FAQ: Is it possible for an AC induction motor, driven by a Yaskawa V7 inverter to "follow" a Yaskawa Sigma II servo system using the Servopack's (SGDH) encoder output and the Inverter's "reference pulse" (RP) input?
Breadcrumb
Contact Us
contactUsAction
Yes it is.
The V7 has a "reference pulse" (RP) input that accepts a pulse frequency as a speed command, and drives the AC induction motor at a proportional speed (reference frequency.) The speed at which the AC motor follows the servo system depends on digital settings in both products. An excel workbook is provided to test both Servopack and Inverter settings before they are actually applied in the two products.
Servopack and Inverter Settings:
Since the Servo system is commanding pulses to the inverter, the servomotor speed and the value set in the encoder dividing parameter of the Servopack (Pn201) directly effects AC induction motor speed.
In order for the inverter to accept the pulse command from the Servopack, the RP input for the inverter must be active (n004 = 5). Inverter parameter n149 scales the "command frequency" to "reference frequency".
The other limiting factors in the inverter are the minimum frequency the inverter commands and maximum frequency settings. The minimum frequency reference of this inverter is 1.5Hz. The maximum frequency is the set value in n011, and is commonly set at 60Hz. It must also be noted that only one of the two channels of the Servopack's encoder outputs are used to command the inverter. The dynamic speed range of the AC induction motor (1.5 ~ 60Hz) driven by the inverter is the limiting factor in this system. However, it is also true that the settings in both the Servopack and the Inverter affect the final speed of the AC induction motor. Due to this dependence of the settings in both products, along with the common requirement to obtain reasonable dynamic range of the AC induction motor, an Excel workbook ("Servopack Master V7 slave.xls") is made available.
Using the workbook:
The workbook has two spreadsheets. One includes the instructions, the other (Servo-Inverter tool) will predict the resultant reference frequency speed of the inverter driven AC induction motor. The user needs to provide the "Servo-Inverter tool" spreadsheet with the digital settings of both devices, and the speed of the servo system.
This spreadsheet has yellow colored cells where the servo system speed and the parameter setting of each device are entered. The results, displayed in bold blue characters, include the frequency command of the Servopack's pulse output and the frequency reference generated by the inverter to the AC induction motor.
A sample connection is attached to this document (.JPG) and also included is a drawing of connections with tested device settings.
SAFETY PRECAUTIONS AND INSTRUCTIONS FOR USE OF FAQ INFORMATION!
Please read and understand the product instruction manual before installing, servicing or operating Yaskawa products. FAQ content and illustrations are provided as technical advice to augment the information in manual, not supersede it. It is not possible to give detailed instructions for all types of installation or support activities. The information described in the FAQs are subject to change without notice to improve the product or FAQ. Yaskawa assumes no responsibility for errors or omissions or damages resulting from the use of the information contained in any FAQ. All warnings, cautions and product instruction for product use must be followed. Installation, operation and maintenance should be carried out by qualified personnel. Failure to observe these and other precautions highlighted in the product manuals will expose the user to high voltages resulting in, serious injury or death. Qualified personnel are defined as individuals who are familiar with the installation, starting, operation and maintenance of Yaskawa products of the type described and have proper qualifications to perform the work.
Phone
If you have an urgent request, please call: 1-800-YASKAWA (927-5292) or 1-847-887-7000.Electronically
To contact us electronically, please select your type of request and complete the form.Yaskawa America, Inc. - Drives & Motion Division
2121 Norman Drive South
Waukegan, IL 60085