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Block 5 - Fixed Generators And System Components > Objective: 1a > Flashcards

Objective: 1a Flashcards

0
Q

The magnetic field can be created with either _____ _____, or more commonly, _____.

A

Permanent Magnets,

Electromagnets

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1
Q

The rotor portion of the alternator assembly provides what?

A

Provides the main rotating magnetic field, one requirement of magnetic induction

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2
Q

Where are the field coils found and what do they need to retain in a self-excited system?

A

The field coils are found in the Exciter. The exciter needs to retain a Residual Magnetism in the self-excited system.

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3
Q

What sets the reference voltage in a voltage regulator?

A

Voltage adjust control

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4
Q

What is the purpose of the ATS (Automatic Transfer Switch)?

A

To furnish an alternate source of power to mission critical facilities where a loss of power may result in mission failure.

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5
Q

What do you need to do for manual operation of the ATS (Automatic Transfer Switch)?

A

Use the two manual handles and using the following procedures:
1. Open the cabinet door of the Transfer switch.
2. Place the motor disconnect switch (S1) to the “OFF” position.
3. Transfer to emergency
a. Pull upper manual handle down.
b. Push lower manual handle down.
4. Retransfer to normal
a. Pull lower manual handle up.
b. Push upper manual handle up.

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6
Q

What is stationary in the alternator?

A

Stator

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7
Q

How many voltage values are in a Wye connection?

A

There are 2 voltage values; Phase Voltage and Line Voltage.

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8
Q

A Wye connection is connected in _____?

A

parallel

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9
Q

A Delta connection is connected in _____?

A

series

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10
Q

What form transfers with the generator if it is moved to a different location/base?

A

AF Form 719

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11
Q

What are the three requirements for AC generation?

A

(1) Magnetic Field
(2) A conductor
(3) Relative motion between the conductor and field

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12
Q

These requirements fall under the Principle of what?

A

Magnetic Induction

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13
Q

Transformers use the Principle of what?

A

Mutual Induction

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14
Q

Current transformers can be step up or step down? TRUE OR FALSE?

A

False, Potential Transformer is a step up or step down.

The Current Transformer is always a step down, so voltage is dangerously high

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15
Q

Potential transformers can be step up or step down? TRUE OR FALSE?

A

True, the Potential Transformer is a step up or step down

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16
Q

What types of transformers are used for the AC AMMETER?

A

Current Transformer

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17
Q

What types of transformers are used for the AC VOLTMETER?

A

Potential Transformer

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18
Q

What does the WATTMETER indicate?

A

True Power load in an AC circuit

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19
Q

What does the Power Factor meter indicate? (it indicates two things)

A

Purely Resistive Load and indicates the percentage of true power being used

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20
Q

What is APPARENT/TRUE/REACTIVE POWER?

A

APPARENT POWER – power produced at the Power Source, which is the Generator.
TRUE POWER – consumed by the resistive load or loads.
REACTIVE POWER – power consumed by the reactive load devices in a circuit.

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21
Q

A three phase alternator has how many sets of windings and they are separated by how many degrees?

A

It has 3 windings in the Stator, the windings are positioned 120° from each other. 120° is the phase angle.

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22
Q

What is used with the AC Ammeter and Voltmeter to a change connections between phases?

A

Selector Switch

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23
Q

When is there no voltage present on the sine wave?

A

0°, 180°, and 360°

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24
Q

What is commonly referred to as the DC generator?

A

Exciter

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25
Q

What provides relative motion?

A

Prime Mover

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26
Q

What converts AC to DC in the alternator assembly?

A

6 Silicon Diodes and a Rectifier Circuit

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27
Q

What kind of voltage does the MPU create?

A

Pulsating AC

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28
Q

In order to initiate a test of the ATS, what must the RUN/STOP/REMOTE switch be in?

A

REMOTE

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29
Q

What is peak performance?

A

Voltage and Frequency

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30
Q

When is the highest operating temperature recorded on the AFCESA 487?

A

After 15 minutes

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31
Q

What switch is used to initiate a test on the ATS?

A

STOP SWITCH

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32
Q

What provides phase shift to drive linear motion?

A

Capacitor

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33
Q

How do you measure phase voltage?

A

Between any phase and the neutral.

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34
Q

How do you measure line voltage?

A

Between any two phases

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35
Q

On the ATS you must verify the settings have not been changed, the settings to check include: _____, _____, _____ and _____ _____.

A

Start Delay, Transfer Delay, Retransfer Delay, and Stop Delay

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36
Q

The solid-state panel delay settings can be adjusted by what?

A

Inserting a small screwdriver in the slot and rotating clockwise to increase the time delay or counter-clockwise to decrease the delay.

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37
Q

The _____ - load test is used to test all functions of a panel except the actual transfer of load.

A

with out

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38
Q

The _____ - load test will also test all functions, but will also include a load transfer.

A

with

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39
Q

When you perform a pre-optional inspection of the standby generator set. Ensure engine Control Switch is in the what?

A

“REMOTE” or “AUTOMATIC” position

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40
Q

Open ATS door, move the Test Mode switch to the “_____” position on the _____ _____ module.

A

“WITH OUT – LOAD”; Power Sentry

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41
Q

Close ATS door and _____ the _____ switch.

A

locate; test

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42
Q

Rotate the _____ / _____ / _____ switch to the “_____”.

A

Test / Normal / Retransfer ; “Test Position”

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43
Q

After brief delay (_____), generator starts.

A

(3 – 5 seconds)

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44
Q

After observation of LEDs on Power Sentry, while turning the switch to the “Test” position what happens next?

A

The Source 1 LED will go out. After a short delay, the Start Gen Set LED will come on and the generator will start.

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45
Q

Once generator has started and its _____ and _____ are within limits, Source 2 LED will illuminate.

A

voltage and frequency

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46
Q

After the transfer timing LED illuminates the time delay setting is met at which time the transfer complete LED comes on indicating what?

A

Indicating a transfer signal would have been sent to the transfer motor.

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47
Q

After test, return the _____ / _____ / _____ switch to the “_____”position.

A

Test / Normal / Retransfer; “Normal”

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48
Q

ATS will monitor what?

A

ATS monitors Source 1 for proper voltage and frequency

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49
Q

The battery charger should be operating at a low _____ _____ with a battery that is fully charged.

A

charging rate

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50
Q

Many charges are equipped with an “_____” switch and protected by a _____.

A

“ON / OFF” ; fuse

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51
Q

What is housed in the stator?

A

Stationary conductors of the alternator

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52
Q

What are the conductors also referred to as?

A

Stator windings

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53
Q

The stator can be constructed to provide _____ or _____.

A

Single Phase or Three Phase

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54
Q

What degree are the windings in three phase?

A

120°

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55
Q

Damper windings combat voltage fluctuation caused by what?

A

The rotor speed

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56
Q

What slows down the rotor?

A

Damper windings magnetic field by adding counter-torque to the stator

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57
Q

What happens when the rotor tries to slow down?

A

The Damper Windings magnetic field shift to add to the torque of the rotor field

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58
Q

Rotating rectifier circuits change AC to DC by use of what?

A

Six Diodes

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59
Q

What type of rectifier is the six diodes connected to?

A

Full-wave rectifier

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60
Q

What is an exciter often referred to as?

A

DC Generator

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61
Q

How is the varistor connected with the rectifier output?

A

In parallel with the rectifier output

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62
Q

What does a surge suppressor suppress?

A

Peak voltage surges

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63
Q

How does a varistor suppress volts?

A

Decrease its resistance and conduct more current through itself, suppressing the voltage surge

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64
Q

Variator and Surge Supressor are what?

A

The same thing

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65
Q

What provides the mechanical energy (torque) to turn the alternator rotor shaft?

A

Prime Mover

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66
Q

What begins to produce AC Voltage when the prime mover turns?

A

Exciter

67
Q

What senses the voltage at the output terminal of the stators?

A

Voltage Regulator

68
Q

What senses the voltage at the output terminal of the stators?

A

Amount of current flowing through the exciter field coils

69
Q

What is the purpose of an Exciter?

A

Provide a constant source of Direct Current to energize the alternators magnetic field

70
Q

What are the components of the Exciter?

A

Field Housing, Armature, and Rectifier Circuit

71
Q

What are the brushes used for?

A

Provides the electrical connection between the rotating component

72
Q

What are the brushes made of?

A

Soft carbon

73
Q

What is the FIRST step when inspecting an alternators components?

A

Make sure the unit is off-line and disconnect from any other power source.

74
Q

What is the LAST step when inspecting an alternators components?

A

Make sure residual voltage in the rotor, stator and exciter is discharged.

75
Q

What is the FIRST step when inspecting a rotating rectifier?

A

Remove the diode lead, this step will require the lead to be de-soldered from the diode.

76
Q

When inspecting a rotating rectifier, what is the LAST step?

A

Re-install serviceable diodes by positioning diodes on the heat-sink, secure, re-solder, and replace.

77
Q

What is the first step in inspecting a surge suppressor?

A

Remove exciter end cover

78
Q

What is the last step when inspecting a surge suppressor?

A

Observe the resistance value

79
Q

What resistance value should the varistor have?

A

15,000 ohms or greater

80
Q

An alternator converts _____ energy into _____ energy using the principle of magnetic induction to produce voltage.

A

mechanical ; electrical

81
Q

The exciter assembly is inspected for what conditions?

A

Inspect exciter assembly for missing or broken hardware

82
Q

What must a replacement diode have to be considered compatible?

A

Must have the same electrical rating as the original to be compatible

83
Q

How is the lead removed from the diode terminal?

A

Soldering iron, de-solder and remove

84
Q

How is the diode secured to the heat sink during installation?

A

Attach a nut

85
Q

What type of meter is used to test diodes?

A

ohmmeter

86
Q

What does a low reading in a diode mean?

A

The diode has a short

87
Q

What does a high reading in a diode mean?

A

open or O.L.

88
Q

What is used to check the insulation resistance of the generator’s main stator winding?

A

Megometer

89
Q

The rotor portion of the alternator assembly provides what?

A

Provides the main rotation magnetic field, one requirement of magnetic induction

90
Q

The magnetic field can be created with either _____ _____, or more commonly _____.

A

Permanent magnets ; electromagnets

91
Q

An electromagnet is what?

A

A coil of wire wrapped around a core material

92
Q

What is the purpose of alternators?

A

Converts mechanical energy to electrical energy

93
Q

What principle do alternators use?

A

The principle of Magnetic Induction: to produce voltage

94
Q

What portion of the alternator assembly provides the main rotating magnetic field, which is a requirement of magnetic induction?

A

rotor

95
Q

What is commonly referred to as a DC generator?

A

exciter

96
Q

In the event the rotor tries to slow down, the ____ _____ magnetic field shifts to add to the torque of the rotor field, keeping rotor speed.

A

Damper windings

97
Q

What controls the amount of voltage when using induction?

A

Strength of the magnetic field, number of conductors cutting the field and the speed of relative motion

98
Q

What is true power?

A

Power consumed by the resistive load

99
Q

What is apparent power?

A

Power produced at the power source

100
Q

What is reactive power?

A

Power consumed by the reactive load devices

101
Q

What is factor power?

A

The percentage of apparent power being used as true power by way of the resistive loan in an AC circuit.

102
Q

What are the types of connection for an alternator?

A

Delta (series) and Wye or Star (parallel)

103
Q

What is DELTA connection used for?

A

Industrial loads

104
Q

What is WYE connection used for?

A

For low power circuits

105
Q

What portion of the alternator provides the main rotating magnetic field?

A

rotor

106
Q

What kind of magnets does the rotor have?

A

Permanent magnet and electromagnets

107
Q

What is the common type magnet?

A

Electromagnets

108
Q

How many magnetic poles can an alternator rotor have?

A

Two, four, six or more magnetic poles

109
Q

What are some common examples of prime movers?

A

Gas or diesel engines, turbine engines, waterwheels, windmills, etc.

110
Q

A serviceable varistor will have a resistance value of ____ ohms or greater.

A

15,000

111
Q

Rotating rectifier circuits change AC to DC by the use of ____ ____ .

A

Six silicon diodes. The three-phase AC output of the rotating armature is rectified to DC by the use of six silicon diodes.

112
Q

What is housed in the stator?

A

The stator houses the stationary conductors.

113
Q

What makes up 1 magnetic field?

A

North and South Pole

114
Q

What sets the reference voltage in the control unit of the electronic governor?

A

The frequency-adjusting rheostat

115
Q

How do you initiate a test in the ATS (Automatic Transfer Switch)?

A

Turn off the S1 switch

116
Q

What are the 3 inspections within a pre-operational inspection?

A

Safety, Equipment, and Pre-operational setup of controls

117
Q

What form is maintained for life of the unit?

A

AF Form 719

118
Q

Where would you put a continuation of remarks on an AFCESA 487?

A

back of form in the comments/remarks section

119
Q

Why would you not disconnect the secondary of a current transformer if it is energized?

A

you don’t break connections when there is current

120
Q

Anything to do with wiring we check for? Anything to do with connections we check for?

A

(C.D.O.F.) Cracks, Deterioration, Over-heating, Fraying ; Security, Corrosion

121
Q

What prevents both contacts from being closed at the same time in an ATS?

A

Mechanical Interlock

122
Q

Who files the AFCESA 487 after it has been accomplished?

A

supervisor

123
Q

What five conditions is there, that would start the transfer of power in the ATS?

A
  1. Over voltage
  2. Under voltage
  3. Over speed/ frequency
  4. Under speed/ frequency
  5. Complete power loss
124
Q

What are the different time delays in an ATS and what are they for?

A

Start- allows the generator to warm up
Transfer- switches power source to generator
Re-Transfer - allows original power source to warm up
Stop - engine cool down

125
Q

If a battery charger is installed you inspect for it to be operable it should be charging at a ______.

A

low rate

126
Q

What does a Frequency meter indicate?

A

the number of cycles per second that are being completed

127
Q

The AC Voltmeter indicates what type of AC Voltage?

A

Effective Voltage

128
Q

The number of turns is referred to as the _____.

A

turn ratio

129
Q

If there are more windings or turns in the primary of a potential transformer and less in the secondary, then this is what type of potential transformer?

A

step down

130
Q

What is the purpose of the Alternator? (two answers)

A

Converts mechanical energy into electrical energy
Produces Alternating Current (AC)

131
Q

Speed is directly proportional to what?

A

frequency

132
Q

What must be removed first with all inspections dealing with the exciter?

A

disconnect batteries to prevent accidental starting

133
Q

Mechanical rectification utilizes what?

A

brushes and seal rings

134
Q

Brushless exciters use what to convert AC to DC?

A

rectifier

135
Q

What provides full load current to the customer?

A

stator windings

136
Q

What combats voltage fluctuations?

A

damper windings

137
Q

How do you test a diode and what indicates a good or bad diode?

A

ohmmeter
High resistance in both directions the rectifier is open - bad diode
Low resistance in both directions the rectifier is short - bad diode
High resistance and Low resistance in both directions of the rectifier is closed - good diode

138
Q

How do you replace a diode?

A

a. De-solder connection leads
b. remove the nut
c. lift diode from the heat sink
d. Reinstall serviceable diodes by positioning diodes on the heat sink, securing attaching nuts, and resoldering diode leads. Replace unserviceable diodes.

139
Q

How do you test a fuse in an energized circuit and what indication on the multimeter if bad/satisfactory?

A

a. Set the meter for volts AC/DC depending on circuit voltage
b. Measure across the fuse
c. Measure with voltmeter checking for a difference of potential (what goes in one side of the wire, should come out the other side
If the voltmeter shows any kind of number that is bad
0 volts = satisfactory

140
Q

When inspecting alternator components, what items MUST be discharged?

A

residual batteries, capacitors, and windings

141
Q

What are the five contaminants that can affect the insulation material of your windings?

A
  1. Dirt
  2. Salt
  3. Grease
  4. Oil film
  5. Moisture should not be allowed to accumulate on the windings
142
Q

When do you record the reading in a 30/60 time resistance test?

A

Record the 60-second reading

143
Q

What is a speed sensitive device used to regulate the engine speed from idle to maximum rated full-load speed?

A

electronic governor

144
Q

Define Isochronus or Zero Droop

A

allows the engine to remain at constant speed, regardless of load charges, for a single or paralleled unit.

145
Q

Define Droop

A

change in speed with a change in load

146
Q

When replacing a control unit, what adjustments must be made?

A

intial adjustments and final adjustments

147
Q

What is the special inspection item when dealing with the governor actuator?

A

linkage for freedom of movement

148
Q

What is the special inspection item when dealing with the voltage regulator?

A

vibration isolation dampers
Inspect for cleanliness

149
Q

When replacing an MPU, how many turns must you back it off once it has touched the top of the flywheel tooth?

A

one

150
Q

What repositions the fuel rack accordingly?

A

actuator

151
Q

What are the input and output connections on the control unit?

A

Magnetic Pickup
DC battery

152
Q

What is the first thing you do if there is a malfunction of the generator?

A

move the start switch to the “STOP” position

153
Q

If all else fails, one could cut off the air supply. How is this done?

A

clipboard, rags, in the air intake. anything but your hand

154
Q

If load increases, what will happen to your voltage being created at the MPU? Would a higher or lower output voltage be given to the governor actuator in order to regulate the speed?

A

actuator voltage remains at a higher level

155
Q

What do each of the indicator lamps on the ATS cabinet door represent in regards to what is happening within the ATS?

A

tells you how the load is connected
tells you what’s connected (Emergency or Commercial)

156
Q

What is the brain component of the ATS?

A

Power Sentry Control

157
Q

Why do we need to test our indicator lamps on our control panel of the generator?

A

incase there is a fault and the indicator lamps go on.
If there is a fault the indicator lamps will go on

158
Q

What switch is used to initiate a test on the ATS?

A

RUN/STOP/REMOTE SWITCH

159
Q

What does the with-load test switch test?

A

it test all functions, but will also include a load transfer

160
Q

2 wire/ 3 wire… what’s the difference?

A

2 wire - water
3 wire - air

161
Q

What makes or breaks current flow in your ATS?

A

contact assemblies

162
Q

What five conditions is there, that would start the transfer of power in the ATS?

A
  1. Over voltage
  2. Under voltage
  3. Over speed
  4. Under speed
  5. Complete power loss
163
Q

What position should the S1 Motor Disconnect Switch be in after manual operation?

A

“Automatic” position

164
Q

What do you look for with the values given to indicate whether or not to use a three phase formula or a single phase formula?

A

Amperage (3 amperage values for a 3 phase; 1 for a single phase)

Block 5 - Fixed Generators And System Components (1 decks)

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