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  • Zenith automatic transfer switch manuals

    Hey everyone, has anyone seen an ATS like this? And can you help find a manual? I can’t find one

    Posted by eric_bunnell on 03-23-2025
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    Practice question "Which SCADA communication is only appropriate for short distances?" should have RS232 as the correct answer; however, this was marked incorrect with "CAT6" as the correct response. RS232 is a serial, point-to-point communication method only intended for distances up to approx. 50ft whereas CAT6 is typically used with Ethernet communicatio...

    Posted by user987 on 03-15-2025
  • Insulation Resistance Testing Open Circuit Breakers

    Hey everyone, when doing insulation testing on circuit breakers. When I test the breaker open, I typically just go from line to load. And I am not grounded out the other poles In this book, Paul, Gill‘s electrical power, equipment, maintenance, and testing it is saying for circuit breakers open connect high voltage lead to pull one. Ground all other po...

    Posted by eric_bunnell on 03-13-2025
  • Report Tech Quiz Issues Here

    [Transformers] **1. A wye-delta transformer has a primary line voltage of 7200 V and a secondary voltage of 360 V. What is the turns ratio?** *Your Answer: 20:1* Correct Answer: 11.55:1 Help: [What is the turns ratio?]

    Posted by user988 on 03-07-2025
  • RTS Meter Test for SEL-851

    I don't have the SEL-851 in my .mdr database, but based on the issue you're having, I'm pretty sure it has to do with the window position numbers in the METER.TXT read. I haven't figured out yet how to identify the correct number for the position I want except by trial-and-error. If you want to fix it so that you don't have to run manual every time for thi...

    Posted by user987 on 03-07-2025
  • FT Switches - Voltage on blade or not?

    To me, it's about the purpose of the test switch... in my experience, they're mainly used for isolating the relay(s) from the system. If you're planning to test the relay(s) after this isolation, and you would like to use test paddle(s), the tops (stationary terminals) are the only things connected. Makes things way easier to test.

    Posted by user987 on 03-07-2025
  • Restricted Earth Fault Element

    Yes. The main thing to remember for the REF element is the polarizing quantity the respective element needs to operate. For example, REF1 may be from the xfmr neutral CT comparing against one of the High-side breaker CTs. Therefore, you'll need to inject current from each of those CTs in order to properly test the REF element. There is a good REF Test se...

    Posted by user987 on 03-07-2025
  • Remote Bits on SEL 351

    Yes, remote bits can be programmed to follow Set, Clear, or Pulse. It sounds like your control center is sending a Set command for the remote bit instead of a pulse command; therefore, the RB1 stays a logical 1 until it receives a Clear command. I'm guessing you're using DNP3.0 comms from the command center to this relay? If so, check that the binary outp...

    Posted by user987 on 03-07-2025
  • Circulating Current in Two Transformers on Different Taps

    First, identify the voltage difference from a one-tap step: 5/8% = 0.00625pu V = difference * vsec/sqrt3 V = 0.00625 * 13.8/sqrt3 V = 49.796 Then find base xfmr impedance: Z(base) = KV^2/MVA Z(base) = 13.8^2 / 12 Z(base) = 15.87 ohms So that you can now find the loop impedance: Z(loop) = 2 * Z(xfmr) Z(loop) = 2 * (9%*Z(base)) Z(loop) = 2 * (0.09 * 15.87) Z...

    Posted by user987 on 03-07-2025
  • NICET Study Resources

    I am studying for the Level 1 Electrical power test as well. Besides rote memorization any other study guides are greatly appreciated.

    Posted by Accurate87 on 03-04-2025
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    Posted by TestGuy on 03-04-2025
  • Remote Bits on SEL 351

    Is there a way to make remote bits a momentary pulse. We have an output in parallel with a pushbutton in the panel going to an input of the relay to reset an under frequency trip. But when our control center sends a reset the output which equals RB1 latches in stays high. This prevents a future UF TRIP.

    Posted by Starttheshow on 03-03-2025
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