBRATION OF THE PROTECTION CIRCUIT (PN 28.01.1193). 36
13 - GALLERY OF PHOTOS................................................................................................................. 38
13.1 - DIFFERENTIATOR CIRCUIT ................................................................................................. 38
13.2 - LINKING OF THE AJUSTMENT SWITCH OF 7 POSITIONS.................................................... 39
13.3 - KNOBS LINKING ................................................................................................................. 40
13.4 - SECONDARY CIRCUIT......................................................................................................... 40
13.5 - LINKING OF THE INPUT CABLE........................................................................................... 40
13.6 - PANEL OF INSTRUMENTS .................................................................................................. 41
13.7 - IDENTIFICATION PLATE...................................................................................................... 41
13.8 - BLOCK OF CONNECTORS OF THE DIFFERENTIATOR CIRCUIT ............................................ 42

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1 - DESCRIPTION
1.1 - GENERAL
1.1.1 - PRESENTATION
The “JET-POWER FILTER II” is a static GPU designed to provide
ground power for maintenance and startup of aircraft having 28 VDC
electrical systems.
The “JET-POWER FILTER II” changes alternating current at its input
to a continuous current of 28V (adjustable on panel) by using its trans-
former and six-phase rectification. Therefore when electric energy is
available to supply the GPU it can substitutes external batteries or/and
GPU equipped with diesel engine.
The “JET-POWER FILTER II” provides pure output tension with ex-
tremely low ripple (0.035% at 100A), even under normal load, causing
no interference with aircraft equipments.
Due to its transformer and oversized rectifier the regulation is excellent
and provides protection against short circuit, over current, overvoltage
and phase failure.
The “JET-POWER FILTER II” has been resized especially for
MANUFACTURER to be used in extreme conditions (24 hours work-
ing) providing power to mounting equipments on an aircraft during
stages of assembly and electronics testing.
It is equipped with a second output cable of 28 and 24 VDC,to substitute
aircraft´s battery, being able to reduce 09 volts on its output voltage rel-
ative to the first output by setting its selector switch on position “7”.

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1.1.2 - TECHNICAL INFORMATION
1.1.2.1 - INPUT:
220V (Brazil);
208V (USA);
Three-phase, no phase sequence.
NOTE: The neutral of “JET-POWER FILTER II” is the BLUE cable.
1.1.2.2 - 1st OUTPUT (Plug for Output Source)
It is located on the left front side, coming directly from inside the source,
providing 24 to 33 VDC, depending on how the seven position switch
(front panel) is set.
1.1.2.3 - 2nd e 3rd OUTPUT (28 and 24V to substitute aircraft´s battery)
They are two gray connectors, placed at the front center, to be used with
one cable, connected on the left to provide tension and current equal to
the first output (28 V), or connected on the right to provide 09 volts less
than the first output. When giving 33 volts it will provide 24 volts (up
to 10A, protects against overload). The cable to be connected to these
outputs is loose, with a gray connector, with length as ordered (5 or 10
m). In order to avoid accidental disconnection lock it by using the at-
tached pin.
1.1.2.4 - MAXIMUM CURRENT:
2,000A at peak (supply capacity);
600A continuous (28V output).
NOTE: The current delivered by “JET-POWER FILTER II” at the start,
or during equipment tests, depends on the turbine kind or the applied
load.
1.1.2.5 - CURRENT LIMITER

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The current can be limited to 30, 50, 100, 200, 300, 400, 500, 750,
1000, 1500 e 2000A.
NOTE: The “JET-POWER FILTER II” is equipped with an electronic
circuit adjustable up to 11 positions. It turns off the source when the
current set at knob is reached.
1.1.2.6 - MAXIMUM POWER
56kVA at peak with full load.
NOTE: The Power required from installation can be much lower if not
using maximum current.
EXAMPLE: With load up to 1200A in the output, the power necessary
will be 37kVA maximum at peak. The rated power of the network
should be above 25kVA.
1.1.2.7 - AUTOMATIC PROTECTION (for the aircraft)
It automaticallyshuts down the equipment in case ofphase failure, over-
voltage or over current (above the settled value), in order to minimize
risks to the aircraft and GPU.
1.1.2.8 - RIPPLE
0,59% at 300A (28V output);
With load from 0 to 100A, only 0.01 VAC - Ripple 0,035%.
1.1.2.9 - DIMENSIONS
111.5 cm (length) x 85 cm (width) x 88.5 cm (height).
1.1.2.10 - WEIGHT
528 Lbs.

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1.2 - SPECIFICATIONS
1.2.1 - OUTPUT CABLES AND TRANSFORMER
1.2.1.1 - INPUT CABLE (PN 28.01.1146)
The cable is quadripolar, brand “Prysmian”, model CORDPLAST, 4 x
10 mm2of gauge, 25 meters of length. It does not come with a plug (the
plug can vary according to the local utility company).
1.2.1.2 - 1st OUTPUT CABLE 28VCD, direct plug (PN 28.01.3340)
The normal output cable line is double, extra flexible, 95 mm2of gauge,
5 meters of length, equipped with anti-friction protection and output
socket; brand “SUPERSOM”(PN 28.01.1139).
1.2.1.3 - 2nd OUTPUT CABLE 28 and 24 VCD, gray connector (PN
28.01.4705 with 5 meters and PN 28.01.4710 with 10 meters)
This is a brand new model of cable, all detachable, equipped with anti-
friction. It comes with 5 or 10 meters of length (as ordered), double
gauge of 70 mm2, in one end it comes with a gray connector and in the
other end it comes with a rubber plug , 28V standard, brand
“SUPERSOM”(PN 28.01.1139). Must be used to substitute the battery,
can be attached to the 28VDC connector of high current or to the distin-
guish output connector (24 VDC).
1.2.1.4 - TRANSFORMER (208V/220V –PN 28.01.1103)
It is designed to deliver alternated current of low voltage to the
rectifier circuit;
Comes with 09 output connections (six-phase), resulting in
28VDC after rectification;
It has 27 input wires to provide a voltage adjustment at the equip-
ment input.
NOTE: It can be used in 208 or 220V by only switching cables plugged
into the fuse holder. These cables are marked according to its voltage

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(208 or 220V). They cannot be plugged together; it could cause a short
circuit. To plug in one cable the other must be removed and isolated.
The three cables must have the same voltage (208V USA or 220V Bra-
zil).
Power : 56 kVA at peak;
Maximum output current: 2,000 A;
5 seconds off peak with voltage drop of 20%.
1.2.2 - CONTROL PANEL (UPPER PANEL)
1.2.2.1 - SWITCH FOR ADJUSTMENT OF THE OUTPUT TENSION
(PN 28.01.1150)
It sets the output tension from 24 to 33VDC.
1.2.2.2 - SWITCH FOR ADJUSTMENT OF THE OUTPUT CURRENT
LIMITER (PN 28.01.1122)
Placed on the right side of the panel, it must be used to set the maximum
current allowed on the aircraft in which it is connected. The accuracy
of this setting is around 5%.
The current limit is taken by a complete disconnection of the output
current after 1 second exceeding the set value.
Never place the current limiter knob in range below that demanded by
the load necessary for maintenance or during starts to avoid cuts during
the maintenance or at the start. Please check the aircraft manual to know
about its maximum current demanded.
ATTENTION:
The setting above the maximum current range allowed by the aircraft
does not mean that the current will come to this value in normal condi-
tions, even at the start.
Under normal conditions the GPU will deliver only the current de-
manded by the aircraft.

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1.2.2.3 - SWITCH ON/OFF (Level 1 and 2) - AUTOMATIC
PROTECTION (PN 28.01.1121)
It´s function is to permit the use of the equipment in case off breakdown
at the protection circuit or release the use with voltages over 31.5 VDC.
With the switch set on position “1” it could be used normally but there
will be no automatic turning down.
1.2.2.4 - KNOB “ON” (PN 28.01.1119) AND “OFF” (PN 28.01.1120)
They turn the equipment on and off. The turning off knob can also
RESET the protection circuit.
When the equipment is shut down by the protection circuit the turning
off knob must be used to restart. Otherwise the equipment will not turn
on.
1.2.2.5 - LED INDICATOR OF EQUIPAMENT “ON”: (PN 28.01.1124)
It is placed between the knobs. When the equipment is shut down by the
protection circuit it will turn off and the protection circuit will remain
turned on to indicate what caused the shutting down.
1.2.2.6 - BURNED FUSES INDICATORS (PN 28.01.1124)
When lighted it indicates burned or loosen fuse(s). The fuses are located
inside the front cover, closed to the three-phase cable entrance. To open
the front cover, unscrew the two screws on its sides.
1.2.2.7 - INDICATORS OF AUTOMATIC SHUT DOWN (PN 28.01.1126)
The three red light indicators inform the operator the cause of shutting
down when occurs one or more of the following:
Phase failure at the input power;
Overvoltage and over current at the equipment output.
They are monitored by the “Protection Circuits II and III”.

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1.2.2.8 - INDICATORS OF PHASE PRESENCE (PN 28.01.1125)
Three Green LEDs –they light only when the GPU is turned on.
If one of them is out it indicate phase failure. Before using the GPU
verify and fix what caused the phase failure. If used with one phase out,
it will be notice a high drop of voltage, increasing the load. The output
voltage will drop to around 21V with only 50A of load causing high
current at the capacitors. These LEDs are monitored by the “Protection
Circuit III”.
1.2.2.9 - VOLTIMETER (PN 28.01.1127)
Indicates the 28V outputs voltage, where the output cables are con-
nected.
During start peak the voltage at the aircraft will be lower than indicated
on this voltmeter due to voltage drop at the output cables and the internal
aircraft cables.
1.2.2.10 - AMMETER: (PN 28.01.1128)
Indicates the current provided to the aircraft (the sum of the currents in
the two output cables).
60mV instrument, coil, 2000A scale.
1.2.3 - LOWER PANEL
1.2.3.1 - IDENTIFICATION PLATE (PN 28.02.1216)
It indicates three-phase input voltage, range of output voltage (adjusta-
ble), maximum peak current, serial number, equipment´s part number,
weight and dimensions.

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1.2.3.2 - INPUT CABLE (see item 1.2.1)
Placed on the bottom left of the front cover. It comes with 25m of length
(it can be ordered with other lengths). Normally brand “PRYSMIAN”,
CORDPLAST type, 4x10mm2of gauge.
The neutral is connected internally to the BLUE cable.
After some years of use this cable may break close to the passage rubber,
internally, due to a great number of flexions. This could cause phase or
neutral failure. If that occurs cut the cable close to the entrance and re-
connect.
1.2.4 - FRONT PANEL
1.2.4.1 - VENTILATION GRID
Provides the exit of heated air pulled out by internal fans.
NOTE: The grid must never be blocked.
1.2.4.2 - OUTPUT CABLES (see item 1.2.1)
The socket for the aircraft´s output source (28V) is located on the left
side.
At the Center are placed the output connector to substitute the battery
(28V) and the differentiated output of less 9V (24V).
1.2.5 - SIDES
1.2.5.1 - HOOKS TO HOLD CABLES
It comes with hooks on both sides to hank the input cable on one side
and the output cables on the other side.
To prevent damage to the equipment avoid collisions with the hooks
while moving it.

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1.2.5.2 - VENTILATION GRID
It has four (04) lines of shutters for internal ventilation.
Do not use plastics covers that seal. They are placed to prevent the entry
of water or rain splashes.
1.2.6 - UPPER PART
1.2.3.1 FRONT AND COVER
To open the GPU unscrew first the two screws (one in each side of the
panel) and use the handle. To release the top cover, unscrew the screws
on the bottom side and lift the cover. The cover is heavy and may be
necessary more than one people to raise it.
It has a gutter under the spotlight to avoid rain water.
1.2.7 - LOWER PART
1.2.7.1 - CASTERS
Comes with 02 (two) fixed casters (PN 28.02.1203) and 02 (two) swivel
(PN 28.02.1203), with 6” wheel, brand “NOVEX”, of high durability.
1.2.7.2 - CHASSIS (PN 28.02.4201)
The chassis is perfectly dimensioned for the weight to be supported. It
has reduced weight and high mechanical resistance.
1.2.8 - NOTES
All pieces are manufactured following standard equality. They may be
replaced at any time without the need for adjustments in drilling, etc.

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2 - OPERATION
2.1 - GENERAL
2.1.1 - SUPPLYING FOR AN AIRCRAFT IN ASSEMBLING
a) Connect the extension into the socket and take it near the JET POWER (if
an extension is needed).
b) Place the “JET POWER” near the input socket for external power source
of the aircraft.
c) Connect the output socket of the cable coming out of the left side of the
“JET-POWER” into the aircraft output source socket.
d) Connect the output socket that comes out of the connectors at the center of
the “JET-POWER” on the adapter that replaces the battery. Place the cable
connector on the 28 VDC position.
e) Connect the input socket.
f) After connecting, check the lightening of the three phase indicators. Do not
use if any is out. When using the automatic protection it will not turn on.
With the automatic protection off it will accept to turn on, but it is highly
not recommended.
g) Adjust the knob of the current limiter into the limit above the maximum
current allowed on the aircraft connected.
h) Turn on the automatic protection switch (it should only be turned off in case
of malfunction at the protection circuit or if a voltage above 31.5 V is nec-
essary).
i) Before connecting check if the output voltage switch is in a position that
does not cause overvoltage automatic shutdown.
j) Turn on the equipment by pressing the left green knob. It should light a
signaler between the knobs and will be an indication of voltage and current,
if loaded. If the equipment shuts down automatically a red LED will light
to indicate the cause of the shutdown. To RESET the equipment push the
OFF knob and then turn it ON.

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NOTE: When everything is set simply use the ON and OFF knobs to con-
trol the “JET-POWER”.
k) Adjust the output voltage to around 28V for normal use during the mount-
ing of equipments or as the desired voltage. If the voltage set is above 31.5V
the equipment will shut down due to overvoltage. Reduce one position,
press the knobs OFF and then ON to RESET.
NOTE: After use the equipment must be turned off and disconnected from air-
craft.
2.1.2 - TESTING AND ADUJSTING THE SURGE PROTECTOR
RELAY IN OUTPUT SOURCE SOCKET
a) Do as shown in items A to C of the preceding instructions.
b) Disconnected the existing aircraft load so that only supply the surge pro-
tector relay.
c) Turn off the automatic protection switch.
d) Connect the output socket that comes out of the “JET-POWER” central
connector into the adapter that substitutes the battery. Place the output cable
connector at 24 VDC position (right side connector).
e) Check the lightening of the three phase indicators. Do not use if any is out.
When using the automatic protection it will not turn on. With the automatic
protection off it will accept to turn on, but it is highly not recommended.
f) Place the output voltage regulator switch at position 7 (output voltage
around 33 V).
g) Turn on the equipment by pressing the left green knob. In this position (7)
there will be a difference of 9 volts between the external source power sup-
ply and an external source which simulates the battery voltage, being able
to be used to adjust the aircraft surge protection relay.
h) After use the equipment must be turned off and disconnected from aircraft.
It must be removed from the output connector of 24 Volts and connected to
the 28 VDC output.

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2.1.3 - OPERATION AND FUNCTIONING
To operate the “JET-POWER” properly follow the steps outlined in the
previous section (2.1.1). When the equipment is all set simply use the
knobs ON and OFF to operate the GPU.
The operation of “JET-POWER” does not involve engines and genera-
tors being totally static and silent.
The “JET-POWER” transformer receives alternating current provided
from the local utility company and transforms it to low voltage contin-
uous current of high purity and high current capability.

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3 - THEORY OF OPERATION
3.1 - POWER GENERATION SYSTEM
The power generation system transforms the alternating current pro-
vided from the local utility company to six-phase alternating current
(low voltage) to be rectified and filtered.
3.2 - OPERATION DESCRIPTION
Its operation is completely static.
The transformer receives electricity from the local utility company,
transforms the three-phase energy of 220V or 380V in six-phase low
voltage to supply 28 V with high current capability.
The energy is rectified by six (06) diodes, filtered by a high capacity
filter and delivered to the aircraft after passing through over current,
overvoltage and phase failure sensors.

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4 - TROUBLESHOOTING
The following is a list of symptoms and possible causes that may disturb
the normal operation of your “JET-POWER”. Follow the instructions
properly to avoid problems in operating the equipment.
When an unconformity is detected follow the steps listed in the next
pages. If the problem persists, call our technical department and ask for
more detailed information or technical assistance.
4.1 - NOTES
Do not use “DIAZED” (retarded) fuses or wired bridge. Use “FAST”
or “ULTRA-FAST” fuses. In 208 or 220V, use 63A fuses.
Keep spare fuses (at least 06).
The “JET-POWER” uses 06 (six) SKR240/04 rectifier (brand
“Semikron”) for 28 VDC.
The “JET-POWER” uses 47000µF/40V capacitors (brand “Epcos”).
Avoid opening the “JET-POWER” unnecessarily.
4.1.1 - POSSIBLE FAULTS
A) When turning the equipment on, the voltmeter does not indicate volt-
age.
CAUSE: Instrument defective or power failure.
CHECK: If the equipment turns on, test the instrument. If not,
check the connecting to the local utility company.
B) Fuses burning immediately after power is turned on.
CAUSE: Internal or external short circuit.
CHECK: It is more likely that one or more rectifiers have been
short-circuited. To test them follow the instructions below:

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Test the secondary resistance. If it indicates 8.2 Ω it is normal. If
it is close to 0 Ω indicates short circuit in wires or diodes;
Open the front cover. Disconnect the plug from the panel light (if
equipped with this optional item) and remove the top cover;
Loosen the 06 terminals of the rectifiers;
Using a multimeter, test the rectifiers (one by one);
Replace the ones in short-circuit;
Use a pipe wrench with bolt hole to loosen the damaged rectifiers;
Use original rectifiers (brand “Semikron”);
Replace blown fuses and test the equipment before closing it;
When closing the device observe the flasher contact sides at the
top cover bottom.
C) The voltmeter continues to indicate voltage when turned off.
CAUSE: With the output socket connected, the voltmeter may be
indicating the aircraft battery voltage, or capacitors voltage, if the
resistor load is interrupted.
CHECK: Unplug the aircraft. The voltmeter should indicate zero, if
not, test the load resistor (8.2 Ω).
D) Voltage dropping below 22 volts at start peak.
CAUSE: Voltage drop on the local utility company (see note below).
CHECK: Measure the voltage at the output socket where the “JET-
POWER” is plugged in. With no load it should be indicating at least
205 V. Ask the pilot to start the turbine. Measure the voltage during
the current start peak. The voltage should drop below 185 V between
phases. If the voltage measured is between those limiters do as fol-
lowed:
Set the output voltage in 30/31VDC to start turbines. This small
increase compensates part of the loss on the network and im-
proves the start;
If the supply voltage is below the limits indicated above check the
installation.
NOTE: There are internal voltage drop at the “JET-POWER” and
losses at its output and input connectors. These losses were

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reduced to minimum through the super dimensioning of the
internal and external conductors.
E) Noise in aircraft communication radio.
CAUSE: Small ripple on the equipment output continuous current.
CHECK: Verify if the capacitor filter (47000uF) is open.
NOTE: The “JET-POWER” produces no noise on the radio or any
type of interference with aircraft navigation equipment.
However, this may occur in case of failure in the capacitor
filter.
oThe component of alternating current, with load up to
100A, is only of 10mV (0,01V), peak to peak. Ripple of
0.035% to 100A.
F) Electric shock in the equipment.
CAUSE: Leakage current from the local utility company to the
equipments chassis.
CHECK:
Wrong linking of the NEUTRAL cable;
NEUTRAL cable with no connection with the socket or
equipment;
NEUTRAL cable broken by the entrance plate or by the
fixing clamp.
NOTE: The NEUTRAL cable is BLUE.
G) Output differentiated with no voltage.
CAUSE: Open integrated circuits.
CHECK:

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Replace the two CI´s LM338K from the differentiator
circuit (To replacethen see the screwsthat must be loos-
ening at photo gallery. Use CI brand ST.)
H) Output differentiated with the same voltage as normal output.
CAUSE: Circuits integrated in short circuit.
CHECK:
Replace the two CI´s LM338K from the differentiator
circuit.
I) Output differentiated with voltage different of 9 Volts in relation to
the main output.
CAUSE: Incorrect adjustment of the potentiometer at the upper part
of the differentiator circuit.
CHECK: Output voltage adjustment as bellow:
Open the top cover;
Use a precision voltmeter at the positive terminal in the
positive output of 28VDC (left side connector) and the
negative terminal in the positive output of24VDC (right
side connector);
With the equipment ON, turn the 7 position switch to
position 7 with the automatic protection circuit OFF,
adjust the voltage to 9.0 Volts.