Safe power for medical devices used at home: Page 2 of 3

February 13, 2015 //By Herbert Blum
Safe power for medical devices used at home
An aging population and the rising cost of healthcare around the world are a matter of concern to the general public these days. This is especially true in the USA, where keeping costs under control becomes more and more challenging.
This ensures that the two conductors, consisting of the phase and neutral conductor, are sufficiently insulated against all other surfaces that can be touched. If the surfaces that can be touched are electrically conductive, the gaps and insulations also have to be doubled. The clearance and creepage gaps for Protection Class I are 4 mm between live conductors and metal enclosures or ground conductors. This value is doubled in Protection Class II, corresponding to a gap of 8 mm between live conductors and a metal enclosure.

5008: C8 appliance inlet with filter

A C8 style IEC connector with a maximum rated current of 2.5 A is suitable for all devices with outputs up to approx 500 W. Matching connecting cables are available with 2-pin Euro and National Electrical Manufacturing Association (NEMA) plugs.

The C18 connector, with a rated current up to 10A VDE and 15 A UL is available for medical devices with higher outputs.

 C18 PEM connector 5707 with V-Lock locking system and IP 65 protection

Complying with EMC for domestic medical equipment

Since laypersons operate medical devices at home, special attention to the equipment's ability to effectively suppress interference is needed. This also includes ensuring electromagnetic compatibility (EMC). Most devices today are supplied with power by switched-mode power supplies. These are suitable for the various mains voltages around the world and have a high efficiency, due to the fast switching capability by ICs.

These switching ICs, however, cause great interferences that can be measured on the power mains. The EMC standards specify limits for conducted and radiated interfering voltages. This is a precondition for compliance with the EMC standards, which in turn is necessary for the CE conformity marking. The use of a filter is recommended because of the interferences caused by modern electronic devices. A filter can be discreetly mounted on the PC board or used as a block or in line filter in combination with the connector. 

Design category: 

Vous êtes certain ?

Si vous désactivez les cookies, vous ne pouvez plus naviguer sur le site.

Vous allez être rediriger vers Google.