Like a diseased body, a defective portable power system will present symptoms. A Portal Power Distribution Technician, like a physician, must not only be able to recognize the symptoms but also have the analytic tools required to diagnose the problem and arrive at a cure. In this workshop we learn how to recognize and treat the symptoms of a resistive neutral. A resistive neutral occurs when the system neutral has a high impedance. Good electrical connections have extremely low impedance (much less than an ohm), but a resistive neutral has an intermediate impedance (more than 3 Ω). Its impedance is low enough to conduct electricity, but too high to conduct it well. A resistive neutral will cause phase voltages to float, HMI ballasts not to strike, and possibly even cause a generator to fail.

Students should bring their digital multi- and clamp meters and a WIFI-compatible laptop (cellular phones will work but not ideal).

• Example of Resistive Neutrals (Case Study)

• The Scientific Method

• Unbalanced Phase Voltages and their causes

  • Open Neutrals

  • Resistive Neutrals

• VNeg

• How to mitigate the effects of a resistive neutral

  • Load Balancing

• Sources of resistance in a system neutral

  • Loose Connections

  • Corrosion

  • Damaged Cable

    • Ways to prevent cable damage

• How to mitigate the effects of a resistive neutral (cont.)

  • Oversizing Cable

  • Paralleling Feeders

• Isolating resistance in energized systems

• Safe Metering Practices

• Isolating resistance in un-energized systems

Details

Language: English

Format: In-person, Virtual

Length: 8 hours

Trainer

Guy Holt, IATSE Local 481

Location: Boston, MA

Guy Holt is a 28-year veteran of IATSE Local 481 and author of over twenty articles for Protocol magazine on power generation, quality, and distribution in motion picture production. Guy has served as Gaffer, Rigging Gaffer, and Generator Operator on numerous film and television productions.