A protection apparatus and a brushless motor system reduce costs of the brushless motor system and ensure normal operation of a brushless motor. The protection apparatus includes a demagnetization apparatus and a control apparatus. The demagnetization apparatus is configured to be bridged between a rectifier circuit and an excitation winding, and is configured to consume, when the brushless motor system is faulty, excess electric energy generated on the excitation winding. The control apparatus is configured to separately connect to an excitation power supply circuit and a controller; and is configured to detect electrical parameters of an input terminal and an output terminal of the excitation power supply circuit, and when determining that the electrical parameters exceed a preset threshold, generate an alarm to the controller and adjust the output electrical parameter of the excitation power supply circuit.

The present invention discloses a device for evaluating and demagnetizing residual magnetism quantity of a power transformer. A main circuit comprises a switching power supply the two ends of which are respectively connected with a filter capacitor and a resistor in parallel. A forward end of the switching power supply is connected with a main switch in series. A rear end of the main switch is connected with a series branch of a sixth switch and a first resistor, a series branch of a first switch and a second switch, and a series branch of a third switch and a fourth switch are connected in parallel. A driving circuit is respectively connected with driving ends of the main switch, the sixth, first, second, third and fourth switches. A control circuit is connected with the driving circuit for sending an instruction to the driving circuit.

A demagnetization method for a multilayer shielding apparatus is provided. In the demagnetization method, the demagnetization is realized on the basis of a demagnetization coil system. The demagnetization coil system includes a plurality of turns of demagnetization coils (2), a plurality of connection wires and a power supply module. The multilayer shielding apparatus includes at least two layers of shielding bodies (1); all the layers of shielding bodies (1) are sleeved layer by layer from inside to outside; a plurality of turns of demagnetization coils (2) are wound on each layer of shielding bodies (1) at intervals; and one half of each turn of demagnetization coils (2) is located inside the wound shielding bodies (1), and the other half is located outside the wound shielding bodies (1). Each demagnetization coil (2) is connected to the power supply module through the corresponding connection wire.

A manufacturing method for a cylinder device which includes a cylinder, a piston, a piston rod, a seal member, and an installing member, the method includes: a welding step for fixing the installing member to the cylinder through electrical resistance welding; a demagnetizing step for demagnetizing at least an opening portion of the cylinder; and an assembling step for assembling the piston, the piston rod, and the seal member in the cylinder through the opening portion.

A pipeline demagnetization device based on a permanent magnet structure includes a central piece and permanent magnets distributed on the central piece. A magnetic field with alternating directions is formed in a wall of a pipeline in an axial direction from front to back, and strength of the magnetic field gradually decreases. The pipeline demagnetization device can be applied to the pipeline demagnetization using a built-in structure or an externally-built structure. The pipeline demagnetization device spatially constructs a set of stable alternately-decayed magnetic fields, so that the wall of the pipeline experiences the set of alternately-decayed magnetic fields when the pipeline that is magnetized spatially displaces relative to the set of alternately-decayed magnetic fields, thereby realizing demagnetization.

The present disclosure relates to a circuit device for demagnetizing the rotor of an externally excited synchronous machine and to a method for operating the circuit device.

Embodiments of a discharge circuit are disclosed for quickly and safely discharging energy from an inductor load. The discharge circuit comprises a first switch, a second switch and a voltage regulator. The inductor load couples between the first switch and the second switch. During fast demagnetization, a high side switch is tuned off to decouple the load from a voltage source and the second switch is turned on. Voltage on one end of the load is pushed high and maintained at a predetermined level due to the voltage regulator. The predetermined voltage pulls down the current at the inductive load and causes temperature of the discharge circuit going up quickly. Once the temperature reaches a predetermined threshold, a comparing circuit outputs a signal to a driver and eventually pulls down voltage of the inductor load for low-power demagnetization.

An integrated circuit for demagnetizing an inductive load includes a first switch to control current supplied by a voltage supply to the inductive load. A Zener diode includes an anode connected to a control terminal of the first switch and a cathode connected to the voltage supply. A second switch includes a control terminal and first and second terminals. A temperature sensing circuit is configured to sense a temperature of the first switch and to generate a sensed temperature. A comparing circuit includes inputs that receive a reference temperature and the sensed temperature and an output connected to the control terminal of the second switch.

A system and a method for separating and recycling magnets made from rare earth elements from an article of manufacture used an alignment device to property position the rare earth magnet for processing. Once proper alignment is made, a separating device removes the magnet and a portion of the article. A heating device demagnetizes the magnets and vibration causes the magnets to separate from the portion of the article. Electromagnets remove the portion of the article and the rare earth magnets pass through for reclamation.

De-magnetization protection is provided for electro-permanent magnets during information handling system manufacture and use by monitoring thermal conditions at the information handling systems to detect a thermal state associated with de-magnetization and commanding the electro-permanent magnets to an off state so that both magnets in the electro-permanent magnet have opposing polarities. The opposing polarities tend to stabilize magnet polarity to prevent de-magnetization during increased temperatures. Normal operations are then re-enabled once temperatures decrease.