Bus Regulation PowerFlex 755 AC Drives For Classroom Use Only!
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Intro Steps Contents Contents... 3 Before you begin... 4 About this lab... 4 Tools & Prerequisites... 4 Network Setup... 5 About the PowerFlex 755 DHQ Demo Box... 6 Drive Setup Reset Defaults... 7 Drive Setup Auto Tune and Configuration Parameters... 8 Connect to the Drive using Connected Components Workbench... 8 Configuring Drive Parameters... 9 Demonstrating an Unregulated Bus... 12 Adjust Frequency... 13 Dynamic Braking... 14 3 of 16
Before you begin Please review the following information before starting this lab. About this lab This session provides you with an opportunity to explore Bus Regulation features supported by the PowerFlex 755 drive. In this lab, you will: Demonstrate a scenario in which Bus Regulation is disabled Explore Adjust Frequency Explore Dynamic Braking This lab takes approximately 30 minutes to complete. Lab Objective At the end of this lab you will be able to: 1. Configure the drive to Regulate the Bus using the Adjust Frequency feature 2. Configure the drive to Regulate the Bus using Dynamic Braking Tools & Prerequisites Software programs required Connected Components Workbench v9.01 RSLinx Classic v3.80.00 Hardware devices required PowerFlex 755 DHQ Demo Box (PN-39023) o PowerFlex 755 AC Drive (20G11-N-B-DM1AA6K32V8) v12.001 Ethernet patch cables Motor with Flywheel Braking Resistor Demo 4 of 16
Network Setup Ethernet Connections 1 PC PF755 Ethernet Port Set IP Address of PowerFlex 755 to 192.168.1.30 by setting the IP address switches. Hundreds 0 Tens 3 Ones 0 Motor with Flywheel attached Braking Resistor 5 of 16
About the PowerFlex 755 DHQ Demo Box 6 of 16
Drive Setup Reset Defaults Use the steps below to reset the drive to its default settings. 1. Press the Folders button on the HIM keypad. The button is located on the bottom row of the HIM Keypad (shown circled in the left image below). Pressing the Folders button changes the HIM screen display to the Folders screen (see right image below). 00 PowerFlex 755 240V 4.2A 20G... B4P2 PORTS 00 PowerFlex 755 01 20-HIM-x6 05 Universal Fdbk 06 Dual Encoder 2. Use the Enter key located in the center of the HIM keypad to select 00 PowerFlex 755. 3. Now, use the left or right arrow keys to navigate to the Memory heading, then select Set Defaults. 4. Select This port only, then select the All option using the Enter key. At this time the drive may display Fault 58, which is expected. 5. Clear the fault using the Red stop key (if necessary), then Confirm the reset. 6. Press ESC twice to return to the main display. 7 of 16
Drive Setup Auto Tune and Configuration Parameters Use the settings below to auto tune the drive, and configure certain parameters for the lab. Connect to the Drive using Connected Components Workbench 1. Open Connected Components Workbench using the icon on the desktop. 2. In the Device Toolbox expand Discover, then click Browse Connections in the Device Toolbox to open the Connection Browser. 3. Browse to AB_ETH-1, Ethernet, and select 192.168.1.30, PowerFlex 755. CCW will now connect to the drive, showing its information in the main pane of the software window. 8 of 16
Configuring Drive Parameters 1. Select the Parameters button to view the parameters for the PowerFlex 755 drive. 2. Using the Group drop down list, expand Motor Control and select Motor Data. 3. Fill in the following parameters with the values found on the motor nameplate at this station. Motor NP Volts Motor NP Amps Motor NP Hertz Motor NP RPM Motor NP Power Be sure to press Enter after filling in each value to be sure the entry is confirmed. 4. Next, select Mtr Ctrl Options from the Group drop down list, and change the following parameter, being sure to press Enter after the change: Motor Control Mode Induction FV 9 of 16
5. In the Group drop down menu, expand Drive Cfg and select Preferences. Change the following parameters: 300 Speed Units RPM 301 Access Level - Expert 6. In the Group drop down menu, expand Speed Control, select Speed Reference and change the following parameters: 545 Speed Ref A Select Port 0: Preset Speed 1 (Picture A) 571 Preset Speed 1 1400 (Picture B) Picture A Picture B 7. In the Group drop down menu, select Speed Regulator, and change the following parameter: 636 - Speed Reg BW 5 8. In the Group drop down menu, expand Drive Cfg, then select Braking Features, and change the following parameter: 409 - Dec Inhibit Act Ignore 10 of 16
Auto Tune Follow the steps below to Auto Tune the Drive. 1. Using the Group drop down list, expand Motor Control and select Autotune, then change the Autotune value to Rotate Tune. Be sure to press Enter to confirm the Autotune value change. 2. Turn to the drive, and press the green Start button. The drive will start its auto tune process. Follow its process using the display on the drive HIM module. Inertia Tune The motor has a large disk attached to the end of its shaft. By default, the Inertia parameter has a value of 2.00. In order to make sure that the drive s information is as precise as possible, run an Inertia tune on the drive using CCW to update that value to match the actual Inertia acting on the motor. 1. In CCW, in the Autotune field, select Inertia Tune. 2. Turn to the drive, and press the green Start button. Follow the process on the HIM module of the drive. The drive has now completed its auto tune procedure. And has updated the remaining parameters determined during the process. You can now continue to the next section. 11 of 16
Bus Regulation Bus Regulation can be useful in a variety of scenarios where the motor shaft may be turning faster than the synchronous speed set by the drive. In these cases, the motor is regenerating power, and must be handled in order to protect other components in the system. Use the example below to demonstrate what happens when bus regulation is disabled. Then explore two of the options available for Bus Regulation. Demonstrating an Unregulated Bus 1. In the Group drop down list, select Mtr Ctrl Options found under Motor Control. Change the 35 Motor Ctrl Mode value to Induction SV. 2. In CCW, click the Groups drop down list, expand Speed Control, and select Slip/Droop Comp. Change the following parameter: 621 Slip RPM at FLA 0 3. In the Groups drop down list, select Speed Ramp Rates, and change the following parameter: 537 Decel Time 1 5 Be sure to press Enter to confirm the value change. 4. Expand Drive Cfg and select Start Features, and change the following parameter: 356 Flying Start Mode Enhanced 12 of 16
5. Next, use the Groups drop down list, expand Drive Cfg and select Braking Features. Change or verify the following parameters: 370 Stop Mode A Ramp 372 Bus Reg Mode A Disabled 6. Turn to the drive, and press the Start button. Allow the motor to come up to speed. 7. Use the Stop button to stop the drive. Notice that the drive will immediately fault. The energy from the motor has increased the bus voltage to a point at which the drive trips. This function protects the internal components of the drive. 8. Clear the fault using the HIM module. Adjust Frequency 1. In CCW, change parameter 372 Bus Reg Mode A to Adjust Freq. 2. Start the motor using the Start button. Allow the motor to come up to speed. 3. Use the Stop button to stop the drive, and count off 5 seconds. Notice that the motor is not stopping within the 5 second ramp time that was configured earlier. This is due to bus regulation the drive is sacrificing speed control in order to keep the bus voltage at a regulated level. 13 of 16
Dynamic Braking 1. In CCW, change the 372 Bus Reg Mode A value to Dyn Brake. 2. Next, change the following parameters using the Dynamic Brake Resister Nameplate: The values on the Name Plate should match those in the list below if this is not the case, use the values on the Resistor Nameplate instead. 382 DB Resistor Type External 383 DB Ext Ohms 110 384 DB Ext Watts 800 385 DB ExtPulseWatts 16000 (if unable to find this number multiply the Watts [parameter 384] value by 20) 3. Start the drive using the Start button. Allow the motor to reach its configured commanded speed. 4. Press the Stop button, and count to 5. Notice that the motor does stop after approximately 5 seconds. The drive stayed in control of the motor s speed because the energy was transferred into the dynamic brake resistor at this station. Adjusting Frequency vs. Dynamic Braking As shown above, these two options of bus regulation provide a way to protect the components of the drive. The charts below show a bit more of the differences between them. 14 of 16
Adjusting Frequency The Motor speed (dark green) remains at its configured commanded speed, until given the command to stop. The drive is configured to adjust the frequency to compensate for the increase in bus voltage, so the drive will ignore the configured deceleration time. The DC Bus Voltage (in light green) quickly rises to its configured limit, but stays there until the motor speed reaches 0. Dynamic Braking Again, the dark green line is the speed of the motor. When the command to stop is detected, notice that the DC Bus Voltage in light green increases quickly, but because there is an external resistor configured in the drive, the excess energy is diverted to the resistor instead of the drive. In this case, the resistor handles the energy, protecting the drive components, but also bringing the motor down to a stop in the configured deceleration time. You have completed the Bus Regulation Lab! 15 of 16
Notes Publication CE-DM253-EN-P Sept 2015 Copyright 2014 Rockwell Automation, Inc. All rights reserved. 16 of 16