Exercise 5-1 Electrical Circuit and Panel EXERCISE OBJECTIVE When you have completed this exercise, you will be familiar with the trainer electrical schematic and components. DISCUSSION OUTLINE The Discussion of this exercise covers the following points: Detailed electrical schematic Title block. Inside the electrical panel (ELECTRICAL CABINET) Electrical circuit protection. Power supplies. Contactor relays. Motor drives. Circuit-breakers with thermal overload protection. Media converter. Distributed I/O rack. Communication network. In the FIELD Motors. Solenoids on the hydraulic unit. Sensors. The POWER GENERATION PANEL Weather station. FAA obstruction lighting. Optional power generation assembly. DISCUSSION Detailed electrical schematic The complete, IEC-style, electrical schematic is provided as a separate document or PDF file (Figure 5-33). Figure 5-33. First page of the IEC-style electrical schematic. Festo Didactic 88765-00 237
Ex. 5-1 Electrical Circuit and Panel Discussion This electrical schematic runs over several pages, but a large proportion of the document consists of component specifications at the end. If you have not had the chance yet, now might be a good time to go through the different sections on your own. The schematics will be used during the procedure. a If you have access to the PDF file, you can click on tags to go from one instance of a reference to another. The schematics are divided into three zones: ELECTRICAL CABINET (+EC) FIELD (+F) POWER GENERATION PANEL (+PGP) Our analysis of the electrical circuit will reflect the same structure. Title block A good understanding of the title block (Figure 5-34 and Figure 5-35) will help you navigate through the document. Previous page number Version date General Title Figure 5-34. Title block (left). Next page Page title Model number Zone (FIELD) Current page Figure 5-35. Title block (right). Total number of pages Inside the electrical panel (ELECTRICAL CABINET) Most of your trainer electrical components are located inside the electrical panel. The electrical panel layout (Figure 5-36) is posted inside the cabinet (to the left side) for easy identification of each component. The nacelle trainer electrical box has louvers at the top and bottom for ventilation. This feature permits air to enter at the bottom and exit at the top of the enclosure in a natural fashion, which prevents heat from building up inside the cabinet. 238 Festo Didactic 88765-00
Ex. 5-1 Electrical Circuit and Panel Discussion Figure 5-36. Electrical panel layout. Electrical circuit protection If we refer to page 3 of the electrical schematic, titled Power, we can see that the circuit breaker (Figure 5-37) and the main switch are located immediately after the network supply (Figure 5-38). Festo Didactic 88765-00 239
Ex. 5-1 Electrical Circuit and Panel Discussion Figure 5-37. Main circuit breaker. Main switch Terminal number Circuit breaker IEC tag Our tag Our part number Ground (Protective earth PE) Line (L) Neutral (N) Figure 5-38. Circuit protection after the network supply. 240 Festo Didactic 88765-00
Ex. 5-1 Electrical Circuit and Panel Discussion On the same page, we see that fuses (Figure 5-39) protect the 24 V dc and 5 V dc power supplies: Figure 5-39. Fuse holder and fuse. 0.5 A fuse protecting the 5 V dc power supply 5 A fuse protecting the 24 V dc power supply Figure 5-40. Fuses protecting the power supplies. Festo Didactic 88765-00 241
Ex. 5-1 Electrical Circuit and Panel Discussion Power supplies The 24 V dc power supply (Figure 5-41) provides power to a variety of devices inside and outside the electrical panel, such as safety switches, sensors, relays, contactors, and the Panel PC. The power supply is compatible with input voltages between 85 V to 262 V at frequencies between 47 Hz and 63 Hz and can provide up to 10 A. a The 24 V dc power supply is internally protected against short-circuits. Figure 5-41. 24 V dc power supply. The 5 V dc power supply (Figure 5-42) is there only to feed the wind vane. It is compatible with input voltages between 90 V to 264 V at frequencies between 47 Hz and 63 Hz and can provide up to 1.5 A. c See page 24 of the electrical schematic. Figure 5-42. 5 V dc power supply. Contactor relays Seven contactors such as the one depicted in Figure 5-43 are mounted on a DIN rail inside the cabinet. They switch the elements listed in Table 5-1 on and off when 24 V dc is applied or removed from the contactor coils. They each have NO contacts and power contacts that can carry a maximum of 7 A of inductive current (i.e., when controlling motors), or 18 A of resistive current. 242 Festo Didactic 88765-00
Ex. 5-1 Electrical Circuit and Panel Discussion Figure 5-43. Contactor. Table 5-1. Contactors usage. Contactor tag Controlled element Reference page K1 Network supply (upon emergency stop) 3.8 K3 Yaw motor 16.1 K4 Rotor (drivetrain) motor 17.1 K5 Hydraulic unit motor 18.1 K10 Generator 21.1 K11, K12 Wind vane (one per direction) 24.3 Motor drives Three Siemens MICROMASTER variable-frequency drives like the one shown in Figure 5-44 provide precision control to the yaw, rotor, and hydraulic pump motors. Their display and buttons give you access to the following information: DC Link. The voltage of the internal bus, in volts. Output current. The actual current supplied to the motor, in amperes. Output voltage. The voltage supplied to the motor by the drive, in volts. Output frequency. The frequency of the current supplied by the drive, in hertz. You can change some parameters such as the current limit (P0640), frequency range (P1080 and P1082), ramp-up time (P1120), or ramp-down time (P1121). However, during normal operation, drives should always be left with the default settings from our company. You can restore these parameters from the SERVICE ROTOR AND GENERATOR screen by pressing DOWNLOAD DRIVE PARAM (password protected). Festo Didactic 88765-00 243
Ex. 5-1 Electrical Circuit and Panel Discussion Figure 5-44. AC drive. The circuit board of Figure 5-45 is a PWM drive that controls the motor that spins the anemometer in order to simulate various wind speeds. This component is used for wind simulation and is not found in a typical nacelle. Figure 5-45. Anemometer (PWM) drive. Circuit-breakers with thermal overload protection Figure 5-46 is an example of a circuit-breaker that offers thermal circuit protection for the yaw, rotor, and hydraulic motor drives and motors if currents are too high for a long period of time. Additionally, each of these circuit-breakers can be locked individually when turned off by pulling the perforated tab on the rotary switch. 244 Festo Didactic 88765-00
Ex. 5-1 Electrical Circuit and Panel Discussion Figure 5-46. Circuit-breaker shown unlocked (left) and locked (right). Media converter An industrial Ethernet media converter allows communication between the PLC and the optional external hub training system. This interface bidirectionally converts between electrical Ethernet signals and optical fiber signals. It provides one 10/100Mbit/s RJ-45 port and one 100 Mbit/s BOFC port for a PROFINET system. Distributed I/O rack The distributed I/O rack (Figure 5-47) of the nacelle includes a series of modules. Festo Didactic 88765-00 245
Ex. 5-1 Electrical Circuit and Panel Discussion Figure 5-47. Distributed I/O rack. 1. Interface module. Provides two PROFINET communication ports with RJ-45 connectors and contains an integrated switch to transfer data between the PLC and the distributed I/O ports. It also supports an external micro memory card which contains the configuration parameters. 2. Power module. Monitors supply voltage of the other PLC cards. If the PWR LED is off, there is no load voltage. If the red SF LED is on, there is a problem with a module. 3. Digital input modules. Each of these three modules has eight digital inputs for a total of 24 ports that accept high (24 V dc) or low (0 V dc) voltage signals from various safety switches and sensors throughout the training system. Two ports are used to count low-frequency digital pulses from the anemometer (wind speed) sensor and from the low-speed shaft sensor. 4. Encoder/counter modules. These two modules have two 24 V dc digital inputs each and can measure frequencies up to 100 khz. They count high frequency digital pulses coming from the yaw encoder and from the high-speed shaft sensor switch. 5. Analog input module (voltage). This module contains two ± 10 V dc voltage input ports (with selectable range); one for the wind vane feedback, the other for the rotor brake pressure transducer (PSB2). 6. Analog input module (thermocouple). This module contains two 80 mv thermocouple input ports. These inputs are used to measure the gearbox and generator temperature via two J-type thermocouple junctions. 7. Analog input module (current). The last analog input module has two 4-20 ma current input ports. One monitors the vibration sensor and the other monitors the accumulator pressure transducer (PSP2). 8. Digital output relay modules. Twelve modules with two digital outputs each for a total of 24 ports that control motor contactors, solenoid valves on the hydraulic unit, FAA obstruction lighting, and system fault insertion. 246 Festo Didactic 88765-00
Ex. 5-1 Electrical Circuit and Panel Discussion 9. Analog output voltage module. This module contains two ± 10 V dc voltage output ports (with selectable range) that control the PWM drive. Communication network The electrical schematic provides information on how the communication network is built (Figure 5-48). Three communication standards are involved: PROFIBUS, PROFINET, and Ethernet. PROFIBUS is a widely used field bus standard that is used for data communication in industrial applications. It is commonly used to provide single cable interfacing during the automation of production lines in manufacturing plants. PROFINET is an industrial Ethernet networking standard that is often used for real-time automation of manufacturing processes. By default, the Panel PC IP address is 10.100.100.11 and its PROFINET address is 192.168.1.11. The distributed I/O system PROFINET address is 192.168.1.20. Distributed I/O Media converter Panel PC AC drive Figure 5-48. Network arrangement. In the FIELD The field refers to what is inside the nacelle, protected by the safety panels. The electrical components in the field include motors, a generator, hydraulic unit solenoids, and sensors that are connected to the distributed I/O. Motors c See pages 16, 17, 18, and 21 of the electrical schematic. Yaw motor. Three-phase ac gear motor that drives the yaw axis via a pinion and slewing bearing assembly. Figure 5-49 shows how the motor is powered. Festo Didactic 88765-00 247
Ex. 5-1 Electrical Circuit and Panel Discussion Components inside the dotted line are in the electrical cabinet (EC). The live wire circulates three times through the circuit-breaker with overload. The contactor switches the yaw motor on and off. Protective earth (ground) This rectifying circuit provides higher voltage (120 V models only). The motor drive provides 3-phase voltage to the motor. The motor is outside the dotted line, in the field (+F in the reference box) Figure 5-49. Powering of the yaw motor. 248 Festo Didactic 88765-00
Ex. 5-1 Electrical Circuit and Panel Discussion Rotor (drive train) motor. Three-phase ac motor that drives the rotor (low-speed shaft) via a chain drive. This motor is present for simulation purposes. Hydraulic unit motor. Three-phase ac motor that drives the hydraulic unit pump to provide fluid pressure. Generator. Three-phase induction motor that sends power to the grid, if the optional power generation panel is present. Otherwise, the generator can be considered a mechanical load. Solenoids on the hydraulic unit Directional valves SV1 through SV6 can be operated manually or via a solenoid (Figure 5-50). c See page 19 of the electrical schematic. Figure 5-50. Solenoid on a directional valve. Sensors c See pages 18, 19 and 20 of the electrical schematic. The yaw position transducer is found on page 16. Pressure sensors. Two pressure transducers (PSP2 and PSB2) and a pressure switch (PSB1) give feedback about the hydraulic system condition. Low- and high-speed sensors. Inductive sensors that turn on and off as the low- and high-speed shafts rotate. Rotor lock sensor. Inductive sensor that detects if the manually operated rotor lock is in place. Thermocouples. Two bimetallic temperature sensors provide a voltage based on the absolute temperature measured at the generator and at the gearbox. Cable twist detector. Limit switch that senses when too much physical strain is placed on the wires and/or cables inside the yaw section of the nacelle trainer. Festo Didactic 88765-00 249
Ex. 5-1 Electrical Circuit and Panel Discussion a Vibration sensor. Motion detector that can be placed at one of many remote locations in the training system. Yaw position transducer. Optical encoder wheel used to determine the position and direction of the yaw axis. Safety panel switches are considered part of the ELECTRICAL CABINET zone. The POWER GENERATION PANEL The power generation panel comprises the weather station, FAA obstruction lighting, and the optional power generation assembly. Weather station c See pages 23 and 24 of the electrical schematic. The anemometer circuit is wired as shown in Figure 5-51. A distributed I/O analog output sends a 0-5 V dc voltage signal to the PWM drive, which makes the motor spin the anemometer according to the wind speed set in the simulation screen. The anemometer sends a pulse train signal whose frequency is proportional to the rotation speed back to the control circuit. Analog signal from distributed I/O PWM drive Anemometer Motor spinning the anemometer Figure 5-51. Anemometer. Pulse train signal going to the distributed I/O The wind vane (page 24) position is simulated using a small 24 V dc gear motor which is controlled through contactors K11 and K12. The feedback is a 0.25 V dc to 4.75 V dc signal proportional to the wind vane current angular position. This means that the simulation and actual measurement are independent. 250 Festo Didactic 88765-00
Ex. 5-1 Electrical Circuit and Panel Discussion FAA obstruction lighting c See page 23 of the electrical schematic. The two lights are controlled by two ports of a relay output card (R07-0 and R07-2). Figure 5-52. FAA obstruction lights. Optional power generation assembly Page 22 of the electrical schematic shows how the power generation panel of Figure 5-53 is built. More information on the subject is available in a separate manual. Figure 5-53. Nacelle with and without the power generation option. Festo Didactic 88765-00 251
Ex. 5-1 Electrical Circuit and Panel Procedure Outline PROCEDURE OUTLINE The Procedure is divided into the following sections: Accessories needed Basic safety procedure Preparation question Lockout/tagout procedure Component identification Main breaker Checking the continuity of a fuse Protective earth (ground) Emergency stop Contactors Energizing the system Drive parameters Reading current parameters. Turn off drive contactor. Modify a drive parameter. Restore parameters. End of the procedure PROCEDURE Accessories needed For this exercise, you will need the following accessories: Lockout device (hasp) One padlock and one tag per student Multimeter (not included) Basic safety procedure Before using the training system, complete the following checklist: You are wearing safety glasses and safety shoes. You are not wearing anything that might get caught such as a tie, jewelry, or loose clothes. If your hair is long, tie it out of the way. The working area is clean and free of oil or water. Preparation question 1. What are the hp ratings of the yaw and rotor motors? b Refer to the electrical schematic. 252 Festo Didactic 88765-00
Ex. 5-1 Electrical Circuit and Panel Procedure Lockout/tagout procedure 2. Make sure the main switch is off and everything is secure inside and around the nacelle. 3. Install the lockout hasp in the main switch. Next, install the student padlocks and tags in the hasp. 4. Try to turn on the main switch to verify that the system is electrically isolated. Press the start push-button to test whether the system can be energized. Component identification 5. Get closer to the electrical panel and take a look at it. Identify parts in Figure 5-54 below, using the electrical panel layout and electrical schematic. Festo Didactic 88765-00 253
Ex. 5-1 Electrical Circuit and Panel Procedure 5 V dc power supply Breaker overload 24 V dc power supply Distributed I/O power module Relay output AC drive Media converter PWM drive Contactor Fuse holder Main breaker Interface module Figure 5-54. Electrical panel. Main breaker 6. Locate the main breaker. What is the rated current and type (B, C, D, K or Z)? 254 Festo Didactic 88765-00
Ex. 5-1 Electrical Circuit and Panel Procedure 7. What is the position of the breaker lever when the switch is open ( O )? Checking the continuity of a fuse 8. Which fuse holder (left or right) protects the 5 V dc power supply? And what is the current rating of the fuse? 9. Remove the fuse from this holder. Using a multimeter (Figure 5-55), what resistance value do you obtain for the fuse? Figure 5-55. Measuring the continuity of a fuse. 10. Using your multimeter, determine which terminal of the fuse holder (top or bottom) is connected to the L terminal of the 5 V power supply. 11. Put the fuse back in the holder. Take good care to put the right fuse in the right holder. Failure to do so may result in damage to the equipment or a series of blown fuses. Protective earth (ground) 12. Locate the PE terminal of the 24 V dc power supply. Festo Didactic 88765-00 255
Ex. 5-1 Electrical Circuit and Panel Procedure 13. Using the multimeter, do you measure continuity between this terminal and the ground terminals at the bottom-left corner of the panel (Figure 5-56)? Yes No Figure 5-56. Electrical panel ground terminals. 14. Do you measure continuity between the power supply PE terminal and screws attached to the casing of the electrical panel? Yes No 15. Do you measure continuity between the power supply PE terminal and the metallic armor of the thermocouple cables? Yes No Emergency stop 16. Position the two probes of your multimeter to terminals 1 and 2 of the emergency stop (second side), as shown in Figure 5-57. Figure 5-57. Continuity of emergency stop. 256 Festo Didactic 88765-00
Ex. 5-1 Electrical Circuit and Panel Procedure 17. What do you observe when the switch is in its normal position and when it is depressed? 18. According to the IEC schematics (page 14, Emergency Stop & Guard Protection ), to which contactor terminal are the two emergency stops connected to? a Assume the FAULT 2 box on page 14 is a short circuit. 19. Verify your affirmation by checking continuity between the emergency stop and the terminal with a multimeter. The good terminal will show the lowest resistance. 20. On which page of the electrical schematics can you find terminals 1, 2, 3, and 4 of this contactor? b All terminals from a single contactor are conveniently shown together at the bottom of the schematics to help localize them on the schematics. Contactors 21. Go to the page concerning the yaw motor (page 16, YAW Motor ) of the IEC schematics. 22. What is the type of component with the IEC tag Q1? b You can click on the tag to go to the part specification page. 23. What is the type of component with the IEC tag K3? 24. Through which terminals of this component does the neutral ( N ) line pass to get to the rectifier? Festo Didactic 88765-00 257
Ex. 5-1 Electrical Circuit and Panel Procedure 25. Which terminals of this component provide feedback about the motor state to the PLC? b All terminals from a single contactor are conveniently shown together at the bottom of the schematics to help localize them on the schematics. 26. Check the continuity of each of the four pairs of contacts when you push and release the test button (Figure 5-58). What type of contacts are they? Figure 5-58. Testing continuity on the component. Energizing the system 27. Ask everyone to remove their individual padlock and tag. Next, remove the hasp from the main switch. 28. Notify all the people working around the nacelle that the system is about to be energized and ask your instructor for permission to power the nacelle training system. 29. Turn on the main power switch. Wait for the panel PC to boot and log into Windows. The HMI should start automatically. 30. Press the green (physical) start button under the main switch to start the system. 31. Press Start Trainer in the HMI MAIN screen. 32. If the ALARMS button is flashing red at this point, press it. In the opening ALARMS screen, acknowledge each current alarm. Next, press RESET ALARMS, if necessary. 258 Festo Didactic 88765-00
Ex. 5-1 Electrical Circuit and Panel Procedure 33. Put the trainer in MANUAL mode. Drive parameters Reading current parameters 34. Check the displays on the three motor drives to ensure that power is applied to each motor drive. You should see a lit display with a numeric value. 35. On the leftmost (yaw) motor drive, press and hold down the FN (function) button for at least two seconds. The (input) DC link voltage (in V dc) should appear, preceded by the character d. Write this value in Table 5-2. Table 5-2. Motor drives information at rest. Motor drive DC Link (V dc) Output current (A ac) Output voltage (V ac) Output frequency (Hz) Yaw Rotor Hydraulic unit 36. Press the FN button again to see successively: the AC output current (in A ac) the AC output voltage (in V ac) preceded by the character o the output frequency (in Hz). Record all the displayed values in Table 5-2. 37. Repeat steps 35 and 36 for the rotor and hydraulic unit drives. 38. On the MANUAL screen (Press the MANUAL OPERATION button to access the screen), release the yaw and rotor brakes. 39. Rotate the yaw using the JOG+/- buttons. During that time, press the drive FN button to display the four values again and record these values in Table 5-3. What is the maximum speed obtained (in RPM)? Festo Didactic 88765-00 259
Ex. 5-1 Electrical Circuit and Panel Procedure Table 5-3. Motor drives information during operation. Motor drive DC Link (V dc) Output current (A ac) Output voltage (V ac) Output frequency (Hz) Yaw (jog) Yaw (move) Rotor Hydraulic unit 40. Rotate the yaw again by entering a value in the Target Manual field and using the MOVE TO POSITION button. During that time, press the drive FN button to display the four values again and record these values in Table 5-3. What is the maximum speed obtained (in RPM)? 41. According to your results so far, what seems to be the relationship between the motor speed and the drive output frequency? 42. Press and hold the JOG button to run the rotor motor while using the drive FN button to display the four values again. Record all the displayed values in Table 5-3. What is the maximum speed obtained (in RPM)? 43. Which motor draws more current when using the JOG button, the yaw or the rotor motor? Is it the motor with the highest or lowest hp rating? b Refer to the preparation question. 44. Go to the SERVICE HYDRAULIC screen and activate the DEBUG mode. 45. Open the front safety panel. 46. Temporarily actuate the pressure relief valve (MV1) to activate the hydraulic pump. Use the drive FN button to monitor the hydraulic unit motor drive. 260 Festo Didactic 88765-00
Ex. 5-1 Electrical Circuit and Panel Procedure Record all the displayed values in Table 5-3. 47. Deactuate the pressure relief valve (MV1) and observe what happens to the drive output current parameter until the pressure relief valve can be heard. Explain what happens in terms of the oil pressure that is building inside the system. 48. Close the front safety panel. 49. Stop the DEBUG mode. Turn off drive contactor 50. Turn off the hydraulic unit drive contactor breaker overload. 51. Which alarms are generated? 52. On the MAIN screen, you can see the following information: Figure 5-59. Missing interlock. Which screen provides you with the state of each interlock condition? Which interlock condition is not met? 53. Turn on the hydraulic unit drive breaker overload. Festo Didactic 88765-00 261
Ex. 5-1 Electrical Circuit and Panel Procedure 54. Reset and acknowledge all of the alarms. Modify a drive parameter 55. Press the P button once on the yaw drive to have access to the parameters. a If you cannot access the parameters, it might be because you are trapped into the function menu. Press the FN button for about two seconds to escape. 56. Press the up arrow button until P1082 (Max. frequency) is displayed. 57. Press P again to be able to change the value. 58. Press the down arrow button until you obtain 10.00 Hz. 59. Press P once more to confirm and store the value. 60. Go to the MANUAL OPERATION screen and rotate the yaw again by entering a value in the Target Manual field and using the MOVE TO POSITION button. During that time, press the drive FN button to display the output frequency. What do you observe in terms of output frequency and maximum yaw speed now? Explain. a Release the yaw brake if necessary. Restore parameters a You can restore any parameter individually using the method used previously. However, if you do not remember the original value or if more than one parameter needs to be restored, it might be a good idea to push all the original values to the drive at once using the method described below. 262 Festo Didactic 88765-00
Ex. 5-1 Electrical Circuit and Panel Procedure 61. Go to the SERVICE ROTOR AND GENERATOR screen and press DOWNLOAD DRIVE PARAM. Ask your instructor to enter the appropriate user name and password so you can access the SERVICE DRIVE PARAMETERS screen (Figure 5-60). Figure 5-60. SERVICE DRIVE PARAMETERS. 62. Press DOWNLOAD PARAM. in the Yaw Drive zone. During download (Figure 5-61), the drive should display the following characters: P - - - -. Figure 5-61. Download in progress. Festo Didactic 88765-00 263
Ex. 5-1 Electrical Circuit and Panel Conclusion 63. Go back to the MANUAL OPERATION screen and rotate the yaw again. Are the output frequency and maximum yaw speed back to their original values? a Yes No Release the yaw brake if necessary. End of the procedure 64. Exit the HMI by pressing X on the top-right corner of the screen. 65. Press the Windows Start button, select Shut Down, and press OK. Wait for the system to turn off. a You may have to reset alarms before exiting the software. 66. Use the main power switch to turn all system power off. 67. Clean the area. CONCLUSION In this exercise, you became familiar with the electrical panel components and schematics. You identified the components and tested their operation while the system was de-energized. Then, you observed, modified, and restored drive parameters and examined what happened when contactor power is lost. REVIEW QUESTIONS 1. What are the three zones used in the nacelle electrical schematic? 2. What is the IEC tag of the contactor for the hydraulic unit? 3. What is the 5 V dc power supply used for? 264 Festo Didactic 88765-00
Ex. 5-1 Electrical Circuit and Panel Review Questions 4. What is the rack and slot number of the PLC card to which the thermocouples are connected and what is the card part number? 5. How many switches can be triggered by the opening of a safety panel? Where do they take their power from? Festo Didactic 88765-00 265