Abb Research Ltd.

Ralf Str&uuml;mpler

Joachim Glatz-Reichenbach

Felix Greuter

Erkki Rajala

Timo Jokiniemi

Uwe Kaltenborn

Petra Kluge-Weiss

Jorgen Skindhoj

Ruzica Loitzl-Jelenic

J&ouml;rgen Skindhoj

A microswitch produced from a predominantly plate-shaped substrate can include: a stationary contact piece ( ) on the substrate, a moveable contact piece ( ), which electrical contacts the stationary contact piece ( ) in the switch-on position of the switch and is electrically isolated from the stationary contact piece in the switch-off position of the switch, a bendable contact carrier ( ) which holds the moveable contact piece ( ) and is fixed to the substrate by two ends ( ), and a drive ( ) which guides the contact carrier ( ) into the switch-on or switch-off position by elastic deformation. The contact carrier ( ) can deform in substrate-parallel fashion. In a stable position corresponding to the switch-off position, the contact carrier ( ) has the form of a symmetrical antinode. In a stable position corresponding to the switch-on position, the contact carrier ( ) is deformed in the manner of an asymmetrical antinode.

Microswitch

The invention relates to a combination of a microrelay switch ( ) switching off small overcurrents, and a short-circuit current limiter, for example a fuse link, a PTC thermistor or a power breaker, for limiting or switching of large overcurrents.

Electrical circuit breaker for protecting against overcurrents

The invention relates to an apparatus for limiting an electrical current by using a PTC resistor being monitored by a monitor circuit. According to the invention, the monitor circuit issues a signal only after detecting the status of the PTC resistor for a defined time period after a PTC resistance change.

Apparatus for limiting an electrical current

The invention relates to a novel micro relay for switching electric currents, in which a movable contact piece moves parallel to the substrate.

Microrelay working parallel to the substrate

A fuse has a fuse element ( ), composed of silver, with constrictions ( ) which follow one another at regular intervals, and which fuse element makes contact with a combustible element ( ), preferably over its entire length. The combustible element ( ) is composed of a combustion compound, which is essentially of a fuel such as guanidine or a guanidine derivative and a metal such as Mg or Al and an oxidant such as KNO , NaNO , NH NO , KClO , NaClO , KMnO , the proportion of which is overstoichiometric by a factor of at least 1.1, and preferably of at least 10. The combustible compound also preferably contains a binding agent such as paraffin, a thermoplastic or an elastomer, so that it can be extruded. It has an ignition temperature of between 160&deg; C. and 260&deg; C. and emits more than 200 J/g of heat, so that it ignites even in the event of small overcurrents and melts the entire length of the fuse element ( ).

Fuse with overstoichiometric amount of oxidant

An electrical monitor circuit in which star points of taps on a first and a second side of a three-phase current limiting device are voltage compared. Possible applications are combinations with electrical switches, especially for power supplying and protecting circuits for electrical motors.

Monitor circuit for a current limiting device

Non-linear resistance with varistor behavior and method for the production thereof

The invention relates to an electric device with a PTC polymer element having a constriction. The constriction defines a web extending in a main current direction over a length longer than in the prior art, namely longer than 5 mm, preferably longer than 15 mm. Further, the aperture angle of the PTC polymer material at the ends of the web is larger than 100&deg;. A preferred choice of material is given, further. The invention achieves very high voltage-withstand capabilities.

Electrical device comprising a PTC polymer element for overcurrent fault and short-circuit fault protection

A protective element for protecting in particular an electric motor against overload currents includes in a polymer matrix, preferably ETFE, for example 40% (by volume) of a first powdered filler of a conductive material, preferably TiB , so that, as in the case of a PTC element, the resistance increases abruptly at a switching temperature corresponding to the melting temperature of the polymer. Also added are 20% (by volume) of a second powdered filler, a phase transition material which, at a critical temperature below the switching temperature, undergoes a phase transition in which it absorbs heat of transformation. As a result, the response time (T) of the protective element is notably extended in a range of the overload current factor (F) corresponding to higher permissible motor starting currents. Examples of materials which come into consideration for the second filler are those with a solid-solid phase transition such as pentaerythritol, NaNO , NaNO or else with a solid-liquid phase transition such as UHMWPE, quinol or, in particular, microencapsulated metals, alloys and salts.

Protective element

A description is given of a PTC polymer element (,) as part of an electrical component with a novel structure in which aperture angles (&agr;) on both sides of constrictions (,) in the PTC polymer material are at least 100&deg;. As a result, an improved response behavior can be achieved, and, in connection with further features, the construction of PTC polymer elements which are more rapid, capable of carrying greater currents and have higher dielectric strengths is possible.

Growing community of inventors

Gebenstorf, Switzerland

Ralf Strümpler

Growing community of inventors

Gebenstorf, Switzerland

Ralf Str&uuml;mpler

Ralf Strümpler