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CAGE Code: 5DME2
ITAR Registration Code: M28889

- August 19th 2018 -
Call: 1 (800) 377-3244
We Are Open Monday-Friday 8 am - 5 pm PT

High Power Inductor E Series. Unpotted.

The CWS' ES, EK and E73040 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.

These are unpotted inductors. For potted/encupsulated versions, please see our EES- and EEK-Series.

The E Series High Power Inductor and High Current Inductors are capable of handling high DC bias current, high energy storage and high voltage swing due to higher mass and higher saturation flux densities of the cores used. Various Mounting configuration with pre-tinned leads for direct connection. Mounting Spacers ( PN: EKES-SP001) can be bonded or placed under the cores to rest the inductor flat into the PCB during manufacturing, if needed.

The table below shows the types of cores used in each of the part number. The ES Series and the E70340 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. The E70340-0013 and E70340-004 are using Gapped iron powder core and and used in similar application where lower cost is needed. Sendust or KoolMu has good frequency response up to 1 Mhz, lower core losses, and will operate at a lower temperature.

The EK Series are for those application requiring small inductance drop when a high DC current (DC bias) is flowing into the inductor. The EK series are built using Mega Flux cores with higher saturation flux density. The EK Mega Flux version is suitable for Output Ripple filtering, High Power Output Chokes and High Current Inductor where a good DC bias characteristics is desired. The core loss of the Sendust/Koolmu and Mega Flux are very similiar at 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 application, 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 ES 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, Pulse Transformer, Fly Back Transformer, 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 tempertaure 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)
@ 25 Amps
DC Bias
DCR Max (milli-Ohms) Dimension:
Length x Width x Height
Core Material L (uH)
@ DC Bias (Amps)
SolidWorks Model Thermal Model Price  
  E70340-013 30.00 uH 120 Amps 23.0 uH 2.00 milli Ohms 39.0 x 39.0 x 29.0 Iron Powder 15.0 uH @50A     $36.75
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  E70340-013 Rev. C2 30.00 uH 120 Amps 23.0 uH 2.00 milli-Ohms 39.0 x 39.0 x 29.0 Iron Powder 15.0 uH @50A    
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  E70340-004 20.00 uH 120 Amps 16.0 uH 2.50 milli Ohms 43.7 x 43.7 x 33.0 Iron Powder 15.0 uH @50A     $47.30
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  E70340-015 150.00 uH 30 Amps 65.0 uH 12.00 milli Ohms 44.5 x 44.5 x 28.4 Sendust 53.0 uH @30A     $32.62
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  E70340-014 25.00 uH 150 Amps 20.0 uH 2.00 milli Ohms 44.5 x 44.5 x 29.5 Sendust 13.5 uH @50A     $37.02
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  E70340-010 12.00 uH 180 Amps 10.0 uH 0.75 milli Ohms 44.5 x 44.5 x 30.0 Sendust 7.5 uH @50A     $44.22
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  E70340-016 100.00 uH 30 Amps 70.0 uH 13.00 milli Ohms 45.0 x 46.0 x 28.4 Sendust 62.0 uH @30A     $32.62
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  EKES-SP001 0.00 N/A Spacer For Mounting 56.5 x 9.79 x 5.85 FR4 N/A     $5.00
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  CWS-1HW-12203 90.00 uH 75 Amps 69.0 uH 5.00 milli Ohms 57.0 x 45.0 x 57.0 Powdered 30.0 uH@75A    
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  CWS-11189 375.00 uH 25 Amps 190.0 uH 25.00 milli Ohms 57.0 x 45.0 x 57.0 Compacte 190.0 uH    
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  ES55206-280M-160AH 28.00 uH 160 Amps 22.0 uH 0.98 milli Ohms 57.0 x 57.0 x 35.0 Sendust 12.3 uH @100A     $53.54
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  ES55246-300M-180AH 30.00 uH 180 Amps 24.0 uH 1.00 milli Ohms 57.0 x 57.0 x 35.0 Sendust 13.4 uH @100A     $53.54
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  ES55202-140M-160AH 14.00 uH 160 Amps 13.0 uH 0.98 milli Ohms 57.0 x 57.0 x 36.0 Sendust 10.5 uH @100A     $53.50
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  ES55242-140M-200AH 14.00 uH 200 Amps 13.7 uH 1.10 milli Ohms 57.0 x 57.0 x 38.0 Sendust 9.9 uH @200A     $53.54
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  ES55204-200M-160AH 20.00 uH 160 Amps 16.0 uH 1.00 milli Ohms 57.0 x 58.0 x 36.0 Sendust 10.6 uH @100A     $53.50
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  ES55246-221M-40AH 220.00 uH 40 Amps 104.6 uH 9.70 milli Ohms 58.0 x 58.0 x 34.0 Sendust 104.6 uH @25A     $46.28
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  EK55246-221M-50AH 220.00 uH 50 Amps 182.0 uH 10.00 milli Ohms 58.0 x 58.0 x 34.0 Mega Flux 112.0 uH @50A SolidWorks Model Thermal Model $51.10
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  ES55246-341M-27AH 340.00 uH 27 Amps 129.1 uH 13.50 milli Ohms 58.0 x 58.0 x 35.0 Sendust 120.0 uH @27A     $48.68
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  EK55246-341M-40AH 340.00 uH 40 Amps 253.6 uH 13.40 milli Ohms 58.0 x 58.0 x 35.0 Mega Flux 162.0 uH @40A SolidWorks Model Thermal Model $53.50
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  ES55244-210M-180AH 21.00 uH 180 Amps 18.0 uH 0.93 milli Ohms 58.0 x 58.0 x 36.0 Sendust 12.0 uH @100A     $53.54
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  ES55244-600M-90AH 60.00 uH 90 Amps 49.0 uH 3.00 milli Ohms 58.0 x 58.0 x 36.0 Sendust 38.0 uH @50A SolidWorks Model Thermal Model $44.68
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  ES55206-800M-75AH 80.00 uH 75 Amps 59.0 uH 3.00 milli Ohms 58.0 x 58.0 x 36.0 Sendust 38.0 uH @55A     $65.00
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  ES55244-131M-45AH 130.00 uH 45 Amps 87.0 uH 6.60 milli Ohms 58.0 x 58.0 x 36.0 Sendust 73.0 uH @40A     $55.08
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  ES55246-111M-60AH 110.00 uH 60 Amps 67.0 uH 3.50 milli Ohms 58.0 x 58.0 x 36.0 Sendust 46.0 uH @50A     $66.12
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  ES55246-171M-40AH 170.00 uH 40 Amps 96.0 uH 6.90 milli Ohms 58.0 x 58.0 x 36.0 Sendust 88.0 uH @35A     $56.78
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  EK55246-171M-60AH 170.00 uH 60 Amps 142.1 uH 7.00 milli Ohms 58.0 x 58.0 x 36.0 Mega Flux 83.0 uH @60A SolidWorks Model Thermal Model $73.60
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  EK55246-800M-85AH 80.00 uH 85 Amps 79.6 uH 3.00 milli Ohms 58.0 x 58.0 x 36.0 Mega Flux 43.0 uH @85A SolidWorks Model Thermal Model $49.50
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  ES55246-161M-40AH 160.00 uH 40 Amps 133.0 uH 15.0 milli Ohms 58.0 x 58.0 x 36.0 Powdered 100 uH @40A    
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  EK55246-260M-160AH 26.00 uH 160 Amps 28.0 uH 1.10 milli Ohms 58.0 x 58.0 x 37.0 Mega Flux 24.0 uH @50A SolidWorks Model Thermal Model $53.54
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  ES55242-140M-200AV 14.00 uH 200 Amps 13.7 uH 0.96 milli Ohms 58.0 x 58.0 x 42.0 Sendust 9.9 uH @200A     $55.08
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  EF552821-131M-40AH 130.00 uH 40 Amps 126.0 uH 15.0 milli Ohms 67.0 x 72.0 x 40.0 Powdered 50.0 uH @40A    
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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

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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