Our special introduction price for Dranset is $300, but if you purchase it before November 30, 2008 and either:

 

1. Purchase an upgrade from DV5 to DV6 Enterprise, you can get both for $500 (additional savings of $100 from the already discounted DV6 Enterprise special price of $300)
   
    
2. Purchase an upgrade from DV6 PRO to DV6 Enterprise, you can get both for $500 (again a savings of $100)
   
    
3. If you've already purchased the DV6 Enterprise upgrade since August 20, 2008, you can purchase Dranset for $200 (again, a savings of $100)
    

Harmonics: Understanding Equipment Susceptibilities & Needs

A wise and knowledgeable colleague made a presentation at an IEEE Power Engineering Society meeting recently and stated that we really don't need to have all this precisely aligned, continuously sampled and calculated harmonics to get an accurate picture of what the average harmonics are. And since the primary concern in most situations with harmonics is the heating effect in motors, transformers or wires, the average along with the maximum value are a good indication of what is going on in that application. To be a bit more accurate, one could certainly throw in the 95% cumulative probability number, which states that 95% of the time, the harmonic value will be equal to or less than x%.

After noticing an increase in the voltage harmonic levels at a manufacturing facility, a comparison of the data from two instruments that happened to be both monitoring the service entrance was made. One was an IEC 61000-4-30 Class A instrument, which took over 13k harmonic measurements over the 3 month measurement window, each one precisely aligned to tens of milliseconds of the 10 minute boundaries. The other instrument was a much older instrument and had under a thousand measurements. Yet, when the results were reviewed and analyzed, both instruments had the exact same average (2.7%), same maximum (5.0%) and same 95% cumulative probability (3.6%).

This is meant to say that instruments shouldn't comply to measurement standards, as getting the repeatable and accurate results from different instruments is a plus. It does say that "more is not necessarily better or even needed". One needs to understand what the equipment susceptibilities are and what is required from a measurement perspective to see if that equipment is being adversely affected by the electrical environment.

Next month, we will revisit this case study and hopefully get back to the original intention of it, to find out why the average Vthd has increased 10% in a year over the same period of time. See you next month!

MULTIMETER FALLing PRICES

This fall (10/1/08 - 12/31/08) you can own a brand new Dranetz-BMI DranTech Series and/or PL10 multimeter for a lot less money then before. For the final three months of 2008 you can buy our multimeters (kits/packs/solo) for these outrageous prices:

 

Now you can get our full line of multimeters and our most popular units (PL10, Outdoor and PMIT) at a fraction of its original cost. To make it easier to purchase, we are working and offering these special priced multimeters through these four distributors:

 Davis Instruments    Grainger    Tequipment    Test Equipment Connection

They are ready to take your order and honor these special prices, starting Wednesday, October 1, 2008 (can't wait - contact our home office, 800-372-6832 x 369 and talk to Pat Guarraci). Give them a call and get Safety, Accuracy and a great price on a Dranetz-BMI multimeter.