Ohtama Co., LTD. – Specializing in permalloy, magnetic shielding, magnetic field measurement, heat treatment and magnetic field cancellation.


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Ohtama are professionals in the area of magnetic shielding and magnetic collection components and manufacture a range of products using a variety of materials with a strong focus on iron-nickel alloys (Permalloy).

Sensor cores & yokes

Sensor cores and yoke

Various permaloy cores for current sensors (clamp cores) and CT (current transformer) cores are available.

Magnetic shield rooms & cases

Magnetically Shielded Room & cases

Ohtama offers a range of solutions to shield against external magnetic fields and to prevent the leakage of generated magnetic fields.

Magnetic shielding components

Magnetic shielding components

Shielding components for telecommunications equipment, broadcasting equipment, electron beams and electron microscopes used in semiconductor applications and medical equipment etc.


Magnetic annealing & heat treatment

Ohtama offers a range of heat treatment services, including magnetic annealing of Permalloy and pure iron materials in a hydrogen atmosphere or in a vacuum.


Sales of materials

We keep an extensive inventory of permalloy materials, PC or PB, according to the customer’s request.

Magnetic field measurement services

Magnetic field measurement services

Ohtama provides onsite measurements at facilities where electron beam applications are used and a range of other low-frequency magnetic field measurements.

Magnetic annealing & heat treatment

Magnetic field measurement & analysis

Magnetic field analysis and a variety of design services are also pne of Ohtam's best solution at your service. 

Active magnetic shields (magnetic field cancellers)

Ohtama offers active magnetic shield system using  using high sensitive sensors and a Helmholtz coil

Magnetic field measurement & analysis

Next-generation magnetic shielding materials

Watch this space! We are currently in the process of developing new, light-weight, ultra-high-performance magnetic shields under contract of the Ministry of Economy, Trade and Industry of Japan.

e-MotorChamber image


This is a ground-breaking EMC assessment system for EV motors, whose demand is increasing due to the shift to electric vehicles (EV) and hybrid vehicles (HV) in the automobile market. From EMC testing in the demonstration anechoic chamber to customized sales of the system, the Ohtama Group is here and ready to provide you with its full support.


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