Hfc - Study guides, Class notes & Summaries

Maintenance Tech 2-3 Conventional - NCTI In a hybrid fiber/coax HFC fiber optic node, what are common voltages produced by DC power supplies? - ANSWER-Common Voltage includes +5, +12 and +24 VDC Why do many optical nodes accept two independent power supplies? - ANSWER-For redundant Powering of the node. What is an option available on most optical nodes for connectin to the power supply? - ANSWER-Through a power cable that is connected from the power supply directly to the power port of t...

What is one of the differences between tree-and-branch and hybrid fiber/coax (HFC) DESIGNS? - Bandwidth in the downstream path. In the tree-and-branch design, the cable signal in the downstream path leaves the trunk at the bridge amplifier. There, It makes a transition to the feeder's domain, and the signal splits. What is the maximum number of output ports the split signal can be routed to? - Four. Which of the following statements accurately describes the relationship between coaxial cab...

HFC-152a is ___ - Correct Answer flammable What are the 2 types of HFC-152a systems? - Correct Answer Direct expansion and secondary loop type Direct Expansion - Correct Answer Refrigerant directly expands within the evaporator that is located inside the passenger compartment Secondary Loop (Open Loop) - Correct Answer A circulating non-flammable fluid replaces the evaporator which provides isolation between the flammable refrigerant and the passenger compartment Section 609 of the C...

Ozone depletion is caused by _______ in HFC refrigerants. - Answer-chlorine CFCs and HCFCs ________ making them capable capable of reaching the stratospheric ozone layer. - Answer-do not dissolve in water or easily break down in the atmosphere According to the Rolanda-Molina theory, ________ are destroyed by each chlorine atom in the stratosphere. - Answer-100,000 ozone molecules The stratospheric ozone layer protects us from _______. - Answer-ultraviolet radiation from the sun Which...

When two or more refrigerants are mixed, what must be done with the mixture? Send off-site to EPA certified reclaimer for reclamation or destruction Which SAE Standard(s) must be referred to on the label of approved HFC-134a refrigerant recycling machines? SAE J2210 or SAE J2788 When it has been determined that an A/C system has a low refrigerant charge, what should be done? Perform a leak test procedure Which item is not mentioned in the SAE J1991 standard of refrigerant purity? ...

What should you do when replacing hoses? Make sure you have the correct type/size of tubing What does GWP stand for? Global Warming Potential CO2 is equal to what A/C system? R-744 HFO-1234yf systems are acceptable in what kinds of vehicles? Passenger cars, light-duty trucks, medium-duty passenger vehicles, heavy-duty pickup trucks, and complete heavy-duty vans HFO-1234yf systems are not acceptable in what kinds of vehicles? Heavy-duty trucks, refrigerated transport, and of...

Customer premises - Connected to the network through distribution taps spliced into the coaxial cable. Branches in the architecture - The downstream signal is distributed within nearby neighborhoods using 0.412-inch to 0.625-inch diameter coaxial cable, splitters, and directional couplers. Bridger amplifier - A portion of the downstream signal is boosted before being split and routed to as many as four separate coaxial cables—the branches in the architecture. Trunk amplifiers - Seve...

What are three principle characteristics that define an AC waveform? - Answer- The three principle characteristics that define an AC waveform are: (1) frequency; (2) wavelength; and (3) amplitude. What is one of the basic principles of resistance reflected in the familiar practices of grounding and bonding? - Answer- Grounding and bonding practices reflect the basic principle that electricity always follows the path of least resistance. What comprises the impedance of a coaxial cable or a ...

In the tree-and-branch architecture, how is the downstream signal from the trunk fed to the distribution branches? Within each trunk amplifier, a portion of the downstream is fed to a bridger amplifier to boost the signal before being split and routed to the distribution branches. What is a common solution when congestion from modem activity and traffic becomes unacceptable in a hybrid fiber/coax (HFC) network? Node splitting, the subdividing of serving areas into two or more smaller servin...

EPA 608 UNIVERSAL EXAM WITH 400 REAL EXAM QUESTIONS AND 100% CORRECT ANSWERS (GUARANTEED A)/ EPA 608 UNIVERSAL EXAM (NEW!!) Equipment covered by EPA regulations include: - all air-conditioning and refrigeration equipment using CFC, HCFC or HFC refrigerants. All devices used for a refrigerant recovery must: - Meet EPA standards Reusable refrigerant containers that are normally under any pressure above 15 pig must be hydrostatically tested and date stamped every: - 5 Years The EPA can ...