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 circuit protection. Power supplies. Contactor relays. Motor drives. Circuit-breakers with thermal overload protection. Media converter. I/O rack. Communication. In the FIELD Motors. Solenoids on the hydraulic unit. Sensors. Other components Weather station. Obstruction lighting. 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 52070-00 235
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. Title block A good understanding of the title block (Figure 5-34) will help you navigate through the document. Current page General Title Zone (FIELD) Creator Version date Figure 5-34. Title block. Inside the electrical panel The electrical cabinet has fan to prevent heat from building up inside the cabinet. Electrical circuit protection If we refer to the electrical schematic we can see that the circuit breaker (Figure 5-35) and the main switch are located immediately after the network supply (Figure 5-36). Figure 5-35. Main circuit breaker. 236 Festo Didactic 52070-00
Ex. 5-1 Electrical Circuit and Panel Discussion Circuit breaker Main switch IEC tag Terminal number Line (L) Neutral (N) Ground (Protective earth PE) Figure 5-36. Circuit protection after the network supply. On the same page of the schematics, we see that fuses (Figure 5-37) protect the 24 V dc and 5 V dc power supplies: Figure 5-37. Fuse holder and fuse. Festo Didactic 52070-00 237
Ex. 5-1 Electrical Circuit and Panel Discussion 0.5 A fuse protecting the 5 V dc power supply 5 A fuse protecting the 24 V dc power supply Figure 5-38. Fuses protecting the power supplies. Power supplies The 24 V dc power supply (Figure 5-39) provides power to a variety of devices inside and outside the electrical panel, such as safety switches, sensors, relays, contactors, and the HMI. 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 a current up to 10 A. a The 24 V dc power supply is internally protected against short-circuits. Figure 5-39. 24 V dc power supply. The 5 V dc power supply (Figure 5-40) 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 a current up to 1.5 A. 238 Festo Didactic 52070-00
Ex. 5-1 Electrical Circuit and Panel Discussion Figure 5-40. 5 V dc power supply. Contactor relays Seven contactors such as the one depicted in Figure 5-41 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. Figure 5-41. Contactor. Table 5-1. Contactors usage. Contactor tag K1 K2 K3 K4 Controlled element Yaw motor Rotor (drivetrain) motor Hydraulic unit motor Generator K5, K6 Wind vane (one per direction) K7 Network supply (upon emergency stop) K8, K9 Supply safety K10 Emergency buttons Festo Didactic 52070-00 239
Ex. 5-1 Electrical Circuit and Panel Discussion Motor drives Three Siemens MICROMASTER variable-frequency drives like the one shown in Figure 5-42 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. You can restore these parameters from the SERVICE ROTOR AND GENERATOR screen by pressing DOWNLOAD DRIVE PARAM (password protected). Figure 5-42. AC drive. The circuit board of Figure 5-43 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 5-43. Anemometer (PWM) drive. Circuit-breakers with thermal overload protection Figure 5-44 is an example of a circuit-breaker that offers thermal circuit protection for the yaw, rotor, and hydraulic motor drives and motors if currents 240 Festo Didactic 52070-00
Ex. 5-1 Electrical Circuit and Panel Discussion 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. Figure 5-44. Circuit-breaker shown unlocked (left) and locked (right). Media converter An industrial Ethernet media converter allows communication between the PLC and an 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. I/O rack The I/O rack (Figure 5-45) of the nacelle includes a series of modules. Figure 5-45. I/O rack. Festo Didactic 52070-00 241
Ex. 5-1 Electrical Circuit and Panel Discussion 1. Interface module. Provides two PROFINET communication ports with RJ-45 connectors. 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, obstruction lighting, and system fault insertion. 9. Analog output voltage module. This module contains two ± 10 V dc voltage output ports (with selectable range) that control the PWM drive. Communication The electrical schematic provides information on how the PLC communicates with the various devices (Figure 5-46). 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. 242 Festo Didactic 52070-00
Ex. 5-1 Electrical Circuit and Panel Discussion By default, the HMI IP address is 10.100.100.12 and the PLC IP address is 10.100.100.11. Media converter PLC HMI AC drive Figure 5-46. Network arrangement. In the FIELD The field refers to what is inside the nacelle, protected by the safety panels. Items in the field are identified by the +FLD tag in the schematics. The electrical components in the field include motors, a generator, hydraulic unit solenoids, and sensors that are connected to the PLC I/O. Motors Yaw motor. Three-phase ac gear motor that drives the yaw axis via a pinion and slewing bearing assembly. Figure 5-47 shows how the motor is powered. Festo Didactic 52070-00 243
Ex. 5-1 Electrical Circuit and Panel Discussion The live wire circulates two times through the circuit-breaker with overload. The contactor switches the yaw motor on and off. Protective earth (ground) The motor drive provides 3-phase voltage to the motor. The motor is in the field (+FLD) Figure 5-47. Powering of the yaw motor. 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 can generate power. When not connected to the grid, 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 5-48). 244 Festo Didactic 52070-00
Ex. 5-1 Electrical Circuit and Panel Discussion Figure 5-48. Solenoid on a directional valve. Sensors 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. 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. Other components Weather station The anemometer circuit is wired as shown in Figure 5-49. A 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. Festo Didactic 52070-00 245
Ex. 5-1 Electrical Circuit and Panel Discussion Analog signal from PLC I/O PWM drive Anemometer Motor spinning the anemometer Pulse train signal going to the PLC I/O Figure 5-49. Anemometer. The wind vane position is simulated using a small 24 V dc gear motor which is controlled through contactors K5 and K6. 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. Obstruction lighting The two lights are controlled by two ports of a relay output card (R07-0 and R07-2). Figure 5-50. Obstruction lights. 246 Festo Didactic 52070-00
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. Festo Didactic 52070-00 247
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 safety reset 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 5-51below, using the electrical schematic. 248 Festo Didactic 52070-00
Ex. 5-1 Electrical Circuit and Panel Procedure 5 V dc power supply Breaker overload 24 V dc power supply Relay output AC drive Media converter PWM drive Contactor Fuse holder Main breaker PLC CPU 24 V dc power supply Safety relay Figure 5-51. Electrical panel. Main breaker 6. Locate the main breaker. What is the rated current and type (B, C, D, K or Z)? Festo Didactic 52070-00 249
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 5-52), what resistance value do you obtain for the fuse? Figure 5-52. 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. 250 Festo Didactic 52070-00
Ex. 5-1 Electrical Circuit and Panel Procedure 13. Using the multimeter, do you measure continuity between this terminal and the grounding screw attached to the casing of the electrical panel (Figure 5-53)? Yes No Figure 5-53. Electrical panel ground terminals. 14. Do you measure continuity between the power supply PE terminal and the metallic armor of the thermocouple cables? Yes No Emergency stop 15. Position the two probes of your multimeter on terminals 1 and 2 of the emergency stop, as shown in Figure 5-54. Figure 5-54. Continuity of emergency stop. 16. What do you observe when the switch is in its normal position and when it is depressed? Festo Didactic 52070-00 251
Ex. 5-1 Electrical Circuit and Panel Procedure 17. According to the schematics, to which contactor terminal are the two emergency stops connected to? Contactors 18. Go to the page showing the yaw motor in the schematics. 19. What is the type of component with the IEC tag F1? b You can click on the tag to go to the part specification page. 20. What is the type of component with the IEC tag K2? 21. Through which terminals of this component does the neutral ( N ) line pass? 22. 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. 23. Check the continuity of each of the four pairs of contacts when you push and release the test button (Figure 5-55). What type of contacts are they? Figure 5-55. Testing continuity on the component. 252 Festo Didactic 52070-00
Ex. 5-1 Electrical Circuit and Panel Procedure Energizing the system 24. Ask everyone to remove their individual padlock and tag. Next, remove the hasp from the main switch. 25. 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. 26. Turn on the main power switch. Wait for the HMI to boot and log into Windows. The HMI should start automatically. 27. Press the safety reset button. 28. Press Start Trainer in the HMI MAIN screen. 29. 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. 30. Put the trainer in MANUAL mode. Drive parameters Reading current parameters 31. 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. 32. 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 Festo Didactic 52070-00 253
Ex. 5-1 Electrical Circuit and Panel Procedure 33. 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. 34. Repeat steps 32 and 33 for the rotor and hydraulic unit drives. 35. On the MANUAL screen (Press the MANUAL OPERATION button to access the screen), release the yaw and rotor brakes. 36. 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)? 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 37. 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)? 38. According to your results so far, what seems to be the relationship between the motor speed and the drive output frequency? 254 Festo Didactic 52070-00
Ex. 5-1 Electrical Circuit and Panel Procedure 39. 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)? 40. 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. 41. Go to the SERVICE HYDRAULIC screen and activate the DEBUG mode. 42. Open the front safety panel. 43. Temporarily actuate the pressure relief valve (MV1) to activate the hydraulic pump. Use the drive FN button to monitor the hydraulic unit motor drive. Record all the displayed values in Table 5-3. 44. 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. 45. Close the front safety panel. 46. Stop the DEBUG mode. Turn off drive contactor 47. Turn off the hydraulic unit drive contactor breaker overload. Festo Didactic 52070-00 255
Ex. 5-1 Electrical Circuit and Panel Procedure 48. Which alarms are generated? 49. On the MAIN screen, you can see the following information: Figure 5-56. Missing interlock. Which screen provides you with the state of each interlock condition? Which interlock condition is not met? 50. Turn on the hydraulic unit drive breaker overload. 51. Reset and acknowledge all of the alarms. Modify a drive parameter 52. 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. 53. Press the up arrow button until P1082 (Max. frequency) is displayed. 54. Press P again to be able to change the value. 55. Press the down arrow button until you obtain 10.00 Hz. 56. Press P once more to confirm and store the value. 57. 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 256 Festo Didactic 52070-00
Ex. 5-1 Electrical Circuit and Panel Procedure 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. 58. 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 5-57). Figure 5-57. SERVICE DRIVE PARAMETERS. Festo Didactic 52070-00 257
Ex. 5-1 Electrical Circuit and Panel Conclusion 59. Press DOWNLOAD PARAM. in the Yaw Drive zone. During download (Figure 5-58), the drive should display the following characters: P - - - -. Figure 5-58. Download in progress. 60. 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 61. Use the main power switch to turn all system power off. 62. 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 is the IEC tag of the contactor for the hydraulic unit? 2. What is the 5 V dc power supply used for? 3. What is the rack and slot number of the PLC card to which the thermocouples are connected and what is the card part number? 258 Festo Didactic 52070-00