Small Wind Installer Flashcards

Per NEC Article 694, what type of disconnecting means is required for utility-interactive small wind systems?

Answer: An accessible, load-break rated disconnecting means that utility personnel can operate

NEC 694.22 requires an accessible, load-break rated disconnecting means so that utility personnel can safely de-energize the wind system from the utility side.

For a small wind system installed on a one- or two-family dwelling, what is the maximum system voltage permitted under NEC Article 694?

Answer: 600 volts

NEC Article 694.7 limits small wind system voltage to 600V for one- and two-family dwelling units, consistent with similar voltage limits in other residential renewable energy articles.

What grounding requirement applies to metal towers used for small wind turbines?

Answer: Towers must be connected to the system equipment grounding conductor

Metal towers must be bonded to the equipment grounding system so that a fault will trip overcurrent protection rather than energize the tower structure.

Before performing maintenance on a small wind turbine at the top of a tower, what is the FIRST required safety action?

Answer: Perform lockout/tagout to isolate and de-energize the turbine electrical system

Lockout/tagout must be performed first to eliminate the electrical hazard before any other maintenance steps, including climbing, are undertaken.

What document does a utility typically require before allowing a customer-owned small wind system to connect to the grid?

Answer: An executed interconnection agreement

An interconnection agreement is a formal contract with the utility that establishes the technical and legal requirements for connecting a private generation system to the grid.

A small wind turbine produces three-phase AC output at variable frequency. What conversion process makes this output compatible with the utility grid?

Answer: The variable AC is rectified to DC, then inverted to 60 Hz AC by a grid-tie inverter

Variable-frequency AC from the turbine is first converted to DC by a rectifier, then the DC is converted to stable 60 Hz AC by a grid-tie inverter for utility connection.

Which of the following best defines 'capacity factor' as applied to a small wind turbine?

Answer: The ratio of actual annual energy produced to the theoretical maximum energy if the turbine operated at rated power continuously

Capacity factor compares actual annual energy output to what the turbine would produce if it ran at full rated power every hour of the year; small wind turbines typically achieve 20–35%.