June 2007

In this issue:

~ RxMS's New Services

~ Why is Pre-site Monitoring critical to customer satisfaction?

~ Uni-polar Current: what does it mean?

Waveform of the Month

~ Below is an increasingly common waveform. Can you name the most likely cause? What equipment is adversely affected by this?

Please respond to this email address with any comments or questions

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Prescribing unbiased power and environmental solutions since 1995!

~ RxMS is a well-known leader in monitoring power quality, temperature, humidity, and air purity. Since we sell our service and not just a box, it will save you time and by having the data analyzed by experts, you get sound unbiased advice quickly, which will maximize your time and money. Our experts have written over 11,000 reports and we can quickly prescribe you with a proven solution.

RxMS's New Services for Their Customers

~ Rx Monitoring Services would like to inform you about the implementation of the hyperlink into the emails regarding our Power Quality reports. This new service will be a hyperlink that will be used to download the reports that you need. This will allow you to be able to receive reports quicker and easier and also retrieve the history of the reports that were done in your region in the past two years. Every email with a report will include all the information you need including a password as well as the hyperlink. This will also mean that since there would be no attachment in the e-mail to you, it will take up a minimal amount of space in your mailbox. RxMS hopes that this new process will help save you valuable time when dealing with our reports.

~ A new implementation of RxMS's EPA2000 and EPA1500 monitors now include a USB port that can easily be used to download data using a USB Flash drive to send to Rx Monitoring's Engineers for quicker analysis. No more drivers are needed!

Why is Pre-site Monitoring Critical to Customer Satisfaction?

~ Documenting that the site has met all of the conditions of the pre-site guidelines that your company presents to each customer is critical to future customer satisfaction. By having a baseline data of what the site was on day one will provide valuable information if the site conditions change as the equipment ages. Most high-end electronic based systems are installed by outside contractors who are paid after the installations are completed. Most of the time these jobs are a fixed price, from a competitive bid that is contracted for that particular job. If the site is found to have a wiring issue, and it is done prior to the customer paying the contractor, this item gets fixed immediately. If the contractor is already paid in full for the job, your customer loses leverage and therefore blames you and your company for the extra costs (“Why wasn’t this found earlier?”). So not only does pre-site monitoring save your customer money, it will save you grief in the long run as well as saving you warranty and service expenses. Pre-site installs can also identify problems with the site before equipment is in place so room plans can be planned and updated around anything that needs to be added to the site (e.g. adding power conditioning, ground inspection, etc.)

          

Uni-Polar Current: what does it mean?

~ Approximately 1 in 55 reports that RxMS does for its’ clients uncovers a unique phenomenon that is called “uni-polar current.” This is confusing to some people and they are not sure what it means or if they have to act on it.

~ What causes this and why is it important? What causes it is simple; the front-end bridge rectifier is damaged and allows only current to flow in one direction (either positive or negative). What causes the damage is not currently known at this time. Since many modern systems are manufactured by several suppliers, it is believed that the most common cause of this is a supplier changing parts (due to the lead free solder issue) that turn-out to be not 100% compatible with the original part (but likely still within the spec of the system).  Since the engineers at RxMS have run into this, I’m sure that we are not alone. For instance, we found that one particular component worked great for us but once the lead-free replacement was chosen, the component blew and caused several maintenance issues. Upon further investigation, we found out that the original part was designed to far exceed its specs and our design relied on that. So to get back to the same level of reliability, we actually had to increase our specs for that component.

~ What damage does it cause? Simply put, when you lose or temporarily lose half of the input bridge, the current on the other half increases in amplitude and time duration. So the component is seeing a larger peak current for a longer time duration then it was originally designed for. This greatly increases the heat in the components and since there are I² R losses in the components, it increases the chances of overheating and eventual component failure.

~ How do I find the cause of the uni-directional current pulse, and what can be done about it? A full engineering investigation needs to be done to look for this type on current draw. This is one of more than a dozen reasons that monitoring both the current and voltage is required during system testing. If such waveforms are found, then corrective action can be immediately taken to insure minimum system downtime.

~ How to deal with uni-polar current?: First investigate the production lot and see if there are similar failures in that lot or if there was an ECO (Engineering Change Order) around the time of the manufacturing date (or the replacement pat date if that applies).  Review the service history and notify the local engineer to keep taps on any replacement parts. Many times the uni-polar current is not a problem at the time it was detected but often it is an indicator that future parts will have to be replaced. Discuss it amongst the engineering groups and develop a plausible course of action (e.g. could be as simple as have a part readily available to the local engineer so that you don’t have excessive customer downtime or have to expedite a part the same day). The key thing is to be prepared and discuss the proper course of action.

Below is a example of a waveform with uni-polar current that RxMS found at one of sites: