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HSD 5% Passive Harmonic Filter

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TMS & TCI for over 16 years the difference in service and power quality solutions for the canadian market.


HSD 5% Passive Harmonic Filter

The HarmonicShield offers industry leading 5% iTHD performance even at light loads and under the harshest of conditions. The optional contactor allows the tuning circuit to be disconnected at light loads to avoid leading power factor problems. Natural convection cooling means no moving parts. A lug kit option accommodates oversized cabling if needed. All of this is backed up by TCI’s 3 year warranty, which means you will have many years of hassle free operation.

Why Do I Need a HarmonicShield Filter?

Harmonics are produced on an electric power system as a result of non-linear loads such as motors, pumps, power supply units, and variable frequency drives. When present in the voltage and current of an electric power system, harmonics are considered undesirable distortion which can adversely affect power system infrastructure and loads.

Issues Caused by Harmonics

  • Transformer and distribution equipment overheating
  • Random breaker tripping
  • Sensitive equipment failure
  • Poor power factor

Benefits of Using a HarmonicShield Filter

  • Cost effective, simplified design
  • Limits current harmonic distortion to less than 5% over a wide load range
  • Industry leading performance
  • IEEE 519-2014 compliant
  • Increases drive uptime
  • Eliminates nuisance tripping of circuit breakers

Quality Components

  • Optional Contactor
  • Optional Lugs
  • UL Type 1 or Type 3R Transformer Style Enclosure
  • RoHS / RoHS II compliant

SCCR Marking

Note: The HarmonicShield filter is UL Listed as an Auxiliary Device in accordance with PART X of UL 508 Standard for Industrial Control Equipment and does not require a SCCR or marking. HSD is not an Industrial Control Panel and so does not require a Short Circuit Current Rating such as is required of Industrial Control Panels to be in compliance with NFPA NEC Article 409. For applications requiring a SCCR, TMS offers the HGP product which features the same performance as the HSD and is an Industrial Control Panel with a true SCCR rating of 100ka.


Before HSDAfter HSD


The HSD not only limits current distortion to less than 5% TDD, it also improves true power factor.

Performance Guarantee

Select & install the appropriate HarmonicShield® Harmonic Filter in a variable torque, variable frequency AC drive application, within our published technical specifications and we guarantee that the input current distortion will be less than or equal to 5% THID for standard HSD Series filters at full load, and less than 8% at 30% load.  If a properly sized and installed filter fails to meet its specified THID level, TCI will provide material for necessary modifications or replacement filter at no charge.

HSD filters can also provide similar performance in other drive applications such as constant torque, DC drives and other phase controlled rectifiers, but actual THID levels can vary by load and/or speed and therefore cannot be guaranteed.

Consult TMS for assistance when applying HSD filters on these types of equipment.


The guaranteed performance levels of this filter will be achieved when the following system conditions are met:

Frequency: 60Hz ± 0.75Hz
System Voltage:
 Nominal System Voltage (line to line) ±10%, No more than 1.5% Source inductance
Balanced Line Voltage: 
Within 0.5%
Background Voltage Distortion: 
< 0.5% THVD

The input VFD current waveform shall be consistent with that of a VFD with 3% AC line reactance at full load.

NOTE: The presence of background voltage distortion will cause motors & other linear loads to draw harmonic currents. Additional harmonic currents may flow into the HGP filter if there is harmonic voltage distortion already on the system.

IEEE Standard 519-2014

Table 2 - Current distortion limits for systems rated 120 V through 69 kV

Maximum harmonic current distortion in percent of IL
Individual harmonic order (odd harmonics) a, b
ISC/IL 3≤h<11 11≤h<17 17≤h<23 23≤h<35 35≤h≤50 TDD
<20c 4.0 2.0 1.5 0.6 0.3 5.0
 20<50 7.0 3.5 2.5 1.0 0.5 8.0
 50<100 10.0 4.5 4.0 1.5 0.7 12.0
 100<1000 12.0 5.5 5.0 2.0 1.0 15.0
 >1000 15.0 7.0 6.0 2.5 1.4 20.0

Even harmonics are limited to 25% of the odd harmonic limits above.

Current distortions that result in a dc offset, e.g., half-wave converters, are not allowed.

All power generation equipment is limited to these values of current distortion, regardless of actual ISC/IL.


ISC = maximum short-circuit current at PCC

IL = maximum demand load current (fundamental frequency component) at the PCC under normal load operating conditions.

Low Capacitance HarmonicGuard Filter 

TMS now provides a low capacitance version of our HGP product. The HarmonicGuard Low Capacitance filter has been designed with roughly half the capacitance of the HGP, but provides all the same options of the HarmonicGuard Passive filter.

Specification sheets

HSD Resources + Manual :
Dimensions & Ratings :
Saturday, July 20, 2024