AmerCable, a manufacturer of electrical cables for the offshore drilling industry, has developed a 2kV rated motor lead power cable to be used in 600V high horsepower (>100hp) Variable Frequency Drive (VFD) applications. The conductor insulation is Gexol, a material known in the harsh offshore drilling industry for its superior mechanical and electrical properties. Because Gexol has an extremely low dielectric constant, the cable has a lower capacitance. This lower capacitance results in reduced common mode interference current flowing into the plant ground system.
The cable contains three symmetrical phase leads and three symmetrical ground leads. These symmetrical ground conductors reduce induced voltage imbalances and carry common mode noise back to the drive. According to the manufacturer, it reduces bearing currents at fundamental frequency. The 2kV insulation on the phase leads withstands the 3X voltage spikes normally associated with VFD applications and also reduces the drive/motor lead impedance mismatch.
The overall copper braid plus aluminum tape shield provides close to 100% coverage and a low impedance path for common mode current to return to the inverter.
Because all of the components in the cable are designed for flexibility (ie. high strand count conductors, rubber insulation and jacket materials, and a braided shield), handling and installation are facilitated. The Gexol insulation material is rated for 125„aC continuous operation ensuring a long life in high temperature environments.
AmerCable¡¦s Type VFD Gexol-insulated cables are UL Listed as Marine Shipboard Cable and Type TC. They meet the same crush and impact tests required for Type MC-HL cable. These cables are also approved by the American Bureau of Shipping, Det Norske Veritas, Lloyd¡¦s Register of Shipping, Transport Canada and are CSA Listed as Type RW90.