Electromagnetic relay wherein response voltage is rendered temperature independent
AssigneeSiemens Aktiengesellschaft
InventorRolf-Dieter Kimpel
Life of this patent
Estimating the term…
Abstract
A relay includes a permanent magnet for an armature restoring force having a highly negative temperature coefficient of remanence, where a portion of the permanent magnetic force is compensated by a compensation spring. The response voltage is rendered temperature independent by a heating means connected in parallel to the excitation winding to heat the permanent magnet in synchronization with the winding and, thus, guarantee a compensation of the response voltage with respect to the coil heating.
Claims6
In an electromagnetic relay having an excitation coil about a core and a yoke having one end coupled to an end of the core, an armature forms a working air gap with an opposite end of the core, the improvement comprising:
- a permanent magnet mounted to exert a restoring force on the armature by at least one pole of said magnet, said permanent magnet having a negative temperature coefficient of remanence on the order of magnitude of a ferrite magnet;
- a compensating spring opposing the attractive restoring force of said permanent magnet on the armature;
- and
- means for heating being in thermally conductive contact with said permanent magnet, said heating means forming a part of an excitation circuit of the relay.
An electromagnetic relay, comprising:
- a core having first and second opposite ends;
- an excitation coil around said core and connectable to electric power to generate electromagnetic force;
- a yoke having a first end connected at said first end of said core, said yoke extending along said excitation coil substantially parallel to said coil;
- an armature pivotally mounted against said yoke and forming a working air gap with said second end of said core, said armature being pivotable toward said second end of said core upon excitation of said excitation coil;
- a permanent magnet mounted to exert a force on said armature opposite the effect of said excitation coil;
- and
- a heating resistor in thermal contact with said permanent magnet and connected in circuit with said excitation coil.
Dependencies are inferred from the claim text.