The key to using intelligent motor control data is to understand what the data represents, how to properly display it, and how to properly use it.
By Bill Martin, product manager, Electronic Overload Relays, Rockwell Automation
All intelligent motor control and protection devices produce a lot of data.
They can produce so much that it can be overwhelming.
You bought these products to help you reduce unplanned downtime for your company, but where do you begin? How can you use this data to justify your investment?
The key to using intelligent motor control data is to understand what the data represents, how to properly display it, and how to properly use it to create meaningful information that will minimize unplanned motor downtime.
There are five types of data, and each data type is collected, displayed, and analyzed differently:
- Real-Time Data.
- Projected Data.
- Operational Data.
- Historical Data.
- Energy Data.
Real-time data is instantaneous information from a motor that a machine or process operator uses to verify that the machine or process is operating properly. This data is being read into a programmable logic controller (PLC) quickly (20-1000ms), and it’s displayed in a human-machine interface (HMI) terminal or a supervisory control and data acquisition (SCADA) system.
Some automation vendors provide prewritten and tested graphics that allow the system integrator to quickly copy and paste these prewritten displays to produce a graphical user interface for an HMI terminal or SCADA system in a matter of minutes for large quantities of motor control devices.
Most users will display RMS current for each motor on their display, but there are two real-time parameters that can provide the operator more useful information — percent thermal capacity utilization (%TCU) and percent full load amperes (%FLA).
- %TCU indicates the heat level of a motor. The motor control device will trip on a thermal overload condition when this value equals 100%. A warning message can be displayed on an HMI when the %TCU is greater than 90% to let the operator know that the motor is getting warm.
- %FLA indicates how much current the motor is drawing compared to the name plate rating. Ideally, this value should not go above 100%. If this value is greater than 100%, a warning message can be displayed on an HMI letting the operator know that the motor is drawing more than its rating.
Projected data is information that should be displayed on demand on an HMI. Two common parameters are time to trip and time to reset.
- Time to trip lets an operator know how long they have until the motor protection device has a thermal overload trip. This information should dynamically appear to an operator viewing an HMI when a time level is reached.
- Time to reset lets the operator know how long the motor needs to cool before a trip reset command can occur. This information should dynamically appear to an operator viewing an HMI after a thermal overload trip.
Operational data is information that should also be displayed on demand on an HMI for maintenance personnel. Parameters such as operational hours and number of starts can act as a “change engine oil” light on a car.
When a set amount of operating hours or starts is exceeded, an information display can be shown to proactively alert maintenance to do their routine procedure.
Another form of operational data is a trip log and snapshot log. This information can be viewed on an HMI or a web browser by maintenance personal when a trip or fault event occurs.
This data allows you to quickly understand the reason for a trip or fault event and the real-time voltage, current and power data at the time of the trip or fault to minimize and troubleshoot the unplanned down time event.
Historical data is information that should be collected every 15-60 minutes in a historical database and viewed via a trend display. Ground fault current, RMS voltage and RMS current should be reviewed weekly to see whether any significant magnitude changes occurred for these steady values. This information would provide insight to any potential future motor issues.
Energy data is information that should be collected every 15 minutes in a historical database and viewed via bar graphs and trend displays. This information should be reviewed monthly to determine when and why peak demands occur and identify opportunities to save energy during non-production time.
Some vendors have software that will automatically e-mail you reports that mimic utility bills and identify loads that contribute to the peak demand.
These five types of data will enable operators to make better decisions when running a machine or controlling a process, allowing them to proactively react to potential problems and more efficiently troubleshoot issues when an unplanned event occurs.
Learn more about Rockwell Automation intelligent motor controls.
Find out about Rockwell Automation graphic terminals.
Learn about Rockwell Automation historical data collection software solutions.
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