Patent UA-108285-C2 (UA)
Title: Intrinsically safe devices for the remote control by power consumers
Inventor: BASOV MYKOLA MUSIIOVYCH
IPC: H02J13/00
Filed: 2013-07-15
Abstract: The invention relates to electrical engineering, namely to intrinsically safe devices for the remote control by power consumers, especially by those that are used in hazardous environments. The known remote control devices do not provide the required accuracy of the control of communication line resistance with the control station and reliability of operation, because the threshold of action at increase of abovementioned resistance depends on the parameters of semiconductor elements of these devices, the auxiliary contact of controlled device which reconstructs the mode of device, operation works at low voltages and currents, and executive relays are unstable in an area close to the threshold of action of devices. Intrinsically safe remote control contains an AC power supply, a control station with the contacts of buttons "stop", "start" and the diode, which are series-connected, the communication line, which is connected between the control station and the power source through a current limiting resistor, a comparator, reference signal generating unit, which is connected to the non-reversible input of the comparator, the input signal generating unit, which is designed as an alternating current filter, whose input is connected to the beginning of the line, and an output is connected to the inverting input of the comparator, and the actuating relay that is connected to the comparator output through a DC filter. It is proposed to perform the reference signal generating unit as a voltage divider at resistors, high frequency generator and an amplifier, the output of which is connected to one of the divider shoulder, and the input is connected to the output of abovementioned the generator, divider shoulder is connected to the non-reversible input of the comparator which is shunted to optocoupler outputs and a second amplifier with resistors which which are connected in series with it, and an optocoupler input is included in the coil circuit of actuating relay, and the input of the second amplifier via a diode is connected to the output of the second divider, which is connected through an auxiliary contact of managed device to a power source. It is also proposed to perform a DC filter as an amplifier whose input is connected to the output of the comparator, and an output is connected to the outputs of the two series-connected transistors of the opposite conductivity type which are connected to a power source, and a circuit which includes a capacitor, two diodes and a capacitor, which are connected in series wherein the connection points of transistors and diodes are connected to each other, and to connect the coil of actuating relay to the connection points of diodes with capacitors through optocoupler input. The invention provides the increase of voltage of auxiliary contacts of managed device and of the current in them by the second voltage divider, the decrease of the threshold of action when a current appears in the coil of the actuating relay via the optocoupler and thus to prevent the emergence of unstable areas of the relay, therefore to provide reliable operation of the device, forming a reference signal by the divider on resistors which enables the required accuracy of the control of communication line resistance with the control station.