Abstract: An Automatic Transfer Switch (ATS) for a single phase power generator has been designed to enable the automatic operation and transfer of power supply between a public utility supply and a power generator. The ATS, which is a switchgear control system, provides a functional system that provides an automatic switching of power supply between a primary source (public utility) and a secondary power source (generator). The methods employed in designing the ATS involve the use of electromechanical type relays, contactors, voltage monitoring relays and delay timer relays as main components of the system. Incorporated in the ATS is a digital multimeter (DMM) made up of a 12V d.c and a 5V d.c power supply unit, precision rectifier unit, current transformer and Microcontroller (PIC 16F877) to convert the measured analogue alternating current(a.c). voltage and current quantities to digital values for display on the liquid crystal display (LCD). The result of the automatic transfer switch demonstrates its ability to perform automatic power change over activities easily and with little or no human interaction

Abstract: The utility model relates to a tester for electromagnetic relays, which comprises an industrial flat computer, a digital multimeter, a program control voltage source, a time test module, a control module, a test mainboard and a connector, wherein the industrial flat computer is respectively connected with the digital multimeter, the program control voltage source and the control module through recommended standard 232 (RS232) interfaces, and the test mainboard is respectively connected with the digital multimeter, the program control voltage source, the time test module, the control module and the connector. The tester for the electromagnetic relays is a comprehensive test instrument which is capable of measuring various electromagnetic relays comprising as many as 8 sets of contacts, which realizes the full-automatic test on the parameters of the coil resistance, the actuating voltage, the contact resistance and the actuating time of the electromagnetic relays. The tester for the electromagnetic relays has the characteristics of high degree of automation, short test time, high test accuracy, small size, low cost and the like and can be widely applied to detecting the devices of the electromagnetic relays and screening the electromagnetic relays with higher reliability index requirements.

Abstract: This paper introduces a contactless temperature monitoring device applied to the rotor of generators. Firstly, the importance of rotor temperature monitoring of generators is explained, then the current development of the rotor temperature measurement is also introduced. Secondly, the design of RF Temperature monitoring system for the rotor that we are studying is proposed, and the stability and accuracy of the device are demonstrated by comparing with the data measured by the multimeter. Thirdly, wireless power supply for permanent magnet generators is introduced briefly. Finally, the prospect and the problems of the temperature measurement system are showed.

Abstract: The invention relates to the technical field of checking systems, in particular to an intelligent calibration system for an instrument. The intelligent calibration system comprises that: an AC/DC voltage and current source is connected with an FLUKE 8846A digital multimeter and a meter to be checked; the FLUKE 8846A digital multimeter is connected with a computer through an RS232 interface; and the computer is connected with a printer. The intelligent calibration system for the instrument consists of the RS232 interface, the computer, a computer database and the printer, can keep initial data in a paperless mode, query the initial data at any time and perform intelligent calibration without manual calculation, reduces the calculation errors, and improves the detection accuracy and the working efficiency.

Abstract: The invention belongs to the technical field of electrical measurement and relates to a LABview-based method for measuring temperature-resistivity. The method is characterized by utilizing a T-shaped thermocouple to acquire the temperature of the environment which the resistance material sample to be tested is in and utilizing a voltage value acquisition board to convert the analog signals of the voltage values to digital signals according to the formula and transmit the digital signals to an electronic computer; in the step of current change and output, transmitting the initial current value input into the computer when testing starts or the current value changed after voltage judgment to a current source via a program so that the current source outputs the transmitted current value; in the step of voltage acquisition and judgment, utilizing a digital multimeter to acquire the voltage values of the two ends of the resistance material sample to be tested; and utilizing Ohm's law R=U/I to obtain the resistance and then computing the resistivity according to the formula rho=R*S/L and automatically inputting the measured information and data into the computer and processing and storing the measured information and data. The method has the advantages of accuracy in measurement, intuitive data analysis, simplicity in operation, time conservation, intuitive result display and low cost.

Abstract: The invention relates to automatic test equipment for a lithium battery circuit protective board. In the invention, a computer is unidirectionally connected with a programmable DC (direct current) power supply A, a programmable DC power supply B, a multiplexer and a load circuit respectively through a GPIB-USB (general purpose interface bus-universal serial bus) card; the programmable DC power supply A is respectively connected with the multiplexer and a fixture; the programmable DC power supply B is unidirectionally connected with the multiplexer and is unidirectionally connected with the fixture through the load circuit; the load circuit is unidirectionally connected with the multiplexer; and a multimeter is unidirectionally connected with the fixture and the interface data display of the computer respectively. The automatic test equipment is characterized by adopting full digital control through the computer, has the advantage of accurate and stable test, has an out-of-tolerance alarm function, and can measure different parameters of various protective boards and continuously test 32 yoke plates, thus fundamentally solving the defects of the traditional testing instrument such as slow test speed and large measurement errors.

Abstract: The invention provides a verification and calibration device of a heterotype temperature sensor, comprising a computer, a display thereof, a digital multimeter and a control box with a scanning switch and a control circuit board, wherein the scanning switch is electrically connected with a low-potential program control scanner and a matched electromechanical switching controller. In the invention, the scanning switch in an electromechanical integrative structure is electrically connected with the low-potential program control scanner and the matched electromechanical switching controller, temperature data at the measurement reference end is automatically collected and treated with the computer and a running software thereof, and a thermocouple is calibrated, thereby artificial errors are reduced, the working efficiency is enhanced, and a measurement range of the temperature is widened. Under the condition that a stable temperature field which accords with the calibration requirements can be supplied, with changing of constant-temperature blocks with different sizes, temperature sensors with different sizes and different shapes can be inserted, thereby the calibration problem of the temperature sensor and a surface thermometer which are ultra short or have larger appearance and can not be arranged in a liquid constant temperature bath is solved.

Abstract: The utility model discloses an automatic testing system of an optical module integrated with transmission and reception. A testing device comprises a signal generation analyzer, an optical source, an optical attenuator, a spectrometer, an optical power meter, an eye pattern analyzer, an optical spectrum analyzer, a digital multimeter, a digital direct current power supply, an optical module to be tested, a test motherboard and a master control personal computer (PC) which are all connected with each other. The automatic testing system of the optical module integrated with transmission and reception effectively improves testing efficiency, keeps consistency and accuracy of the testing process, and reduces effects caused by human factors in testing process.

Abstract: A multifunctional electric apparatus parameter test instrument comprises a multimeter, wherein a direct current supply is installed in a multimeter casing; a pair of auxiliary sockets is arranged on the multimeter casing; one pole of the direct current supply is connected with one auxiliary socket; the other pole of the direct current supply is connected with the other auxiliary socket through a switch; the switch is fixed on the multimeter casing; and the wiring test instrument is further equipped with a pair of auxiliary testing wires matched with the auxiliary sockets. One pair of auxiliary testing wires matched with the multimeter and one pair of auxiliary testing wires matched with the auxiliary sockets are connected with the corresponding sockets respectively, then the multimeter can be used for inspecting and judging an electric energy metering return circuit; and the test instrument provided by the utility model can be independently used as the multimeter. The test instrument has the advantages of reasonable and reliable structure and accurate inspection and judgment, and can greatly simplify the processes of tests and inspections for wiring and disconnecting of an electric energy metering device.

Abstract: This paper presents the measurement methods of power consumption, output noise spectrum and Bode diagram. The power consumption is measured through supply current using a ‘FLUKE 289 True RMS Multimeter’. The output thermal noise spectral density and Bode diagrams are measured using high-quality equipment consisting of ‘Network Analyzer HP 4195A’ and computer. The measured data are downloaded from Network Analyzer using GPIB interface bus and Matlab. The measured diagrams are plotted using HPGL format generated by Network Analyzer. The measurements are demonstrated on different examples of fourth-order band-pass (BP) active-RC filters realizations. The devices under measurement were realized using printed circuit boards. It was shown that the new design of filters with single amplifier shows better performance both regarding power consumption and noise than the cascade design.

Abstract: The invention discloses a method for checking the welding quality of a stator winding joint of a large power generator, comprising the following steps: 1) outputting constant 50A direct current by virtue of a 50A transformer direct-current resistance tester so as to be connected with the two ends of the stator winding joint; 2) utilizing a 0.2A-level current divider for measuring current and a direct-current voltmeter to monitor a direct-current value; and 3) measuring the voltages at the two ends of a joint resistor by using a high-accuracy digital multimeter, and converting the voltages into a resistance value. By utilizing the method, the measuring accuracy of the resistance value of the stator winding joint can reach 0.2mu Omega. According to the method disclosed by the invention, the voltages of the two ends of the joint resistor are measured by the high-accuracy digital multimeter so as to improve the accuracy, so that not only can large current be guaranteed, but also the high accuracy is met. The invention provides a method for measuring a resistance value of the welding joint simply, conveniently and accurately, so that the accuracy of the welding joint of a measured winding can be guaranteed, and an accurate resistance value is provided for the welding quality of a bar joint so as to handle the unqualified welding joint in time.

Abstract: The invention discloses a system for testing the conversion efficiencies of power supplies, comprising a tested power supply, an alternating-current power supply which is connected with the tested power supply, a power meter, a computer, a multimeter, a load and a single chip, wherein the power meter is connected between the alternating-current power supply and the tested power supply and is used for measuring input power of the tested power supply; the single chip is connected with a plurality of switch modules; the computer is connected with the single chip so as to send control signals to control the single chip to switch states of the switch modules; the computer is also connected with the multimeter so as to send control signals to control the multimeter to orderly measure to obtain data required by the total output power of the tested power supply; and the conversion efficiency of the tested power supply can be computed by the computer according to data measured by the power meter and the multimeter By means of the system for testing the power supply conversion efficiencies, the conversion efficiencies of the power supplies can be detected automatically and the test efficiency is high

Abstract: To assure the security and reliability of radio fuze, its performance must be test. A performance test system of radio fuze is developed, which is based on the theory of the pushing plate method according to the performance indexes written in the national military standard. The testing system which is composed of dipole antenna, frequency meter, multimeter and oscilloscope can test the main performance parameters of radio fuze. It is proved that the testing system can carry out the performance test of radio fuze steadily.

Abstract: The utility model provides a multifunctional digital multimeter capable of realizing voice storage. The multifunctional digital multimeter comprises a liquid crystal display module, wherein the liquid crystal display module is connected with a resistance measuring circuit, a capacitance measuring circuit, a diode or triode measuring circuit, an inductance measuring circuit, a voltage measuring circuit, a current measuring circuit, a temperature measuring circuit and a voice reporting module respectively, and is also connected with a CPU (Central Processing Unit) controller, and the CPU controller is connected with a frequency measuring circuit, a humidity measuring circuit, a length measuring circuit and a data storage module respectively. Therefore, the multifunctional digital multimeter capable of realizing the voice storage can be used for measuring multiple physical quantities, and can also be used for outputting the physical quantities measured by the measuring circuits in a form of voice, displaying the physical quantities on an interface, storing the physical quantities and the like, so that the multifunctional digital multimeter is convenient for a user to use.

Abstract: The invention relates to pressure sensor parameter acquisition and performance calibration equipment, which comprises a pressing fitting, a signal amplification circuit board, a signal acquisition and transmission circuit board and a computer. A signal output by a semi-finished product sensor on the pressing fitting is connected to the signal amplification circuit board; and the signal passing through the signal amplification circuit board is connected to the signal acquisition and transmission circuit board, and then is transmitted to the computer through the signal acquisition and transmission circuit board. The equipment has the advantages that: 1, the signal amplified by the high-performance signal amplification circuit board subjected to correction of temperature compensation of input offset voltage is adopted, the offset value is far smaller than an accurate value, the resolution of a signal acquired by a 16-bit A/D converter of a 16-bit high-performance singlechip of the signal acquisition and transmission circuit board reaches 1/65,536, the data is readable, the accuracy of the recorded data is far higher than that of data measured by a multimeter or an oscillometer and observed and recorded manually, and the data acquisition time is greatly shortened due to automatic recording; and 2, the product line can be flexibly converted by modifying software parameters and algorithms.

Abstract: Capacitance measurement with integrated instruments (function generator & Digital multimeter) has been designed and developed The unknown capacitance is measured by measuring the voltage across capacitor in RC network The Digital Synthesis Arbitrary Function Generator/Counter (Protek 9305), and Dual Display Multimeter (Escort 3146A) are used as part of instrumentation The function generator and digital multimeter instruments are available in all the labs, by integrating these devices a powerful yet cost effective instrumentation can be evolved This paper describes such an instrument for capacitance measurement MATLAB program interfaces the instruments through serial port and collects data, the applied and measured voltage at particular frequency, the results are analyzed to get corresponding Capacitance of the any capacitor under test The present system will be of great use in industrial environments as well as for engineers in the industries and researchers in organizations

Abstract: The utility model provides an automatic detection system of a temperature sensor/transducer. The automatic detection system comprises a worktable, a liquid crystal display screen, a potential difference meter, a multifunctional digital multimeter, a button, a DC (Direct Current) potential difference meter, a DC power supply and a signal acquiring and processing device, wherein the liquid crystal display screen, the potential difference meter, the multifunctional digital multimeter, the button, the DC potential difference meter, the DC power supply and the signal acquiring and processing device are arranged on the worktable, the DC power supply is connected with the DC potential difference meter, and the liquid crystal display screen, the potential difference meter and the multifunctional digital multimeter are connected with the signal acquiring and processing device. When the automatic detection system of the temperature sensor/transducer is adopted, mass automatic detection functions during the production are realized, a lot of time is saved, the manual mistakes are prevented, and the product quality and production efficiency are improved.

Abstract: The utility model relates to the technical field of inspection equipment, in particular to a high-voltage load box applied to detecting high-voltage tester, wherein the high-voltage load box comprises a box body on which a wiring terminal common end and a wiring terminal high end are arranged; and a high-power high-voltage resistor is connected between the wiring terminal common end and the wiring terminal high end. By matching with multimeter, the high-voltage load box satisfies the condition of outputting high voltage by the high-voltage tester; and the high-voltage load box can be widely applied.

Abstract: PROBLEM TO BE SOLVED: To provide a DC accident point inspection device capable of precisely detecting an accident point even if electrostatic capacitance of a DC circuit, which supplies DC power from a DC power source to a load of a branch circuit connected in parallel, is large. SOLUTION: A reference resistor 22 for generating a reference voltage V for inspection is connected in series to a voltage power supply device 19 which applies an AC voltage for inspecting an accident point to a DC circuit which supplies DC power to a load of a branch circuit connected parallel from a DC power supply. A clamp CT20 for measuring current waveform of the current that flows to the branch circuit of the DC circuit is held by a branch circuit which is to be inspected for accident point among branch circuits of the DC circuit. A vector multimeter 23 displays a current waveform measured with the clamp CT20 and a voltage waveform of the reference voltage generated in a reference resistor. COPYRIGHT: (C)2011,JPO&INPIT

Abstract: A system for testing power conversion efficiency includes a power supply, an Alternating Current (AC) source connected to the power supply, a power meter configured to measure an input power of the power supply, a computer, a multimeter, an electrical load, and a microcontroller. The microcontroller is connected with a plurality of switch modules. The computer is connected to the microcontroller to send control signal that controls the microcontroller to switch the switch modules. The computer further connects to the multimeter to send control signal that controls the multimeter to measure data used for calculating an output power of the power supply. The computer calculates a conversion efficiency of the power supply according to the data measured by the power meter and the multimeter. The system of the present invention is capable of testing the conversion efficiency of the power supply automatically and efficiently.

Abstract: The invention relates to a multifunctional off-line measuring instrument for identifying faults of various low-voltage electrical appliances. Various low-voltage electrical appliances can carry out the fault identification without being arranged in a specific electrical control system, thereby improving the qualified rate of the one-time assembly of the products of the electrical control system and reducing the production cost of the products of the electrical control system. The multifunctional off-line measuring instrument comprises a transformer and is characterized in that: the transformer is provided with output ports which are connected in parallel for outputting different voltages, the output ports are respectively connected with an alternating current coil detection module which is matched with the voltage value, a contact detection module and a multimeter module through a selection switch, and an input port of the transformer is connected with a 380V alternating current motorwinding detection module.

Abstract: A multimeter includes a main body, two probes extending from the main body, a battery unit arranged in the main body, and a charging system arranged in the main body and configured for charging the battery. The charging system includes a microcontroller with an external input voltage sampling circuit, a battery voltage sampling circuit and a voltage regulator circuit each electrically connected the microcontroller. The microcontroller compares sampled signals from the external input voltage sampling circuit and the battery voltage sampling circuit, and controls the voltage regulator circuit to regulate the external input voltage to be applicable to the battery based on the comparison.

Abstract: The utility model relates to a measuring device for an LED (light-emitting diode) derating curve, which belongs to the technical field of thermal property detection of semiconductor photoelectric devices. An LED to be tested, a thermocouple and a clamp are arranged in a constant temperature oven, and the LED to be tested and the thermocouple are arranged at the same position on the clamp. A digital source meter is connected with the LED to be tested, and a digital multimeter is connected with the thermocouple. The digital source meter, the digital multimeter, the clamp and the constant temperature oven are connected with a computer respectively. The digital source meter supplies a positive current to drive the LED to be tested, the constant temperature oven supplies a stable environment temperature, the thermocouple is used for detecting the actual environmental temperature near the LED to be tested, the digital multimeter is used for patrolling the resistance value of the thermocouple, and the computer is used for collecting and processing related data and outputs a graphic derating curve to users. Compared with prior art, the measuring device for the LED derating curve has the advantages of high efficiency, accuracy and wide application range.

Abstract: This article uses the virtual instrument technology,presents the overall structure of the virtual digital multimeter,and works out the design scheme of its hardware and software.It researches the current,voltage and resistance measurement circuit based on the MAXB4 chip in detail,and completes the software design.Finally,it verifies that the accuracy can meet the designed requirements through testing and is more intelligent.

Abstract: The utility model relates to a pointer-type multimeter with ultra-sensitivity, aiming to solve the technical problem through providing a multimeter with the characteristics of high sensitivity, low voltage, simple structure and convenience in use. The technical scheme is that the pointer-type multimeter comprises a shell, a pointer, two probes, a shift switch, a meter head and a shift circuit. The utility model is characterized that a DC signal amplifying circuit is further arranged on the pointer-type multimeter, and comprises the following circuits: an amplifying circuit used for amplifying current of the meter head of the multimeter, a power supply conversion circuit used for supplying working voltage to the amplifying circuit, a voltage-stabilizing circuit and a delay power-off circuit, which are all in sequent connection, wherein the input end of the delay power-off circuit is connected with a battery and the output end of the amplifying circuit is serially connected with the meter head.