EDS’ packaged drive solutions deliver 5- to 400-hp performance at 360-480 vac operation. When optioned, the drive panels seamlessly combine the reliability and performance of Siemens 6-Pulse G120 series drives with harmonic reduction technology, along with bypass and disconnect, in a single, compact, cost-effective and easy-to-install package. They are available as a 6-pulse harmonic reduction solution, and are specifically engineered to help meet, at the system level, IEEE 519-1992 guidelines for current distortion limits for VFD installations. They are available in heavy-duty and free-standing NEMA 1, 12, and 3R enclosures and a variety of package configurations to satisfy a wide variety of operating needs and environments. They require no additional electrical wiring or electrical devices to operate.
IEEE-519 Voltage Distortion Limits
Special applications (hospitals, airports) 3%
General systems applications 5%
Dedicated systems (100% converter load) 10%

Harmonic Mitigation
In some installations with multiple drives and small source transformers, it may be necessary to add additional Harmonic Filters to limit distortion to levels outlined in IEEE519. EDS (through Mirus SOLV Harmonic Analysis Software) can perform a computer generated harmonic analysis to determine the harmonic impact of EDS VFDs at a particular site. Mirus Lineator Advanced Universal Harmonic Filter (AUHF) can be used if required to mitigate harmonics. Mirus AUHF will reduce harmonics to meet IEEE Std 519 limits where VFD's are used for Water / Waste Water, Oil & Gas, HVAC systems, etc. Exceeds 18-pulse performance in a smaller footprint, at lower cost and without sacrificing energy efficiency.
Lineator Advanced Universal Harmonic Filter Warranty and Peformance Guarantee.
To calculate harmonics of a system, the following data must be supplied:
  • Source transformer kVA, impedance, and short circuit capacity
  • Total quantity of VFDs, HP, and voltage fed from source.
  • Total HP of other non-VFD loads (ie: full voltage starters)
  • If multiple source transformers are used to feed groups of VFDs, then a breakdown of HP groupings is required.
  • An electrical one-line diagram of distribution system.

Before adding a VFD, determine the total harmonics generating loads on the unit substation transformer. The new harmonic generating loads shall not exceed 10 percent of the transformer base rating. Harmonic generating loads, as defined here, include electronic ballasts, computers and their peripherals, solid state power supplies, UPS systems, VFD drives, etc.
If the total load on the transformer, after the additions of the current project, exceeds 75% of its rating; and/or if the total harmonic generating loads on a substation will exceed 50%; the consultant generally prepares a study for review by the client showing that the transformer can safely carry those loads. If the study shows the transformer inadequate, the project shall either increase the transformer size, or add additional transformers. Before adding a VFD, evaluate the possible effects of the VFD on power factor correcting capacitors or harmonic sensitive equipment on the same bus. Avoid installing a VFD on the same bus with capacitors or 'sensitive' equipment. Sensitive equipment, as defined here, are loads adversely affected by harmonic voltage distortions. These include high sensitivity laboratory equipment, patient monitoring or treatment equipment, computers, etc. Provide calculations per IEEE Standard 519 showing the current and voltage total harmonic distortion (THD) that will be reflected into the existing client power system, for any load exceeding 10% of the rating of the transformer serving it. The VFD shall limit the THD to the values noted below when operating at any load from zero to 100 percent.
  • VFD input voltage waveform: less than 3 percent THD
  • VFD input current waveform: less than 100 percent THD

After startup of the VFD, the mechanical contractor generally provides, and the electrical contractor installs, any additional reactors or filters required to reduce the actual THD to the calculated THD.
The Inversine Advanced Universal Sine-wave Filter (AUSF) is designed to address the problems resulting from pulse width modulation. It is a low pass filter with cutoff frequency well below the switching frequency of the inverter.

The AUSF is much more than a simple dV/dT filter and will:
  • substantially reduce voltage rise time (dV/dt)
  • convert output voltage to near sinusoidal waveform (<3%)
  • prevent transient overvoltages at motor terminals
  • lower harmonic losses in the motor
  • reduce motor noise
  • reduce motor and cable insulation stress
  • extend life of the motor and ASD
  • When Motor does not have adequate insulation for ASD duty
  • Using a number of parallel motors
  • Long Motor cable length
  • When Step-up/Step-down transformer is used between ASD and motor
  • There are specific requirements for peak voltage level and dV/dt rise time
  • Motor noise needs to be reduced
  • Maximum safety and reliability is needed in hazardous environments
  • Submersible pumps with long motor cables used in the oil & gas industry