-Rajesh Tiwari, Jouni Seppala

OMG Kokkola in Finland is the world's leading producer of cobalt-based specialty chemicals used primarily in batteries and hard metal cutting tools. Because of these extremely sensitive applications, the company's cobalt powders must meet very high-quality standards. Imagine the resulting disaster if a laptop battery exploded in an airplane!
To keep its systems current, OMG upgraded the automation system for its cobalt chemical line in 2006. One important part of this upgrade was the modernization of its low-voltage Motor Control Center (MCC). To enable full exploration of the maintenance improvement possibilities, the company chose ABB's MNS iS, an Integrated Motor Control System (IMCS) Equipped with smart sensor measurement, MNS iS can measure current, voltage and temperature and provides a wealth of information. Most significantly, it enables the use of information for comprehensive condition-based maintenance practice.
At OMG, the use of sophisticated smart instruments and intelligent MCCs was quite common. There was a lot of information already available however, it was not resulting in maintenance improvement as anticipated. The distinctive constraints were as follows:

• Routing of information
  The information available through the smart equipment was routed through the Distributed Control System (DCS) controller - regardless of its relevance - thereby degrading the controller's performance and negatively impacting critical plant control applications. The role of the DCS controller needed to be focused on process control rather than on information management.
• Information relevance
  Information not related to process operation was being directed primarily to the process operators, who had little use for it.
• Information utilization
  Site operators were lacking specific instructions about what actions to take and could not independently interpret the information for necessary corrective measures.

Information can only be meaningful when it is directed where it is valued, understood and utilized. A single unified environment that could present the right information to the right operator at the right time would be essential for the practical use of information at the site.
OMG Maintenance Practice
The maintenance practice at OMG could be broadly classified into two categories, preventive and corrective.

Preventive Maintenance
Preventive maintenance consists of regularly scheduled maintenance inspections during which a complete overhaul of all equipment is made, regardless of its true need. It is the most common maintenance for field instruments, motors, valves, pumps, etc  and serves as an insurance against potentially costly breakdowns during operation. The prevailing rationale for employing this inefficient maintenance method is the lack of factual data that quantifies the actual need for repair or maintenance of plant machinery, equipment and systems. Maintenance scheduling at OMG was often based on previous experience or on actual equipment failures. The most disturbing fact, although maintenance occurred regularly, there was still no guarantee that the equipment would not break down between inspections.

Corrective Maintenance
Corrective (or reactive) maintenance is performed only after a failure has occurred. It is normal in process dynamics that production may be interrupted by trips or overloading  while undesirable, these issues can be resolved. The challenge however is when the equipment itself breaks down and replacement parts are not immediately available.

Asset Monitoring for IMCS Maintenance
Traditionally, LV constant-speed motors were not thought to greatly impact the overall plant availability, however, most of the plant shutdowns can be attributed to them. A trip on any such motor or a fault in the operating motor starter in the MCC was enough to halt a process. ABB's asset monitoring technology for MNS is was deployed at OMG to explore the maintenance effectiveness possibilities in the area of low-voltage (LV) IMCS.
Asset Monitor is a software component that gathers data from various sources, brings it into the context of the asset and evaluates the information conditions are assessed, possible degradation detected and remedies proposed. A fault report is subsequently delivered to personnel equipped to act upon the information.
Asset Monitor runs directly on the DCS platform, ABB's System 800xA, which is already available in the plant. The information collection and presentation is depicted in Fig 1. MNS iS provides a fieldbus interface for process-oriented data exchange and control to the DCS controller. All other electrical and maintenance-specific information is directly routed via an OPC (OLE for Process Control where OLE is Object Linking and Embedding) server, installed directly on the DCS operator station PC server. The asset monitoring workstation provides an exclusive workplace for maintenance purposes. Maintenance personnel can log in based on their specific roles (eg technicians) and view the pertinent information.
Inside the workplace there are four different structures through which to navigate. All structures serve as aids and their usage depends upon the operator's needs.

Control structure
All IMCS in various electrical substations are shown and navigated through based on the communication structure.

Location structure
This depicts the locations of all the IMCS in the plant.

Asset structure
Here, the IMCS structure is divided into IMCS name followed by the grouping of motor starters based on the control schematics (eg, DOL, RDOL).

Documentation structure
All the relevant IMCS documentation can be accessed through this structure.
Within these different navigation structures, there are several maintenance- oriented faceplates and display structures for all IMCS motor starters. These displays are accessible from all four navigation structures and are described in Factbox1.

IMCS Motor-Starter Asset Monitor
The motor-starter Asset Monitor gathers the actual usage data on motors,contactors and motor-starter contactsfor condition-based monitoring, whichare used to predict the necessary maintenance. The Asset Monitor distinguishes among equipment that is

• Under continuous operation without switching
• Rarely operated or not used within a specified time
• Under capacity or over capacity for pertinent maintenance

The Asset Monitor also continuously evaluates all events, alarms and trips for specific maintenance and essential working issues. It groups these conditions into electrical, mechanical, operating and process-related categories. This categorization makes it possible to identify and direct the information to the appropriate maintenance operator, who can take the necessary action. These conditions are further categorized into subconditions with severity levels showing the degradation of asset performance for quick identification and operator action.  A right click on the conditions in Asset Monitor opens a new window with the fully analyzed problem or condition, and answers the following questions

• What/where is the problem?
• What is the type and severity of the problem?
• How was the problem caused?
• Who is the appropriate operator to initiate action (ie, Is the issue operation or maintenance-related)?
• What specific actions are needed to solve the problem?
  If an emailing or SMS service is enabled, the fault report is directed to the right operator to initiate resolution of the problem.

Motor-Starter Maintenance Faceplate
A motor starter faceplate supports the elecrical operator. The faceplate also contains all measured values and status information for online monitoring. In addition, it enables the resetting of special maintenance-oriented fault conditions. These are as follows

• Too many thermal overload (TOL) alarms
• Too many TOL trips
• Too many start limitation alarms
• Too many start limitation trips
• Insertion cycles

Furthermore, Asset Monitor also supports national languages, and the asset monitoring software package uses the colors, symbols, nomenclature and layout specified by NAMUR International Association of Automation Technology users in the process industry (NAMUR) guidelines.

Asset-Monitoring-based Maintenance
The MNS iS IMCS provides a great amount of information and maintenance data. Asset monitoring software then puts this data into context for the maintenance operator. The IMCS, for example, is based on withdrawable motor-starter technology where the number of insertion cycles of motor starters does matter. When the number of insertions on a particular module reaches a set number of cycles, electrical contact maintenance is required. This ensures an optimum electrical contact connection and contact pressure for optimum motor-starter operation during the life cycle.
A similar condition-based monitoring is performed by continuously measuring the contact temperature for quality deterioration of the cable connection. Asset Monitor also performs operation supervision and identifies motors or equipment that have been in continuous operation to raise specific maintenance issues. It also checks that the motor starters are placed in a designated compartment after maintenance.  Additionally,  it performs a continuous check on all internal components, their consumption and lifetime calculation, and informs the operator about their health status, maintenance or replacement planning. All such conditions are constantly monitored and evaluated by Asset Monitor. The maintenance issues are categorized as electrical, mechanical, process and operation related and are then directed to the appropriate maintenance team. Just as operators are notified when maintenance is necessary, so are they warned when the conditions require proactive response. The warning criteria, the time delay before the trip occurs and the trip severity are all configurable on every fault, safety or motor-protection function. Most importantly, the thermal capacity is continuously tracked for all motors. If a motor is operating under overload conditions, then Asset Monitor dynamically calculates a precise time at which the motor may trip, notifying the monitoring operator and initiating a corrective action. When the trip is imminent, all measured values (including the trip current) are logged for post-analysis, and a detailed report is generated for faultfinding. These online working or maintenance issues are calculated on the basis of current, voltage and temperature measurements by the IMCS.
The systems also tracks general conditions that can be defined by the user. For example, when monitoring external conditions related to motors or process interlocks, the condition details, cause, severity level and suggested actions are user-defined.

OMG Expectations and Assessment
Asset monitoring provided an opportunity to improve the prevailing maintenance situation at OMG. The goals and results of the implementation follow.

Additions, Modifications and usage
The main consideration in establishing the asset-monitoring program was maintaining the existing DCS structure and process control task. There was to be no additional programming in the DCS controller and the process-control operation was to be undisturbed -ie, the system should not require modifications in order to work. The asset-monitoring program should be easy to acquire, easy to operate and accessible from day one.
This expectation was met. The information gathering from MNS iS was performed in real time and the data was directly routed to the operator without passing through the DCS process controller.

User-Friendly System
OMG expected the maintenance information generated by Asset Monitor to be clear and user-friendly - working with the system should not require specific expertise.
To become familiar with, adopt and utilize the system, training was necessary for the maintenance technicians. OMG found the system to be technician friendly.

Plant-wide Maintenance Workplace
OMG required that all maintenance activities for connected switchgears be performed on the same platform, with no switching of applications. The same platform was also to be extendable as a unified platform for plantwide maintenance at a later date.
All MNS iS switchgears at the OMG site were connected to the asset monitoring platform. All other ABB-supplied plant equipment and process instruments can be connected to the same platform in the future. ABB offers generic Asset Monitors for third-party equipment but it would be necessary for OMG site personnel to configure them.

Maintenance Practice Improvement
The most important objective was that the asset-monitoring program should substantially reduce maintenance requirements and improve the IMCS performance. Asset monitoring cannot be interpreted as a substitute for the traditional preventive or reactive maintenance management methods at OMG. It can, however, be a valuable addition to a comprehensive, total plant maintenance program. How asset monitoring can complement traditional maintenance practices is shown in

Preventive maintenance is time based and is performed at regular intervals. Predictive maintenance must also be performed regularly, but the intervals are need based; ie, they can be shorter or longer. The duration of maintenance time differs, however,  with preventive maintenance this can be comparatively longer as maintenance is performed on all equipment; with predictive maintenance this can be shorter as maintenance is performed only as needed. Most importantly, preventive maintenance is precautionary and is performed regularly and yet it cannot always prevent a catastrophic shutdown when maintenance is required between two scheduled intervals. This is precisely where the online condition monitoring in Asset Monitor comes in, since the visualization of key plant information and asset performance are continuously under the radar of maintenance personnel.
Asset monitoring cannot eliminate reactive or fix-on-failure corrective maintenance. It can, however, effectively aid in warning operators of developing conditions so that corrective actions can be initiated before a breakdown occurs. When a trip or fault happens, this monitor can help in quick identification of the problem, directing any technician through the fault-resolution process. Though it would not eliminate tripping or faults completely, asset monitoring would greatly reduce the Mean Time to Repair (MTTR) in reactive maintenance.

A Good Predictor
The premise of ABB's Asset Monitor technology is that continuous monitoring of an asset's actual condition will ensure an accurate prediction of maintenance interval, thereby reducing the probability of asset failure between maintenance intervals, improving the availability and health of the asset and increasing the overall availability of operating plants, all while reducing maintenance costs. It enables, in a sense, a condition-driven preventive maintenance program.
Additionally, Asset Monitor helps reduce spare parts inventory by providing ample time to order replacement parts. Prevention of unplanned failures and early detection of incipient asset problems can only increase the useful operating life of plant equipment. As the asset's consumption is also monitored, the tool can aid in deciding whether replacement of the asset is more viable than repairing it.
The DCS controllers are provided with only process-related data for process control and interlocking, making the process-control communication fast and pertinent. The controller can utilize this data for more effective and critical execution of process-control loops. And the different operators can access the information of interest and act on it directly. This setup also reduces the latent time between process and maintenance operators.
A well-implemented and exercised condition monitoring maintenance practice should enable a reduction in unnecessary maintenance and downtime, higher performance and lower maintenance costs. Most importantly, it should optimize all aspects of an asset's performance

Rajesh Tiwari
ABB Switzerland Ltd Zürich, Switzerland rajesh.tiwari@ch.abb.com
Jouni Seppala
ABB Low Voltage Systems Vaasa, Finland jouni.seppala@fi.abb.com