Abstract:
A low-filter is arranged for attachment to an exterior face of a wall of an electrically conducting screened chamber encasing the magnetron and an associated isolation transformer electrically connected to terminals of the magnetron. Output connections of the filter pass directly through an interface between the electrically conducting screened chamber and the filter to connect electrically, directly or indirectly, with the isolation transformer. There are therefore no electrical leads outside the screened chamber electrically connecting the filter to the isolation transformer.
Abstract:
Drive circuit and method for a gated semiconductor switching device A drive circuit and method for a gated semiconductor switching device (10) comprising providing coupling such as a mutual inductance between a gate drive circuit (21) for the device and a drain to source current supply circuit (22) for the device in order to change a gate voltage provided by the gate drive circuit dependent on a rate of change of a current in the drain to source current supply circuit. The change in gate voltage has a magnitude and phase arranged to increase or decrease a switching speed of the gated semiconductor switching device.
Abstract:
An RF generator power supply comprises a first switched mode power supply (SMPS) connected in series to a second SMPS by a DC bus. A capacitor is arranged between the outputs of the first SMPS and inputs of the second SMPS to act as a smoothing capacitor for the first SMPS and to supply pulse energy to the second SMPS. The second SMPS has an output connected to an input of a step-up transformer and an output of the step-up transformer is connected to an input of a rectifier connectable to the RF generator. An input of the first SMPS is connectable to a prime power supply to maintain a high power factor with low harmonic content while setting an operating voltage and peak current level for the RF generator. The second SMPS is arranged to feed the step-up transformer and is arranged to operate with a variable duty cycle and/or variable frequency to provide average power control of the RF generator. The second SMPS is rapidly switched off on detection of a power surge through the RF generator.
Abstract:
A fire hose coupling comprises a body having a first end connected to a fire hose and a second end having either male or female threads or, alternatively, a quarter-turn sexless coupler. The fire hose coupling comprises a recessed portion formed in an outer surface of the body. The recessed portion is shaped to define a visuotactile directional indicator such as an arrow. The recessed portion may include a light-reflecting surface to enhance visibility such as a super reflective metal film, a photo luminescent coating, or a phosfluorescent coating. The recessed directional indicator may be formed in female, male or sexless (Storz) couplings. Since the light-reflecting directional indicator is recessed, it will not cause the hose assembly to snag or catch when the hose is dragged through a burning structure, nor will the directional indicator abrade or wear over time. This coupling enables firefighters to readily determine the exit direction when operating in dark and smoky conditions.
Abstract:
An enclosure (4) for electrical apparatus (6) has a sealable outlet (8) for partially evacuating the enclosure and a sealable inlet (9)for partially filling the enclosure with a liquid (7) having a vapor pressure at operating temperatures of the apparatus suitable to enhance electrical isolation of the electrical apparatus and suitable to provide convective cooling of the electrical apparatus. The vapor preferably provides a voltage hold-off sufficiently high for operating voltages of the electrical apparatus and has a relative permittivity sufficiently low to prevent stray capacitance in the electrical apparatus above a predetermined limit.
Abstract:
Described herein are systems and methods that test authentication information on a fuel cartridge. A controller on a device that interfaces with the cartridge tests and validates the authentication information before permitting fuel provision from the cartridge. The authentication information can be used to prevent unauthorized cartridges from providing fuel. This permits the device to ensure that the cartridge, its manufacturer, and/or its contents are acceptable. Authentication information stored in a cartridge memory may also be encrypted.
Abstract:
The invention relates to hybrid fuel cell systems that protect a fuel cell with a second electrical energy source. The second electrical energy source powers a load to prevent the fuel cell from witnessing stoichiometric levels that may lead to reductions in fuel cell performance or health. The hybrid fuel cell system includes an electrical circuit that electrically initiates the electrical energy source to provide power to the load in response to detecting a potential stoichiometric disturbance for the fuel cell.
Abstract:
A solid state switching arrangement includes a transmission line which acts as a primary transformer loop and acts with secondary windings carried by switching modules to apply triggering signals to the switches. The arrangement may include greater than sixty modules.
Abstract:
A pulse transformer is used in a radar transmitter to transform a high current pulse at relatively low voltage into a very high voltage pulse which can be used to directly drive a magnetron oscillator. The potential of the output pulse can be of the order of 30 kV and since the transformer is required to operate at very high peak powers of the order of two megawatts, it must be very carefully designed to avoid excessive electrical losses and voltage breakdown. The core material of the transformer consists of a closely wound reel of magnetic material in the form of an elongate tape, which is mechanically fragile. The magnetic core is loosely mounted within a sealed container so that the primary and secondary windings surround it. A conductive shield is placed around the magnetic material so as to protect it from the very large electric fields generated within the transformer. This prevents the ionization of gases which could lead to the rapid deterioration of the magnetic core material.
Abstract:
A transformer includes a primary winding; a secondary winding; a first electrostatic screen located between the primary winding and the secondary winding and most proximate to the primary winding; and a second electrostatic screen located between the primary winding and the secondary winding and most proximate to the secondary winding. The first electrostatic screen is electrically connectable to a power supply electrically connectable to the primary winding and the second electrostatic screen is electrically connectable to a load electrically connectable to the secondary winding. The invention also includes an inverter system including the transformer.