Variable Frequency Drive Cable VFD

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Variable Frequency Drive Cable (VFD)
Incorporated
Oil and Gas Business Unit

• Presenter
• Michael Hammons

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Variable Frequency Drives

• VFDs adjust the speed of a driven shaft to a
  predetermined speed, often this is done via an
  automatic speed selection process.
• These automatic processors often use reference
  signals generated by other devices, drives,
  controllers, limiters etc.
• VFDs can control speeds to within 0.1 tolerance
  and are the control system of choice in many
  speed control applications.

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Typical VFD Applications

• Marine propulsion, power generation, dynamic
  positioning, and work vessel systems.
• Oil Gas control systems for pumps, gas and
  diesel engines, compressors, turbines, boilers,
  conveyers.
• Environmental in waste water, potable water,
  pollution control, pumping, desalination, ozone
  regeneration.
• Industrial Paper Mills, Cement Plants, Mining
  Controls, Car Plants, Steel Mills,

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Advantages of VFDs

• Good process control, no other AC motor control
  method compares in accuracy and ease of use.
• Cost savings, by better control of motors, a
  motor run at half speed only uses 25 of the
  energy it needs at full speed.
• Smooth start and stop, single speed motors go
  from stop to full speed abruptly leading to early
  failures.
• Reduces motor over heating.
• VFDs can run special operating patterns for
  complex processes.

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Disadvantages of VFDs

• Produces noise due to PWM that can interfere
  with other susceptible circuits.
• Reflected Wave Voltages.
• EMI, both reflected and conducted.
• Noise can lead to drive over current, circuit
  malfunction, and motor bearing failures.
• Need to keep cable runs short to limit noise.

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Solutions for VFD Disadvantages
Make Special Motor Leads
Install Special Filters
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AmerCables Solution to VFD Disadvantages

• Develop a cable that reduces the amount of
  noise produced by the VFD.
• Make sure such a cable is commercially viable.
• Develop a Type VFD Cable that combines the user
  friendly features of the other Gexol Brand
  Cables.
• Type VFD exists, is installed, and recommended by
  several VFD Manufacturers.

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Type VFD Advantages

• Extremely low dielectric constant reduces cable
  capacitance, reduces CM current, reduces motor
  bearing currents.
• Lower capacitance allows for longer cable
  lengths.
• Smaller mismatch between cable and motor surge
  impedances reduces reflected wave voltages.
• Cable symmetry reduces impedance imbalances.
• 2kV insulation thickness prevents corona
  inception at 3 x voltage spikes normally seen
  from VFDs.
• Combination foil braid shield and insulated
  ground wires return reflected wave and common
  mode currents back to the drive.
• Combination shield/ground system reduces EMI,
  both conducted and radiated.
• Higher temperature rating of Type P Insulation
  withstands high heat conditions caused by high
  motor loads.

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Non-Electrical Advantages of Type VFD

• Extremely flexible, makes it easy to install.
• Small bend radius.
• UL listed as Marine Shipboard Cable, Type TC, and
  Open Wiring. ABS, DNV, and LRS Type Approved.
• Open Wiring marking allows installation of cable
  without using conduit or cable tray for the
  first/last 20m runs.
• Suitable for use in Class 1, Division 1 (if
  armored) and Class 1, Division 2 hazardous areas.
• Vibration suitability.
• Reduced installed cost.