Applying and Commissioning PM Motors with the … the example of how to find a motor data sheet on the Baldor Website. How to find the Data Sheet Baldor Website – Select the Catalog
Welcome to the webinar. This is number 26 in the series and once again the subject is Permanent Magnet Motors. This time the emphasis will be on applying and commisioning PM motors with the ACS880 drive. For those of you who are joining us live, please type in your questions along the way and then we will organize them and adress them at the end of the presentation as time permits.
Applying and Commissioning PM Motors With the ACS880 and Other ABB Drives
Speaker name: Rick Akey
Speaker title: Senior Application EngineerLow Voltage DrivesDiscrete Automation and Motion Division
My name is Rick Akey. I am a senior application engineer here at ABB in New Belin, WI. My background is in Electronic Engineering and have worked for a distributor of electrical wire and cable, a motor manufacurer, where I was their drive specialist, and also for manufacturer of line reactors, harmonic filters, EMI/RFI filters and long lead filters. I started with ABB almost 14 years ago in Technical Support before joining Applications Group.
Objectives
By participating in this webinar, you will: Understand the advantages of Permanent Magnet
Synchronous Motors over standard induction motor designs
Know which ABB drives will effectively operate Permanent Magnet Synchronous Motors
Be able to determine what motor data is needed in order to correctly set-up an ACS880 for a Permanent Magnet Synchronous Motor application
Know how to find the motor data listing for Baldor motors using www.baldor.com
Determine how to calculate required information even if it is not listed on the motor nameplate
Identify possible problems to avoid when using ABB Drives with Permanent Magnet Synchronous Motors
So, some of the things we will looking at are: The advantages Permanent Magnet Synchronous Motors can offer in an application. Finding out which ABB drives work with PM motors. Learning what data is needed and how to get it so we can commission the ACS880. And identifying possible problems that so they can be avoided.
There are different types of PM motors, some are DC and of the type fed by SCR controllers, but they will not be a part of our discussion. Some need to operate from a controller that produces a triangular waveform, also not something we will be discussing, but an example is the DC Brushless Motor. The type of motors we will be look at are the type that would make a sinusoidal waveform if you rotated the shaft mechanically. Unlike standard induction motors that need slip to cut lines of force between the rotor and the stator to produce torque, a Permanent Magnet Synchronous Motor’s rotor turns at the same speed at the stators rotating magnetic field. So, Why would anyone want to use a PM motor? More efficient High torque versus size Good at lower speeds with high torques…can eliminate the need for gearboxes Speed accuracy Cooler operation
All of our AC drives work with PMSM motors - - - but in Scalar Mode. This could be ok for some applications or for test purposes, but most applications would be run with an open loop feedback like Vector or Scalar control. The key drives to use with PMSM are the ACS355, ACS850 and ACS880. The standard firmware will allow PMSM. Point out that the ACS800 will allow PMSM but only with a resolver and with the Plus code +N679.
What Are the Challenges
Getting correct motor data: Seems to be impossible with some motors
Nameplate almost never has all of the required data
Often necessary to request some data from the Manufacturer
Always best to confirm the data is available and to be sure the motor will work with the drive before taking an order
Data is usually not what we want, but quite often all we get
In many cases, motor data lacks some key information (e.g Nominal Voltage). Therefore, you most likely will have to consult with the manufacturer to extract the required data. (We can do some calculations and that process is discussed later in this module.) Strongly suggest that it is always best to confirm motor data with the manufacturer prior to booking the order. At the very least, ABB Application Engineering can assist as they have details on specific motors that work well with specific drives.
Here is an example of a Baldor PMSM motor – and what the nameplate would look like. Notice there are slight differences between a standard induction motor and a PMSM (e.g. Rated Bus Voltage, Peak Current, Torque Continuous Stall and Current Continuous, etc.). Notice that “Nominal Voltage” and “Nominal Frequency” are missing - - - items that are listed on a standard induction motor. Well…we got part of what we need…..
How to find the Data SheetBaldor Website
Go to www.baldor.com and enter the catalog number, from the motor nameplate, into the PRODUCT QUICK SEARCH - For example BSM63N-375RA…
Indicate the values that are normally listed on the Data Sheet. The “Voltage Constant” and the “# of Poles” are two items needed to calculate Nominal voltage and frequency.
But if you try sometimes, well you just might find. . .…. You need to calculate – Nominal Voltage
Nominal Voltage Defines as open circuit Back EMF at rated speed
Nameplate gives Rated Bus Voltage only
Find a Voltage Constant (V/ Krpm) on Motor Datasheet What you want is Vrms L-L
(sometimes what you get is: Vpeak or Vrms L-N)
Sometimes it is expressed as: V-sec ( V / (rad/sec))
Review this example of how to calculate “Motor Nominal Voltage.” As stated, what is more common on the nameplate is the “Rated Bus Voltage.” The good news is that “Nominal Voltage” can be calculated by following the formula stated.
But if you try sometimes, well you just might find . . . .…. You need to calculate – Nominal Frequency
Nominal Frequency Not usually given on the nameplate
Find Number of Poles or Pole Pairs on Motor Datasheet
To calculate the Nominal Frequency: Freq = Speed * Poles / 120
Review this example of how to calculate “Nominal Frequency.” As stated, what is more common on the nameplate is the “Max Speed.” Therefore, you need to go to the motor data sheet and find the “Number of Poles” or “Pole Pairs” and use that value along with “Max Speed” to calculate “Nominal Frequency” using the formula stated.
Getting Correct Data for Commissioning an ACS880with an RPMAC TM Motor from the Nameplate
Here is an example of a Baldor RPM AC motor. The nameplate has most of the information we look for. Notice that “Nominal Voltage” is missing though. Well again…we got part of what we need…..
Note the data entered based on the nameplate information and the motor data sheet. Discuss the preference of doing an advanced ID run and note that this is a 4 pole motor based on the calculated motor pole pairs having a value of 2. (1800 X 4)/120 = 60Hz
Group 98 Parameters that are Populated After the Advanced ID Run is Completed
Low inductance motors when using the ACS800 - Causes ripple to current and torque due to low switching frequency. Can trip the drive on a Overcurrent and/or overheat the motor. Some possible problems are: motor will not run or hold speed, or may run rough with cogging. Drive trips on Overcurrent or pulls high current with no rotation. Operating above base speed – Because of the back EMF, over speeding leads to overvoltage, which may damage the drive. May need to raise switching frequency, This helps reduce ripple current. If controlling the motor without feedback, it may rotate at start (e.g. oscillate forward & reverse). This is the drive has to align the magnets with the stator windings. Limitation to field weakening due to back EMF. What is the limitation? Because of the back EMF, over speeding leads to overvoltage, which may damage the drive. Zero speed operation at high currents need an oversized drive.– At zero speed the drive is putting out pure DC, this will keep one IGBT on instead of rotating through all three. Oversizing the drive will keep from overheating the IGBT.
PM Motors for ABB DrivesSummary
All ABB Drives can operate in “Scalar” if required
Certain ABB drives lend themselves to effective use of PM motors – specifically the ACS355, ACS850, and ACS880 (encoder is not required)
The ACS800 requires special PMSM firmware (+N679) and always needs a resolver
Getting correct motor data can be a challenge: Nameplate almost never has all of the required data
Usually have to request some data from the Manufacturer
Other concerns include: Low inductance motors with the ACS800, operation above base speed, the possible need to alter switching frequency, shaft oscillation when using a drive without feedback, limitation to field weakening due to back EMF
