If the three-phase motor, shown in the illustrated schematic diagram, is running in the forward direction, which of the following actions must occur before the motor will reverse rotation? EL-0011 A. Normally-closed contacts '4'-'5' must open. B. Normally- open contacts '2'-'3' must close. C. 'L1' and 'L3' must be interchanged via the 'R' contacts. D. All of the above.

1 Answer

Answer :

Answer: C

Related questions

Description : Refering to the illustrated schematic diagram, which of the following statements is true when the motor is running in the forward direction? EL-0011 A. Normally-open contacts '4-5' are closed. B. Current ... switch. C. Normally-closed contacts 'R' are open. D. The blowout coils must be closed.

Last Answer : Answer: B

Description : Regarding the illustrated electrical schematic, 'S1-P', 'S1-Q', and 'S1-R' represent ____________. EL-0016 A. capacitors B. normally-closed contacts C. normally-open contacts D. normally-closed pushbutton switches

Last Answer : Answer: C

Description : In the illustrated schematic diagram, which of the listed devices prevents the forward and reversing coils from being energized simultaneously? EL-0011 A. An 'either-or' interlock B. A mechanical interlock C. Blowout coils D. A stop button

Last Answer : Answer: A

Description : If the motor fails to start and a voltmeter reading between 1 and 6, as illustrated, indicates line voltage, your next step should be to ________. EL-0007 A. replace fuse '10a' B. replace or repair contact 'Ma' C. reset and determine the cause of the overload D. check line voltage between L1 and L3

Last Answer : Answer: C

Description : If fuse 'F-1' in the illustrated schematic diagram opens, ____________. EL-0017 A. the motor will run slowly B. 'A-1' and 'A-2' will open C. the motor will not start D. the start button will jam in the closed position

Last Answer : Answer: C

Description : The schematic diagram shown in the illustration uses symbol 'A' to represent a/an _________. EL-0011 A. non-renewable fuse link B. circuit breaker coil C. overload relay coil D. thermal overload heater

Last Answer : Answer: D

Description : If the illustrated motor fails to start and gives a loud hum when the start button is pushed, the problem is ________. EL-0007 A. one of the phases to the motor is not energized because of ... electrical distribution system D. 'OL1' is open because of 'T1' overload causing the motor to single phase

Last Answer : Answer: A

Description : When the motor shown in the illustration is running and the stop button is pushed, which of the following statements will hold true? EL-0010 A. Coil 'M' will now be energized. B. Coil 'CR' will now be energized. C. Contact 'M' will close as contact 'CR' opens. D. Contacts 'M' and 'CR' will open.

Last Answer : Answer: D

Description : When an operating motor is connected to the controller shown in the illustration, the a path of current flow through the circuit is ____________. EL-0010 A. 'L1', stop button, start button, coil 'CR', 'L2' B. 'L1' ... L2' D. 'L1', stop button, start button, 'CR' contact, 'M' contact, 'CR' coil, 'L2'

Last Answer : Answer: B

Description : The direction of rotation of the winch shown in the illustration is changed by reversing the _____________. EL-0102 A. direction of current through the shunt field B. polarity of voltage at 'S1' and 'S2' C. direction of current through the armature D. polarity of voltage at 'L1' and 'L2'

Last Answer : Answer: C

Description : The contacts operated by the D.C. relay coil shown in the illustration are located in the schematic diagram prints at coordinates ____________. EL-0100 A. '41Y' on this page B. '52M52M' and '52H35M' C. '57R' on this page D. '52N' on page '57R'

Last Answer : Answer: C

Description : As shown in the illustration, the symbol is used in electrical drawings to designate a ____________. EL-0026 A. limit switch with one set of normally open contacts B. maintaining type ... type push button with a mechanical interlock D. normally closed contact held open mechanically by an interlock

Last Answer : Answer: C

Description : 'A-1', as shown in the illustration, is/are ____________. EL-0017 A. normally-closed overload relay contacts B. a double pole knife switch C. normally-open overload relay contacts D. a single pole knife switch

Last Answer : Answer: A

Description : As shown in the illustration, which listed action will occur first when push button 'Q' is depressed? EL-0017 A. Contacts 'H-1', 'H-2' and 'H-3' close. B. Contact 'H-4' closes. C. Operating coil 'C' energizes. D. Switch 'R' opens.

Last Answer : Answer: C

Description : If the supply voltage is 220 volts 60 Hz, what is the operating voltage of the motor controller circuitry illustrated? EL-0011 A. 110 volts DC B. 110 volts AC C. 220 volts DC D. 220 volts AC

Last Answer : Answer: D

Description : As shown in the illustration, the D.C. motor's direction of rotation in changed by changing the _________________. EL-0101 A. polarity of the generator field B. direction of three-phase motor rotation C. direction of generator rotation D. polarity of the motor field

Last Answer : Answer: A

Description : Which component is responsible for energizing solenoid 'B1-B2' and releasing the brake for the winch motor shown in the illustration? EL-0102 A. Contactor '3M' B. A spring not shown in the schematic diagram C. Resistor 'B2-R1' D. Relay 'FR-B.O.'

Last Answer : Answer: A

Description : In the illustration if the compressor fails to start but the condenser fan motor is running the problem is _______. EL-0042 A. no power between L1 and L2 B. the yellow wire is open at the freezer temperature control switch C. the overload is open D. the blue wire from the defrost heater is open

Last Answer : Answer: C

Description : In the illustration if the compressor fails to start but the condenser fan motor is running the problem is _______. EL-0043 A. no power between L1 and L2 B. the yellow wire is open at the freezer temperature control switch C. the overload is open D. the blue wire from the defrost heater is open

Last Answer : Answer: C

Description : What operational characteristics do the components labeled as 'S' and 'R' represent in the motor controller diagram shown in the illustration? EL-0080 A. Standard and Reverse directions B. Stop and Restart features C. Subnormal and Regular loading D. Start and Run functions

Last Answer : Answer: D

Description : In the illustrated motor controller, the motor fails to start. A voltmeter reading between 1 and 6 reads line voltage, while the voltmeter reading between 2 and 6 reads 0 VAC. The problem is __________. EL- ... in the 'M' coil, 'Ma' contact/start switch or overload contacts D. fuse '10a' is blown

Last Answer : Answer: B

Description : Which of the listed conditions occur when '4th point lower' is selected on the winch shown in the illustration? EL-0102 A. Master switch contacts '3', '4', '6', '8', '9', & '10' close. B. Contactors '2, 3, & 4M' and ' ... , '7', '8', and '9' close. D. Contactors '1 & 3M' and '1, 2, & 3A' pick up.

Last Answer : Answer: B

Description : Which of the listed conditions occur when selection is made for 'third point hoist' on the winch shown in the illustration? EL-0102 A. Master switch contacts '5', '6', '7', '8', and '9' close. B. Contactors '2M', ' ... ' and '2A' drop out. D. Master switch contacts '3','4', '6', '8', and '9' close.

Last Answer : Answer: D

Description : The diagram shown in the illustration represents a _________. EL-0058 A. dual speed, 2-winding motor controller B. navigation running light circuit C. single phase, 2-motor selectable starter D. common fluorescent lighting circuit

Last Answer : Answer: B

Description : As shown in the illustration, which of the operations listed will happen when the 'jog button' is pushed? EL-0010 A. Coil 'CR' closes the normally open 'CR' contacts. B. Coil 'M' opens contact 'M'. C. Coil 'M' closes contact 'M'. D. Contact 'M' remains open despite the jog button being pushed.

Last Answer : Answer: C

Description : When 'selector switch' 'SEL8' shown in the illustration is in the 'TEST' position, contacts '3,4' and '7,8' are respectively ____________. EL-0100 A. open; closed B. closed; open C. open; open D. closed; closed

Last Answer : Answer: B

Description : When 'selector switch' 'SEL8' shown in the illustration is in the 'OFF' position, contacts '3,4' and '7,8' are respectively ____________. EL-0100 A. open; closed B. closed; open C. open; open D. closed; closed

Last Answer : Answer: A

Description : When 'selector switch' 'SEL8' shown in the illustration is in the 'ON' position, contacts '3,4' and '7,8' are respectively ______________. EL-0100 A. open; closed B. closed; open C. open; open D. closed; closed

Last Answer : Answer: D

Description : As shown in the illustration, 'H1' and 'H2' are ___________. EL-0058 A. fixed capacitors B. variable capacitors C. contacts, closed when the circuit is energized D. contacts, open when the circuit is energized

Last Answer : Answer: D

Description : During the start-up of the circuit shown in the illustration, it is noted that the ends of component 'C' remain lighted but the tube does not illuminate. The cause of this problem is ____________. EL- ... ' is closed C. component 'C' is the wrong wattage D. component 'B' contacts are stuck closed

Last Answer : Answer: D

Description : If the line voltage to the controller shown in the illustration is 440 volts, what voltage is applied across the motor when contacts 'S' close? EL-0080 A. 110 volts B. 220 volts C. 440 volts D. 660 volts

Last Answer : Answer: B

Description : The electrical schematic shown in the illustration indicates the lighting feeder circuit is _____________. EL-0014 A. three phase, 450 volt, and 60 cycle B. three phase, 120 volt, and 60 cycle C. single phase, 120 volt, and 60 cycle D. not specified

Last Answer : Answer: A

Description : In the schematic diagram of the DC compound generator shown in the illustration, the positive ammeter reading is 500 amps and the negative ammeter reading is 475 amps. What is the current flow through the neutral bus? EL-0037 A. 0 amp B. 12.5 amp C. 25 amp D. 975 amp

Last Answer : Answer: C

Description : If you reverse both the field and the armature connections to a DC propulsion motor, _____________. A. the direction of motor rotation will change B. the brushes will become overheated C. a magnetic lock will occur in the motor D. the direction of motor rotation will remain the same

Last Answer : Answer: D

Description : Which of the following actions must be carried out before a voltage tester can be used to test the three line fuses to a three-phase motor? A. The fuses must be removed from the circuit. B. The ... disconnected and tagged. D. Nothing need be done as long as the motor is running under a light load.

Last Answer : Answer: B

Description : The schematic diagram shown in the illustration represents which of the listed solid-state circuits? EL-0069 A. Bridge rectifier B. Magnetic amplifier C. Flip-flop generator D. Cathodic amplifier

Last Answer : Answer: A

Description : In an emergency, the fastest way to interrupt power and stop the winch shown in the illustration is for the ____________. EL-0102 A. mate to open the disconnect switch at 'L1' and 'L2' B. ... watch engineer to open the winch circuit breaker D. electrician to open the test link at the controller

Last Answer : Answer: B

Description : The winch shown in the illustration will not operate in any speed in the lowering direction and at an abnormal speed in 'first point hoist'. The possible cause is that _______________. EL-0102 A. ... '1M' in the power circuit are badly corroded D. master switch contacts 'MS6' have weak springs

Last Answer : Answer: B

Description : If the total source voltage of the three-wire distribution system shown in the illustration is 240 volts, what is the voltage across load L3? [NOTE: Kirchhoff's voltage and current laws apply.] EL-0075 A. 110.4 volts B. 112.2 volts C. 113.0 volts D. 114.8 volts

Last Answer : Answer: B

Description : In the lighting distribution circuit shown in the illustration, if all switches are closed and fuse 'F2' were to open, all lights on branches ____________. EL-0013 A. '1', '2', and '3' would go out B. '1' ... and '3' would burn dimly D. '1' and '3' would go out, while branch '2' would remain lit

Last Answer : Answer: D

Description : As shown in the illustration, which of the listed actions of the synchroscope pointer is occurring? EL-0002 A. Revolving slowly in the slow direction. B. Revolving rapidly in the slow direction. C. ... stationary at the 12 o'clock position since the leading edges of the A phases are in phase.

Last Answer : Answer: C

Description : To stop the electric motor shown in the illustration, the stop button is depressed, causing ____________. EL-0012 A. coil 'MS' to become de-energized B. contacts 'CR1' and 'MR4' to open C. contacts 'MR1', 'MR2', and 'MR3' to open D. contacts 'MS1', 'MS2', and 'MS3' to open

Last Answer : Answer: C

Description : Which of the illustrations listed below is representative of a motor controller's 'schematic' or 'elementary' diagram? A. EL-0023 B. EL-0007 C. EL-0037 D. EL-0058

Last Answer : Answer: B