Supercaps in medical imaging equipment

Ziehm Imaging* uses SECH ultracapacitors in medical C-arm

Ultracapacitors play an important role in medical imaging devices such as Ziehm Imaging’s* C-arm. Schukat shows you which functions these passive components perform, and which characteristics are particularly important when using them with medical technology applications.

C-arms are medical devices used for imaging and are employed in a wide range of application areas in hospitals and medical practices, including orthopaedics, pain therapy, traumatology, heart surgery, vascular surgery, paediatrics, interventional cardiology, general and spinal surgery, neurosurgery, endoscopy, and many more.

The mobile x-ray machines from Ziehm Imaging*, thanks to SmartDose, deliver a reduced dosage of radiation without sacrificing excellent image quality or ease of use, at the same time allowing customers to individually configure the units according to their needs. Because of the high quality standards that apply in medical technology, every component has to function extremely reliably and have a long service life. When operating medical equipment of this kind, supercapacitors are indispensable

Which functions do the supercaps perform?

A C-arm operates on 230V input voltage, but especially for cardiovascular applications with long fluoroscopy times, as well as for 3D scans, high power is needed. Supercapacitors buffer this energy and make it available as needed, then recharge during operation.

To achieve this, supercap modules are used, each containing 112 cells installed in a specially designed slide-in housing. This allows the modules to be easily replaced during servicing, with the module being installed in the base of the mobile stand.

Which properties of ultracapacitors are the most crucial?

The components require a low ESR value and an enclosed design. Due to the often tight installation space, the small size and high capacity of the cells are both important. There also has to be a safety valve, to allow the condensers to degas. If the capacitors were to abruptly fail, the C-arm would only be able to deliver radiation at reduced power, although it would remain functional. This would have no negative impact on patient protection.

Which supercaps are used?

Ziehm Imaging* uses the high quality 35mm type C35S-3R0-0360 ultracapacitors from SECH in its medical equipment. These have a rated voltage of 3VDC and rated capacitance of 360F, and measure just 62.7 x 35.3mm. They deliver very high power density with extremely low ESR — less than 1.4 and 1.8 mΩ respectively — with a cycle life of around 1 million cycles and excellent DC life of 1500h (at 65°C). The cells are hermetically sealed and extremely robust thanks to their laser-welded design. They have radial terminals for PCB mounting and operate in a temperature range from -40 to +65°C.

Component selection

Medical technology demands a long lifetime, and market availability must also be guaranteed for all components in use, and Ziehm Imaging thus places particular value on the support provided by its distributor. The company has found the fast, competent support it needs in Schukat electronic, with customers benefiting from direct contact persons and speedy processing of their enquiries as well as the provision of datasheets and samples.

At Schukat

Schukat electronic offers SECH’s 35mm supercapacitors as well as many more of the manufacturer’s capacitor models direct from stock.

If you have any questions about these passive components, the distributor’s sales team are happy to advise you.

* Ziehm Imaging has specialised in the development, production and worldwide marketing of mobile C-arms for almost 50 years and has already installed more than 14,000 medical devices in over 70 countries. They have also acquired more than 10 years’ experience in flat-panel detector technology.