Abstract: A device and method for degassing an on-load tap-changer (OLTC) of a transformer for convenient on-site operation. The degassing device includes an OLTC. The OLTC is respectively connected with an oil suction pipe and an oil injection pipe. One end of the oil suction pipe extends to the inside bottom of the OLTC, and the other end of the oil suction pipe extends to the outside of the OLTC to connect with an oil suction and degassing device. One end of the oil injection pipe extends to an upper part inside the OLTC, and the other end of the oil injection pipe extends to the outside of the OLTC to connect with a vacuum oil injection device. The present disclosure has the advantages of convenient on-site operation, excellent degassing effect, simple structure and convenient installation, reduces degassing time and manpower and investment in maintenance, and improves degassing quality.

Abstract: A device and method for degassing an on-load tap-changer (OLTC) of a transformer for convenient on-site operation. The degassing device includes an OLTC. The OLTC is respectively connected with an oil suction pipe and an oil injection pipe. One end of the oil suction pipe extends to the inside bottom of the OLTC, and the other end of the oil suction pipe extends to the outside of the OLTC to connect with an oil suction and degassing device. One end of the oil injection pipe extends to an upper part inside the OLTC, and the other end of the oil injection pipe extends to the outside of the OLTC to connect with a vacuum oil injection device. The present disclosure has the advantages of convenient on-site operation, excellent degassing effect, simple structure and convenient installation, reduces degassing time and manpower and investment in maintenance, and improves degassing quality.

Abstract: A driver circuit, comprising: an input for receiving an input power; an input capacitor (C2) for buffering the input power; a switched mode power converter for supplying a driving current from the buffered input power; a current limiter coupled to the switched mode power converter, wherein the current is configured to control the switched mode power converter to limit the driving current at a driving load limit, wherein the current limiter comprises a controllable switch (Q3) configured to control the switched mode power converter; and a control element (301) configured to sense a variation of the input power, the control element coupled to the controllable switch and adjusting the controllable switch based on the variation of the input power, such that the current limiter is configured to adjust the driving load limit based on the variation of the input power, wherein said control element comprises: a current sensing element (R1) in series in the line between the input capacitor (C2) and the input.

Abstract: To protect electromagnetic ballasts against damage, driver circuits for coupling the electromagnetic ballasts to light circuits comprising light emitting diodes are provided with rectifier bridges for exchanging first current signals with the electromagnetic ballasts and for providing second current signals to the light circuits, and with protection circuits for protecting the electromagnetic ballasts against parameters of the first current signals obtaining values larger than threshold values. The parameters may be direct-current components of the first current signals and may be average values of rectified versions of the first current signals/peak values of the first current signals. The rectifier bridges may comprise first diode elements. The protection circuits may comprise second diode elements serially coupled to the first diode elements.

Abstract: To protect electromagnetic ballasts (2) against damage, driver circuits (1) for coupling the electromagnetic ballasts (2) to light circuits (3) comprising light emitting diodes are provided with rectifier bridges (11-14) for exchanging first current signals with the electromagnetic ballasts (2) and for providing second current signals to the light circuits (3), and with protection circuits (21-24, 25-27) for protecting the electromagnetic ballasts (3) against parameters of the first current signals obtaining values larger than threshold values. The parameters may be direct-current components of the first current signals and may be average values of rectified versions of the first current signals/peak values of the first current signals. The rectifier bridges (11-14) may comprise first diode elements. The protection circuits (21-24, 25-27) may comprise second diode elements serially coupled to the first diode elements.