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CAGE Code: 5DME2
ITAR Registration Code: M28889

- January 22nd 2020 -
Call: 1 (800) 377-3244
We Are Open Monday-Friday 8 am - 5 pm PT

High Current Encapsulated Inductors:
EES and EEK Series. Potted.

The CWS' EES and EEK Series of High Power Inductor and High Current Inductor are designed using Helical Winding (Helix Coil) in semi quasi planar structure to achieve lower DC resistance (DCR), lower AC resistance (skin effect loss), and high inductance. The core materials used are Distributed Air Gaps Compacted Cores from Magnetics, CSC and Micrometal. Both Gapped and UnGapped cores are used to extend the DC bias capability.

LT SPICE model can be downloaded from the link LT Spice for E Series, LT SPICE for E Series,.

Thermal model can be downloaded from the link provided in the table below for each part # .

Power Loss Calculator can be used from the link provided in the table below for each part # .

Power Loss Calculator Help/Guide/Example file can be downloaded here, Power Loss Calc Help/Guide/Example file.

These are potted inductors. For unpotted versions, please see our ES, EK, and E73040-Series.

The table below shows the types of cores used in each of the part numbers. The EES Series are using Sendust or KoolMu core type and is suitable for swinging chokes, energy storage filter inductor in SMPS with high ripple current, in-line noise filters with large AC voltage swing, unidirectional drive application such as pulse transformer and flyback transformer. Sendust or KoolMu has good frequency response up to 1 Mhz, lower core losses, and will operate at a lower temperature.

The EEK Series are for those applications requiring small inductance drop when a high DC current (DC bias) is flowing into the inductor. The EEK series are built using Mega Flux cores with higher saturation flux density. The EEK Mega Flux version is suitable for Output Ripple filtering, High Power Output Chokes and High Current Inductor where good DC bias characteristics are desired. The core loss of the Sendust/Koolmu and Mega Flux are very similar at a frequency below 300 Khz. Mega Flux version cost a little more than the others. Mega Flux cores are not suitable for application over 750 Khz, and has a much higher core loss than the Koolmu/Sendust cores.

The part PDF drawing has the DC Bias Current versus Inductance table. It is not necessary that Inductors with higher Inductance versus DC Bias Current is better in all cases. This is because Energy Storage in a filter is defined as 1/2 x [L] x [Sq I], where [L] is the inductance and [Sq I] is the square of the current flowing into the Inductor. For energy storage filtering applications, having a good DC bias is not always a desired feature. When the current flow into the inductor increases, the amount of energy stored increased to the square of the current [Sq I], and if the inductance [L] does not drop when the current increase, the energy stored maybe too high and could potentially cause a circuit to blow up. For such energy storage filtering application such as Input Filter ( Phi or butterworth or chebyshev filters), or the Boost Inductor, the EES Series using Koolmu or Sendust is usually the desired choice. However, every application is different and the design engineer must balance the trade-offs.

Industrial High Current Filter Inductors, Switching Regulator Inductor, In-Line Noise Filters, Differential Mode Choke, Boost Power Factor Correction Choke and Welding Machine Output Inductor.
Inductance range from 10 uH to 200 uH, Current Rating from 10 Amps to 250 Amps.
Designed with High Flux, Kool Mu, Sendust or Iron Powder E-Cores.
Custom design available. Please email or call us.

  • Can achieve up to 60% more energy storage than wire wound Inductors
  • Use of Flat Helical winding to reduce DCR, lower copper loss, reduce size, even out heat dissipation and achieve up to 80% of copper fill factor
  • Helix coils are self supported with no bobbins or coil forms
  • Designed using High Flux, MFlux, KoolMu Sendust cores for extreme high temperature operations of 200 deg C
  • Designed using gapped and un-gapped Micrometal's 40, 52 and 8/90 mix Iron Powder Cores for high saturation flux and lower cost.
  • Designed for commercial, industrial and military application
  • Operating temperature range: -55 deg C to +200 deg C
  • Inductance values : 1 uH to 80 uH
  • Current rating : Up to 250 Amps
  • Low Cost mass producible design
  • Background on Helical Winding Output Inductors.

1)The prices shown below are for sample or prototyping low quantity. Please call
800-377-3244 or
email for larger volume OEM pricing.
2) Our large OEM pricing is extremely competitive. We will meet or beat any competitors prices with better deliveries
3) Custom designs are available to meet any of your requirements. Please contact us
) The data shown below can be sorted by clicking each column header.Click once again to sort in reverse order.
5) Rated Current is based on a 60 deg C temperature rise at an ambient temperature of 40 deg C. High Flux, KoolMu, Sendust versions can operate to over 200 deg C. Iron Powder cores may exhibit thermal aging which limits the operating temperature to 100 deg C.
6) Helical wire used on High Flux, KoolMu, Sendust and Iron Powder versions has Kapton insulation and can withstand a temperature of 220 deg C.

  Part Number Inductance Current
Rating (Amps)
at 25 Amps
DC Bias
DCR Max (milli-Ohms) L (uH)
@ DC Bias (Amps)
Core Material SolidWorks Model Thermal Model Power Loss LT Spice Price  
  EEK55246-341M-40A 340.00 uH 40 254.0 uH 14.50 162.0 uH @40A Powder Core SolidWorks Model Thermal Model Power Loss LT SPICE $95.00
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  EES55246-341M-27A 340.00 uH 27 129.0 uH 13.50 120.0 uH @27A Powder Core         $95.00
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  EEK55246-221M-50A 220.00 uH 50 182.0 uH 10.00 112.0 uH @50A Powder Core     Power Loss LT SPICE $95.00
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  EES55246-171M-40A 170.00 uH 40 96.0 uH 6.90 73.0 uH @40A Powder Core         $95.00
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  EEK55246-171M-60A 170.00 uH 60 142.0 uH 7.00 83.0 uH @60A Powder Core SolidWorks Model Thermal Model Power Loss LT SPICE $95.00
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  EES55246-341M-40A 170.00 uH 40 180.0 uH 6.90 130.0 uH @40A Powder Core SolidWorks Model Thermal Model Power Loss LT SPICE
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  EES55244-131M-45A 130.00 uH 45 87.0 uH 6.60 70.0 uH @45A Powder Core         $95.00
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  EE70340-413 115.00 uH 90 81.00 8.5 53uH @50A Powder Core         $200.00
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  EE70340-413X 115.00 uH 90 81.00 10 53uH @50A Powder Core         $200.00
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  EES55246-111M-60A 110.00 uH 60 67.0 uH 4.00 43.0 uH @60A Powder Core         $95.00
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  EE70340-313 85.00 uH 90 61.0 uH 6.50 40uH @50A Powder Core         $150.00
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  EE70340-313X 85.00 uH 90 61.0 uH 8.00 40uH @50A Powder Core         $150.00
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  EEK55246-800M-85A 80.00 uH 85 80.0 uH 3.00 43.0 uH @85A Powder Core SolidWorks Model Thermal Model Power Loss LT SPICE $95.00
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  EES55206-800M-75A 80.00 uH 75 59.0 uH 3.00 29.0 uH @75A Powder Core SolidWorks Model Thermal Model Power Loss LT SPICE $95.00
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  SEK55246-800M-85A 80.00 uH 85 85uH 3.00 43.0 uH @85A Powder Core SolidWorks Model Thermal Model Power Loss LT SPICE
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  EES55244-600M-90A 60.00 uH 90 50.0 uH 3.00 19.0 uH @90A Powder Core         $95.00
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  EE70340-213 57.00 uH 120 40.0 uH 5.00 27uH @50A Powder Core         $100.00
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  EE70340-213X 55.00 uH 120 40.0 uH 7.00 27uH @50A Powder Core         $100.00
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  EES55246-300M-180A 30.00 uH 180 23.3 uH 1.00 10.2 uH @180A Powder Core SolidWorks Model Thermal Model Power Loss LT SPICE $95.00
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  EE70340-113 30.00 uH 90 20.5 uH 2.50 14uH @50A Powder Core         $50.00
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  EE70340-113X 30.00 uH 90 20.5 uH 3.00 14uH @50A Powder Core         $50.00
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  EES55244-210M-180A 21.00 uH 180 19.3 uH 1.00 6.5 uH @180A Powder Core         $95.00
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  EES55204-200M-160A 20.00 uH 160 16.7 uH 1.00 8.4 uH @160A Powder Core         $95.00
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  EES55242-140M-200A 14.00 uH 200 13.7 uH 1.10 9.9 uH @200A Powder Core         $95.00
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  EES55202-140M-160A 14.00 uH 160 13.2 uH 0.98 8.4 uH @160A Powder Core         $95.00
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Disclaimer: Coil Winding Specialist, Inc., its affiliates, agents, and employees acting on behalf of Coil Winding Specialist, Inc. (collectively, CWS) disclaim any and all liability for any errors, inaccuracies or incompleteness contained herein or in any other disclosure relating to any product. CWS reserves the right at any time and from time to time to make changes to design, technical specification, or construction of any product listed on this website without notice. CWS also reserves the right to discontinue or limit sale of any product or service available throughout this website on temporary or permanently basis without notice. CWS highly recommends customers not to use its products offered on this website for inappropriate use and applications. Products should be tested for its suitability by prospective customers in all possible applications and conditions. Customers using or selling CWS products for use in other than recommended applications do so entirely at their own risk and agree to fully indemnify CWS from any damages arising or resulting from such use or sale.

WARNING: This product can expose you to chemicals which is [are] known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go

Any Comments, Suggestions or Questions? Contact us! Email:
CWS 353 West Grove Ave. Orange, California 92865
Call us Toll Free: 1-800-679-3184 or 1 (800) 377-3244

Tel: (714) 279-9010, Fax: (714) 279-9482

Copyright 2008, Coil Winding Specialist, Inc
Updated July, 2013

CAGE Code: 5DME2(Registered with