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Casey Heater

What is Arc Flash? - 1 views

  • NFPA 70E-2000 or IEEE Standard 1584-2002
  • use of fuses, particularly current-limiting types, but as will be shown below, they are not always the answer
  • The overall result is that the short circuit values are always calculated on the high side. When doing a short circuit analysis for sizing the interrupting capability of protection equipment, this is the best practice. But, it is not the best practice when evaluating equipment for Arc Faults and establishing PPE requirements. This is extremely significant, and quite non-intuitive, situation.
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  • Current-limiting fuses often do provide additional protection and they are very good devices but they must be applied properly. In this example, the circuit breaker provides the best protection.
  • a relatively small change in calculated bolted fault current has a major effect on the calculated arc fault current.
  • as the calculated arc fault current is reduced, the clearing time increases, resulting in the incident energy level increasing and thus, the PPE requirement increases.
  • 2. A reduction in bolted fault current and thus a reduction in arc fault current can actually result in a worse situation. In the motor example above an arc fault current reduction from 4000 amps to 1800 amps resulted in an increase in arc fault energy from 0.6 cal/cm2 to 78.8 cal/cm2. Exactly the opposite one would expect before doing the math. In terms of the above example coordination curves, this occurs because the arc fault current moves from the instantaneous portion at the bottom of the coordination curve to a point higher up, incurring a the time delay before the device trips.
  • Categories of PPE as described in NFPA 70E are: Category Cal/cm2 Clothing 0 1.2 Untreated Cotton 1 5 Flame retardant (FR) shirt and FR pants 2 8 Cotton underwear FR shirt and FR pants 3 25 Cotton underwear FR shirt, FR pants and FR coveralls 4 40 Cotton underwear FR shirt, FR pants and double layer switching coat and pants
Casey Heater

Short Circuit Current Ratings for Industrial Control Panels | Automation World - 0 views

  • UL508A. Per Section SB, the overall panel SCCR can be determined using the following steps: Establish the SCCR of individual power circuit components as specified in SB4.2. Modify the available SCCR within a portion of a circuit in the panel due to the presence of current limiting components as specified in SB4.3. Determine the overall panel SCCR as specified in SB4.4.
heibau

4-20mA scaling calculator - DIVIZE industrial automation - 0 views

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    Easy to use online 4-20 mA scaling calculator, Calculates process value from loop current vice versa.
heibau

4-20mA current loop tester, 10-turn potentiometer, panel-mount - DIVIZE industrial auto... - 0 views

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    4-20 mA current loop tester for 2-wire and 4-wire 4-20mA current loop panel-mount, 10-turn potentiometer.
heibau

Namur NE43 - DIVIZE industrial automation - 0 views

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    Description of the Namur NE43 recomendation for 4-20 mA current loop sensors.
Casey Heater

pvbrowser - The Process Visualization Browser. HMI and Scada for every platform. - 0 views

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    Open source process visualization.
Casey Heater

Kinetix Drives Comparison - 0 views

Casey Heater

Rockwell Automation ControlLogix « Digital Bond's SCADA Security Portal - 0 views

  • ODVA has not even begun an effort to add basic security to the protocol.
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    Control-Logix Vulnerability
Casey Heater

https://www.blackhat.com/presentations/bh-dc-08/Larsen/Presentation/bh-dc-08-larsen.pdf - 0 views

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    Breakage Presentation
Casey Heater

http://www.parkermotion.com/whitepages/Anti-Cog_Application_Note.pdf - 0 views

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    A description of Anti-Cog Technology
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