A transistor chopper for controlling the power delivered to a DC load from a DC source includes two or more transistors connected in series between the DC source and the load and means for controlling the voltage across each transistor so that the transistor is subjected to only a fraction of the open circuit voltage developed by the DC source Lower power transistors may therefore be used as switching elements in the chopper, and hence the overall cost of the system is reduced over prior choppers

Series transistor chopper

The present invention relates to a method that comprises dispersing a stream of a melt flowing from a die by applying perturbations to said stream in an inert cooling gas which has an optimal temperature and is depleted from oxygen up to a value not exceeding 0.0001 mol. %. After their output at a stationary generation mode, the granules are recovered in the outlet portion of a heat-exchange chamber. The die is made of a heat-resistant material and has a flow section with a length defined by the relation 2d≤l≤20d. The perturbation frequency of the stream is defined by relation (I) where τ is the dispersion time (at the initial moment τ = 0); c is the empirical coefficient characterising the die material resistance to the perturbation of the stream; w is the flow rate of the stream; do is the initial value of the stream diameter; and Ko is equal to 0.7 and is the value of the non-dimensional wave number. The material to be dispersed consists of a chemically active melted metal or alloy that comprises at least one rare-earth element.

Method for producing mono-dispersed spherical granules

Water power plants

FIELD: electricity.SUBSTANCE: simulator contains at least one programmable DC power source, at least one programmable AC power source, an impulse noise generator, a switching unit, at least one measuring unit, a control unit, a local area network (LAN), a network switch, a data processing server, an insulation monitoring device, remote controls, at least one data acquisition controller, a precise time server connected to a GPS/GLONASS antenna. DC and AC power sources are made suitable for converting incoming electric power to their inputs into output currents with predefined parameters. The outputs of the current sources and the impulse noise generator are connected to the inputs of the switching unit, the outputs of which are configured to communicate with the corresponding inputs of at least one device under test and with at least one measuring unit. The control unit is made in form of an operator's computer work station (CNC), operator's CNC, a data processing server, a remote control, a data acquisition controller, a precise time server, inputs of current sources and an impulse noise generator are connected via LAN through a network switch. The insulation monitoring device is connected to at least one data acquisition controller and is configured to measure the insulation resistance of the simulator circuits. At least one measuring unit is configured to measure the signal characteristics at the output of the switching unit and is connected to a data acquisition controller. A remote control and the operator's CNC are additional configured to transmit information over the loudspeaker network.EFFECT: providing the possibility of carrying out a comprehensive check of various types of equipment on one stand, the possibility of conducting of parallel tests, increasing the flexibility and efficiency of changing the operating modes of the equipment during testing, the ability to provide a minimum delay in the conversion of electricity from the time of the transfer of the relevant command, and also to provide the visualization of measurements and results of tests in real time, a significant quantity reduction of equipment failures in operation due to the identification at the stage of factory testing of equipment containing unstable power supply elements.2 cl, 1 dwg

Supply mains simulator (sms)

The balancer is intended for use in a power supply unit to permit improvement of the balance in an electrical three-phase system, whereby the balancer functions for example as a filter and, when used in a measurement apparatus, to permit the formation of a stable reference point with regard to the amplitude, phase and frequency of electrical quantities in a three-phase system The balancer is characterised specifically in that, for each phase in the three-phase system, it comprises a separate toroidal magnetic core (12, 14 and 16), on which are arranged at least two mutually electrically isolated windings (18, 20; 22, 24; and 26, 28), which are Z-connected

Shidlovskij Anatolij K

Papers

Three-phase mains

Arrangement for pulsed control of d.c.traction motor

Three-phase electric network

Method and apparatus for preparing metal powders

Impulse noise simulator