Short-current protection action current adjusting method and device thereof and device for multi-pole electromagnetic release

A short-circuit protection action current adjusting device for a multi-pole electromagnetic release, comprising a base and a release threshold adjusting device which are common to each pole, a respective electromagnetic system for each pole mounted on the base, respective connecting devices for performing transmission between the release threshold adjusting device and the electromagnetic systems, and respective connecting rods for each pole for transferring a release action, wherein

• each of the electromagnetic systems comprises a coil framework with a hollow cavity, a second static iron core and an auxiliary static iron core fixed at two ends of the hollow cavity of the coil framework, a coil sheathed on the coil framework, a magnetic yoke fixedly connected with the second static iron core and the auxiliary static iron core respectively, a dynamic iron core inside the hollow cavity of the coil framework arranged for linear movement between the second static iron core and the auxiliary static iron core, and a reset spring positioned inside the coil framework by the dynamic iron core and the second static iron core and used for driving the dynamic iron core away from the second static iron core;
• the connecting rod is arranged inside a central hole of the auxiliary static iron core and comprises an inner end fixedly connected to one end of the dynamic iron core and an outer end connected and in linkage to the connecting device;
• a first gap L1 is formed between the auxiliary static iron core and the dynamic iron core, and a second gap L2 is formed between the second static iron core and the dynamic iron core;
• wherein the release threshold adjusting device drives the connecting rod to move the movable dynamic iron core to perform adjustment thereof, a release threshold set by the release threshold adjusting device controls positioning of the dynamic iron core to adjust the first gap L1 and the second gap L2, and satisfy the following variation relationships:
• the thickness of the second gap L2 changes in a direction the same as a size variation of the release threshold, the thickness of the first gap L1 changes oppositely to the size variation of the thickness of the second gap L2, and the sum of the thicknesses of the first gap L1 and the second gap L2 is always kept unchanged, further wherein an elastic force of the reset spring changes oppositely to the size variation of the release threshold;
• wherein when a release current value is adjusted from a larger to a smaller value, a self-induction magnetic energy of the coil reduces in a quadratic relationship mode with electrical current flowing in the coil and an electromagnetic attraction between the dynamic iron core and the second static iron core is increased in a quadratic relationship mode, which is in inverse proportion to reduction of the thickness of the second gap L2;
• wherein adjustment of the release current value and electromagnetic attraction required by actions of the dynamic iron core are in a linear fixed corresponding relationship due to automatically achieved balance between said two quadratic functions.