Newsletter – Fall 2012
|Cynthia A. Boyd, Director of Sales|
Thank you all for your feedback on our last newsletter. While we continue to add content to our website, we will also attempt to provide you with product updates, product releases and current news in this quarterly update. As you see, this Fall issue highlights a metering application enabled by cellular technology, connecting the ezeio System to our WattNode meter. eze Systems offers both wireless and cellular technology, their contact information is below.
We intend to make it very easy to subscribe to our quarterly newsletter, but also intend that if, for any reason, you can esily unsubscribe
In closing, I thank you for being a valued customer, I personally would appreciate any feedback that you may have as I hope to make this newsletter a valuable and meaningful way for us at Continental Control Systems to keep in touch.
Watt Fore !
The WattNode Modbus Energy meter saves
the rainy day on the green.
Recently a Boulder County golf club member contacted us because line voltage variations were wreaking havoc with the golf club’s irrigation system, the greens were turning brown, and golfers were getting wet. We have all had a bad day on the golf course, but getting soaked by an errant sprinkler system is worse than being out driven by your sister.
Luckily, the golfer happened to be an experienced energy engineer, so he called on us for a recommendation on a monitoring system that could provide evidence of the power problems to the utility company.
In the past, monitoring a utility service at a pump house out in the middle of a golf course without access to a telephone line or internet connection would require a data logger or expensive point-to-point wireless link. The data logger was ruled out because the engineer wanted real-time access to the data without having to travel to the site to manually download the data.
Since the budget was limited, we recommended a low-cost communications gateway product manufactured by eze System, Inc., with a cellular data modem option. The ezeio Controller works with the WattNode Modbus energy meter to continuously transfer detailed electrical measurements to eze System’s secure web servers. Storing the data in the cloud, makes it easily accessible in real-time using any web browser. The logged data is backed up on the server, where it can be retrieved or viewed as historic graphs.
A key feature of the ezeio System is its ability to set high and low alarm thresholds on any of the energy, power, demand, VAR, power factor, voltage, current, or other measurements. If any measurement exceeded its limits, the system can be configured to send an email alert. The utility was given password access to the eze System website, where they could view and graph the pump electrical data at any time.
After reviewing the data, the utility company conceded that there was a power problem and initiated a project to improve service to the golf club
The WattNode Modbus meter is a multi-function, networked energy meter. The WattNode Modbus offers true RMS power, energy and demand metering, plus individual measurements of voltage, current, power factor, reactive power and energy, and line frequency.
Energy monitoring, data acquisition, data storage and access through the internet using the ezeio System solution
October 31 – November 1, 2012
WEEC – Atlanta, GA
On-line registration is available
November 14-15, 2012
GreenBuild, SanFrancisco, CA
On-line registration is available
January 28 – January 30, 2013
AHR Expo – Dallas, TX
On-line registration is available
Free Expo tickets to the WEEC, World Energy Engineering Congress Conference – Atlanta, Georgia Oct 31 – Nov 1 are available:
Passes for Greenbuild (Nov 13 – 15) are also available on-line. Early registration tickets for the expo are $75.
And ……. believe it or not – registration for AHR has begun – the world’s largest HVACR Expo – Dalls, Texas (January 28, 29, 30, 2013).
Continental Control Systems website
News and Press Releases
Product Application Notes
ACT revenue-grade CTs
|FAQs ??? Ask John Browne:|
How do I select the best current transformer (CT) for my application?
The most important thing to remember when selecting current transformers (CTs) for the WattNode energy meters is that they require voltage output (0.333 volt) CTs. Traditional ratio CTs with current outputs (typically 5 amps) can produce lethal voltages and permanently damage a WattNode meter. CCS sells only “safe”, low-voltage output CTs. This type of CT is calibrated to output 333.33 mVac when the current flowing in the conductor passing through the CT’s window is equal to the CT’s full-scale current rating.
CTs are available in different styles, with different window sizes and full scale current ratings. In theory, one could “design” the “best” CT for any given application, but most projects don’t have the time or budget to have CTs custom fabricated. In the real world, “best” means different things in different applications. In practice, the best we can do is to make the best compromise between the best features.
1) Determine accuracy requirements:
For monitoring, such as part of an energy management system, CTs with an accuracy of 1% to 1.5% over the range of 10% to 120% of rated current and with a phase angle error of less than 1.5 degrees are a good choice. For revenue-grade metering, CTs with accuracies of 0.75% or better over the range of 1% to 120% of rated current and which meet the IEEE C57.13 standard such as our Accu-CT® products are recommended.
2) Decide on a CT style: split-core (opening ) or solid-core (toroidal):
Solid-core CTs are best suited for permanent installation and in new construction, with smaller size conductors. Since they resemble donuts and do not have an opening section, installation requires turning off the power, disconnecting the conductor, and threading it through the CT window.
Split-core CTs, which have an opening section, are easy to install accommodate larger conductors and are usually the best choice in existing construction. They can be installed “hot”, without interrupting the circuit. They are available in various accuracy grades, window opening sizes, and current ratings.
For information on available CT styles, refer to the Current Transformers page on our website
3) Select a CT window opening size:
The window size must be large enough to fit around the conductor being measured but not any larger than necessary because they also need to fit between adjacent conductors. The conductor diameter is determined by its wire gauge. Refer to theCT Opening Size vs. Conductor Size page for a list of conductor gauges and recommended CT window opening size.
Services larger than about 400 amps are typically made up of multiple parallel conductors or a single large conductor (bus bar) for each phase. If there are only two wire conductors per phase and they are close together, the required window size can usually be determined by the conductor gauge. When there are three or more conductors, the arrangement of the conductors becomes a factor. Are all the conductors side-by-side in one row or are they arranged in two or more rows with space between the rows? If so, then a large opening CT, as found in our CTB-series, may be the best solution. As an alternative, a smaller CT can be fit around each conductor with the outputs connected in parallel. Refer to “Paralleling Current Transformers” in our Applications of our web site.
4) Choose a full scale current rating:
For best accuracy, choose a current rating slightly larger than the load’s maximum current draw. If the load current is unknown, then you will have to choose a CT current rating based on the amperage of the breaker feeding the load. The breaker current rating is typically 25% larger than the actual circuit load amps, so for best accuracy at the low-end of the range you may want to choose a CT with an amp rating slightly less than the amp rating of the breaker. For example, on a 225 amp panel, a 200 amp CT will give slightly better low-end accuracy than a 250 amp model.
Next newsletter we will discuss accuracies and measurement ranges, revenue grade requirements and ANSI compliance.
John Browne is one of our resident WattNode meter and energy monitoring specialist. He is available by phone or email and is our first line of technical support. He uses his expertise to help you in product selection, product specification, installation support and trouble shooting.
If there is anything that our team can do whether it be order follow up, technical / installation support or explanation of our billing, please do not hesitate to contact us at any time.
Faye Jaramillo – 720-287-8426 (Inside Sales)
John Browne – 720-287-8431 (Applications)
Pat Sawyer – 720-287-8422 (Accounting)
Cynthia Boyd – 720-287-8433 (Sales)