Class 8839 Econoflex™ AC Drives
Application Information
204 09/2003
© 2000–2003 Schneider Electric All Rights Reserved
APPLICATION INFORMATION (CONTINUED)
Harmonics
Any device that uses a switching power device will produce a non-linear load and harmonics. The
suggested guidelines for voltage and current distortion are addressed in IEEE Standard 519 -1992 titled
“IEEE Recommended Practices and Requirements for Harmonic Control in Electrical Power Systems.”
IEEE 519-1992 suggests distortion limits dependent upon the electric power distribution system for
industrial and commercial consumers.
Collectively, all factory loads and the building electrical distribution network determines the harmonic
levels at the user and electric utility interface. Commonly misapplied, the Electrical Power Research
Institute (EPRI) recognizes the interface between user and electric ut ility (energ y meter) in the electrical
distribution network. This position is also supported in the Application Guide (P519A) prepared by the
Harmonics Working Group of IEEE. Square D Company will typically provide line reactors or drive
isolation transformers as the most cost effective method of harmonic abatement.
There are alternative methods of harmonic abatement that can be supplied such as 18 pulse and Mirus
Lineator™ suppressors, not included within this catalog.
Input Current Ratings
Square D publishes input currents based on distribution system impedance at various available fault
current ratings. Our literature reflects multiple input current ratings based on available fault currents.
• 5,000 AIC (1 to 50 HP @ 208/230/460 V)
• 10,000 AIC (60 to 100 HP @ 460 V)
• 22,000 AIC (1 to 100 HP @ 460 V and 1 to 50 HP @ 208/230 V when Mod G09 is selected)
Line reactors are provided with the majority of AC drives today. Line reactors are included in the
Econoflex for 25 to 100 HP at 460 Vac and 15 to 50 HP at 208/230 Vac. Select Mod A09 to include a
factory-enclosed reactor for 1 to 20 HP at 460 Vac and 1 to 10 HP at 208/230 V.
The use of line reactance ahead of the AC drive will:
• Reduce line current harmonic injection into the primary source.
• Limit the total harmonic voltage distortion from the AC drive at the pint of common coupling to align
with IEEE 519.
• Lower the available feeder short circuit capacity.
• Meet specified line impedance requirements.
• Prevent AC drive nuisance tripping due to transient overvoltages from power factor correction
capacitor switching.
• All branch circuit components and equipment must be rated for the inpu t current of the drive co ntroller
or the rated output current whichever value is larger.
Drive Isolation Transformer
Square D does not suggest the use of a drive isolation transformer unless the system requires one or
more of items listed below. In addition to the functional comparison of a line reactor, drive transformers
are normally used for one of the following reasons:
• Match system voltage to drive rating.
• Meet local or plant codes that require isolation.
• Capable of correcting line voltage unbalance c on ditions commonly seen with open delta and corner
grounded delta distribution systems.
• Provides continuity of service for nuisance grounding.
• Reduces drive induced current in supply feeder ground and limit ground fault currents.
• Isolate the electrical common mode noise generated in solid state controllers from the distribution
system.