Abstract:
There is provided a fan guard for mounting on an electrically-operated axial-flow fan. The fan guard comprises a plurality of fasteners for extending into a plurality of respective holes on the fan and further comprises a projection projecting outwardly from the fan guard from a central support which, in use, is coincident with a central region of the air flow from the axial-flow fan. The fasteners secure the fan guard on the fan by a friction fit between the fasteners and the holes, thereby rendering installation of the fan guard on a fan, and removal of the fan guard from the fan quick and straightforward.
Abstract:
There is described an electronic assembly comprising a structure and a printed circuit board (PCB) connected to the structure to form a duct. The PCB has a first side arranged to receive one or more heat-generating components, and a second side. The PCB comprises one or more apertures formed therein. The electronic assembly further comprises airflow generating means arranged to generate an airflow along the duct and along the second side of the PCB such that air is forced through the one or more apertures. By forming a duct beneath a PCB and allowing air to be forced through apertures formed in the PCB, more efficient cooling of components on the PCB may be achieved. For example, the position of the apertures may be tailored such that specific components, or specific parts of components, may be exposed to airflow through the apertures.
Abstract:
A desaturation detection circuit for use between the desaturation detection input of an optocoupler and the output of a power switching device, the desaturation detection circuit comprising: a threshold setting element having an input and an output, the input for connection to the output of a power switching device via one or more diode(s), the threshold setting element being arranged to set a threshold voltage at the input at which the threshold setting element will provide an output at the output of the threshold setting element when the input voltage is exceeded, and a detector having an input connected to the output of the threshold setting element and an output connectable to a desaturation detection input of an optocoupler, the detector being arranged to detect an output at the output of the threshold setting element and in response to provide a control signal at the output of the detector for the desaturation detection input to trigger a desaturation routine in the optocoupler.
Abstract:
An energy bypass circuit for connection between an energy source and a capacitance has first and second relays, a switch, and a resistance. The relays are operable so as to have a first state in which the energy source is not connected to the capacitance, a second state in which the energy source is connected to the capacitance via the resistance, and a third state in which the energy source is connected to the capacitance not via the resistance. The switch is operable, when the relays are in the third state, to enable additional charge stored by the capacitance to discharge via the resistance.
Abstract:
There is provided a motor drive comprising: a temperature sensor arranged to sense a temperature of the drive; a braking resistor; switching means arranged when activated to cause current to flow to the braking resistor; and controlling means arranged to activate the switching means when the sensed temperature falls below a predetermined threshold. There is also provided a method of controlling a temperature of a motor drive comprising a braking resistor. The method comprising comprises: monitoring a temperature of the drive; and activating switching means to cause current to flow to the braking resistor when the monitored temperature falls below a predetermined threshold.
Abstract:
A device is provided in which messages are received from a backplane through backplane connectors. Switching circuitry identifies which messages received from the backplane are intended for the operational circuitry of the device and interprets the input/output protocol of such messages while returning messages not intended for the operational circuitry to the backplane. The switching circuitry is removable from the device independently of the backplane connectors, allowing it to be changed for use with different backplane protocols without affecting other device elements.
Abstract:
A method comprises: applying control signals to an inverter switching network according to a selected switching sequence, wherein a switching sequence is applied corresponding to a desired sector of a switching scheme in which a demand vector is currently located, the switching scheme corresponding to the demand vector in a space vector modulation scheme having stationary active vectors around the periphery and a stationary zero vector at an origin; storing a plurality of simultaneous switching schemes in which, for a single switching cycle, a switch in each of at least two phases of the inverter switching network is switched simultaneously from a first state to a second state with a corresponding switch in at least one other phase of the inverter switching network being in a given state and in which the switch in each of the at least two phases is switched simultaneously from the second state to the first state with the switch in the at least one other phase being in the given state; and applying a simultaneous switching sequence by applying a first of the simultaneous switching schemes in dependence on the position of the demand vector in relation to the stationary active vectors.
Abstract:
A method of controlling an electrical power supply to a load, wherein said load has an associated power threshold, is provided. The method comprises using a first electrical power source to generate a first amount of power for supply to the load, wherein said first electrical power source comprises a renewable source, and determining whether to supply a second amount of power to the load from a second, different electrical power source. If it is determined that the second electrical power source should be used to supply a second amount of power to the load, controlling an output of the second electrical power source so that a combined amount of power supplied to the load from the first and second electrical power sources meets the power threshold associated with the load.
Abstract:
An apparatus for producing a compensated voltage output comprising: a first power source or power sink coupled between a first node and a reference node; a second power source or power sink coupled between a second node and the reference node; a biasing means comprising one portion coupled between the first node and the reference node, and another portion coupled between the first node and the second node. The biasing means is operable to generate a controllable bias voltage of either polarity between the first and second nodes to produce the compensated voltage output.
Abstract:
An apparatus for connecting two or more circuit boards, the apparatus comprising: a first circuit board comprising a first surface and a second surface, the second surface having a first conductive pad; a second circuit board comprising a third surface and a fourth surface, the third surface having a second conductive pad; a fixing means configured to engage with the first circuit board and the second circuit board to couple the first circuit board to the second circuit board, wherein, when coupled, the fixing means is electrically isolated from one of the first circuit board and the second circuit board; and an electrically conductive spacer configured to electrically couple the first conductive pad and the second conductive pad.