Cascade Controls Application Spotlight

Communicating and Networked Motor Management

A Value Proposition

Chances are that, without motors, your facility would produce zero revenue. And, as processes and machinery go, a motor that isn’t running is just as productive as no motor at all.

What else in your facility produces revenue? People do. Is there supervision to help ensure productivity? If someone is having trouble doing their job, does a co-worker or manager step in to assist before a complete failure occurs? When the working environment becomes uncomfortable, or dangerous, would changes be implemented? I think the answer to these three questions is mostly, Yes. Without some form of monitoring, worker productivity would likely grind to a halt for a number of reasons.

In this context, motors are not all that different. They have a job to do that can be made difficult by various factors. If ignored for long periods of time, a motor could degrade quality, increase costs or cause your production revenue to stop entirely.

Preventive maintenance and routine motor inspections are, in theory, very common. Record-keeping is an essential part of motor maintenance. My question is how consistent is that effort? And, is there a less costly way to achieve the same end result? A motor diagnostics program with the benefit of full time and automated data logging, programmable alert triggers and integration with the process and operator actions will deliver a much more accurate picture of potential failures.

Know Your Motors

Motors are electro-mechanical devices. You can understand a lot about how a motor is doing by focusing on the “electro” part of that description.

Amps tell you how hard that motor is working.
Amps, as a percent of rated full load, tell how close that motor is to being over-loaded.
Trended Voltage will provide Sag and Swell alarming. Voltage swings can cause rapid heating in the windings.
Imbalanced phase currents could result in premature burning in the windings and may indicate cabling issues.
Voltage phase imbalance will reduce the available torque that the motor can deliver. Even slight variations (2% to 5%) require de-rating and can cause winding damage.
COS Phi is the (“Displacement”) power factor of the motor’s Fundamental voltage and current waveforms. Low efficiency, over-sized and idling motors increase Reactive Power and result in Utility penalties.
Ground Fault indication gives the technician the heads-up on what tools and methods are needed to get back in production (many electronic overloads include GF protection, but do not differentiate trip indication).
Power Factor (“True”) is good to know since “stiffer” systems (higher power factor) reduce losses (loss is proportional to the Square of the current).
Time to Trip is a definitive alert that the motor is going to shutdown.
Number of Starts directly relate to the frequency of maintenance.

Mechanical conditions, that are an important part of any motor diagnostic program, should also be monitored.

Vibration is the earliest indicator of mechanical faults and can be trended to match machine operation.
Winding temperature indicates if the motor is at risk of internal damage. A 10^oC rise cuts lifetime in half.
Ultrasonic signals indicate the health of the entire mechanical assembly – from motor internals to load.

Can you get all of this information from a motor without camping next to it with dozens of probes, meters and test equipment? Sure!

Getting Connected

With the introduction of fieldbus technology in the 1990’s, it became possible to link your motor control to your logic processor and continuously monitor the condition of motors.

Quite a few early adopters embraced that strategy only to find that in some cases the data available at the time was not worth the sacrifice in response time. Or, if response time was not an issue, the users of the data did not have a simple, cost-effective way to interpret and make use of what the system delivered.

I believe the technology of today eliminates all of those issues and delivers significant value. The Simocode Pro motor management system, from Siemens, is one very good example.

With the high speed network, Profibus, as its communication platform, the Simocode Pro enables monitoring of almost every electrical condition with little impact on system response. Here is partial list of the motor information that can be accessed in real time.

Motor State (on / off / tripped / cw / ccw) Phase currents and maximum current Phase voltages True Power Factor COS-Phi – Displacement Power Factor Time to Trip Operating hours Number of Starts / Number of Trips Time & Date stamps Temperature Rise Actual temperature Vibration / Sound / Ambient via analog transmitters	The Simocode Pro is a full motor management device. Besides monitoring and overload protection, it also provides control for reversing, Star-Delta, and Two-speed (including Dahlander). Plus, additional I/O and logic can be added for near micro-PLC functionality dedicated to each motor control circuit.

OEM Engineer: "The SIMOCODE Pro really exceeded our expectations; it does what it promotes and more. It is simple to program and operates reliably in a harsh environment."

Between protective functions, control, operating data, communications, service data and diagnostics there are over 100 monitoring items to choose from. If you have used communicating, solid-state overloads before, you may be wary of the time it takes to configure and link these devices on a network. Siemens has made this task simple and quick. Graphics based software presents all of the functional choices in a clean, familiar way.

Do you have many motors to configure?

No problem, because you can copy a core configuration onto a memory module. Plug that module into each Simocode Pro and you have successfully configured them in about seven seconds each.

Profibus node addressing for each motor is just as easy using a plug-in device.

But it Costs More…What is all this Worth?

I would like to present just a couple of examples of how this technology can add value to your business.

Motor Trip - Overload

There can be no denying that unplanned downtime is costly. Lost production revenue, scrap and cleanup can hit the bottom line for tens of thousands of dollars per hour.

Compare hard-wired motor control to Simocode for an overloaded motor.

This scenario repeats itself many times a year. Often, the actual downtime is significantly higher
due to poor communications between operators and technicians, lack of available technicians and
confusion about the root cause of the motor stoppage.

Having a constant stream of information going to operators, technicians and management will
ensure that when the risk of an unplanned stoppage is identified, everyone will be
prepared to take appropriate action.

Motor Trip – other cause

We could build a similar scenario with the condition of phase imbalance or ground fault trip. These are commonly used options for electronic overloads, even when they are controlled via hard-wire. This complicates matters and can extend the downtime since the cause of trip may not be known. An overload is really a mechanical problem manifested by high motor current. Ground and Phase issues are electrical issues. You would not always use the same maintenance personnel for both and certainly not the same tools and procedures. Knowing the exact cause of a trip, via the Simocode data, will direct what tools and people should be alerted by the operator.

That could easily prevent 30 minutes of downtime.

With these two scenarios, I have identified a potential to reduce downtime by a minimum of 30 minutes for each occurrence. How many times a month is this likely to happen? If we estimate twice per month for a production area, then we are saving 1 hour of downtime. With a production revenue rate of $15000 per hour, that calculates out to added revenue of $180,000 in a year.

$180,000 per year is a pretty good return-on-investment on the added cost of Simocode Pro.

A Simocode Pro unit for a size 2 NEMA motor starter would add about $550 to the control cost of each motor.

The ROI mentioned does not include the reduced installation cost associated with the reduction of wiring, conduit and labor when networks replace individual point to point control connections.

With today's material costs, 15 motors is the approximate break-even point. Above that, the installed cost for networked motor control is less than individual control wiring.

This is an additional benefit to whoever is financially responsible for the installation

Senior Engineer: “..hardwiring would have cost an additional $30,000 in labor and material costs if we had chosen conventional (ie point-point wired) MCCs”

Using Motor Operation Data The amount of data available can be overwhelming. Balancing system complexity with performance and demands on the operator is a challenge. With today’s network communications and operator interface (HMI) technology, the ease of getting value from networked motor control is greatly improved.

Director of Technology: “This was a major benefit for us, you can monitor a lot more detail on the motor status than you can on a conventional control system."

At one time, archiving and trending were the domain of high priced SCADA software. Common databases and communication from one operator panel to another required complex system integration.

HMI software today (like Siemens WinCC Flexible) bring those SCADA-like features to low cost machine level operator interface. For example, archiving motor amps and winding temperatures will provide an accurate sense of how hard that equipment is working over the course of production. Displaying those trends can help the operators keep that process running at maximum efficiency. Sending that data, in real time, to maintenance can help them prepare for planned shutdowns and more precisely anticipate costs. These Trending and Network options are now priced below $200.

These are just a few of the strategies that can deliver the value of networked motor control and management. As part of a motor diagnostics program, networked motor control will help ensure that life cycle costs are reduced and revenue is maximized. Wesco can assist in both the technical system design and the return-on-investment calculations related to the transition from hard-wired motor control to networked, intelligent motor management. Call your Wesco Account Manager for more information.
Paul McShane Regional Automation Program Manager \| Wesco Distribution, Inc 503-221-4412 pmcshane@wesco.com