GB2090002A - Relay tester - Google Patents
Relay tester Download PDFInfo
- Publication number
- GB2090002A GB2090002A GB8133754A GB8133754A GB2090002A GB 2090002 A GB2090002 A GB 2090002A GB 8133754 A GB8133754 A GB 8133754A GB 8133754 A GB8133754 A GB 8133754A GB 2090002 A GB2090002 A GB 2090002A
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- GB
- United Kingdom
- Prior art keywords
- digital
- output
- frequency
- phase
- type
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/327—Testing of circuit interrupters, switches or circuit-breakers
- G01R31/3277—Testing of circuit interrupters, switches or circuit-breakers of low voltage devices, e.g. domestic or industrial devices, such as motor protections, relays, rotation switches
- G01R31/3278—Testing of circuit interrupters, switches or circuit-breakers of low voltage devices, e.g. domestic or industrial devices, such as motor protections, relays, rotation switches of relays, solenoids or reed switches
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Testing Electric Properties And Detecting Electric Faults (AREA)
Abstract
A relay tester comprises a digital type frequency varying unit 1a, a pair of digital type frequency varying units 2a, 2a', a pair of function generating circuits 3a, 3a', and a pair of digital type gain varying units 4a, 4a'. At the outputs of the gain varying units 4a, 4a', sine-wave signals of desired frequency, phase and amplitude are provided. The tester further comprises a constant voltage amplifier 5a, a constant current amplifier 6a, a voltage transformer 7a, a current transformer 8a, and a pair of output terminals 11a and 12a for connection to a relay 14a under test. The frequency varying unit 1a, the phase varying units 2a, 2a', and the gain varying units 4a, 4a' are controlled by digital control signals from a control unit 13a. <IMAGE>
Description
SPECIFICATION
Relay tester
This invention relates to relay testers.
A typical example of a conventional relay tester of this type is a slidac type relay tester which comprises a voltage transformer, a current transformer and a slidac and uses a variable frequency generator of several kilo-volt-amperes (KVA) as a test power source. A second example is an analog type relay tester comprising a low frequency oscillator having a small capacity, an analog phase varying unit, an analog type gain varying unit and a power amplifier.
The analog type relay tester is as shown in
Figure 1, and comprises a low frequency oscillator 1 having an oscillator circuit and a frequency adjusting variable resistor VR1; phase varying units 2 each having a phase shift circuit made up of an operational amplifier and a phase adjusting variable resistor VR2; gain varying units 3 each having a gain varying circuit made up of an operational amplifier and a gain adjusting variable resistor VR3; power amplifiers 4; output conversion circuits 5 which are made up of a tapped voltage transformer and a tapped current transformer, respectively; a frequency meter 6; a voltmeter 7; an ammeter 8; a phase meter 9; and output terminals 10 and 11. In Fig. 1, reference numeral 12 designates a device under test, namely, a relay.
The operation of the analog type relay tester is as follows: The low frequency oscillator 1 generates an analog signal of several volts having a desired frequency. In one of the phase varying units 2, an analog signal of several volts having a desired phase is obtained by using the variable resistor VR2 with the output signal of the oscillator 1 as a reference. In one of the gain varying units 3, coupled to the one phase varying unit 2, the output signal of the latter 2 is received, and the gain is adjusted to a desired value by using the variable resistor VR3, so that an analog signal of several volts is outputted. The analog signal thus outputted is too small to drive the device 12 under test. Therefore, the analog signal is applied through a power amplifier 4 to an output conversion circuit 5.The output conversion circuit 5 has taps for determining the dynamic range of its output voltage; i.e., it is so designed as to be able to select a desired dynamic range. The output voltage of the output conversion circuit 5 is applied, as a voltage source, to the output terminal 10, the frequency meter 6, the voltmeter 7 and the phase meter 9, and to the device 12 under test.
On the other hand, a current source is provided for the device 12 under test through the output terminal 11 of the lower circuits 2,3,4 and 5 which are substantially similar in arrangement to the above-described circuits.
As is apparent from the above description, in order to give a static characteristic test to a relay, it is necessary for the operator to manually set the frequency, phase, voltage value and current value with the variable resistors according to the test items of the relay and to monitor indications on the meters to ensure that the proper signal levels are applied. In other words, since the conventional test is arranged as described above, the operator must manually either coarsely or finely adjust the frequency, phase, voltage value and current value to be applied to the relay with the variable resistors while monitoring the meters, which meters must be very accurate to permit accurate control of the applied values.Such a test method, which depends on the operator's intuition and visual detection, not only contributes to the nonuniformity of products, but also hinders working efficiency.
Accordingly, an object of this invention is to eliminate the above-described drawbacks accompanying a conventional relay tester.
According to the invention there is provided a relay tester comprising a digital-type frequency varying unit for generating a digital output signal having a desired frequency determined in accordance with a first digital control signal;
first and second digital-type phase varying units for varying the phase of said digital output signal in accordance with respective second digital control signals to provide first and second digital output signals of desired phases;
first and second function generating circuits for converting the digital output signals of said first and second digitai-type phase varying units into respective first and second analog signals;;
first and second digital-type gain varying units for varying the amplitudes of said first and second analog signals, respectively, to provide first and second analog signals of desired amplitudes in accordance with respective third digital control signals;
first and second differential type power amplifiers for amplifying the analog output signals of said first and second digital-type gain varying units, respectively;
first and second transformer means for converting the output signals of said first and second differential type power amplifiers into voltage and current, respectively and a control unit for digitally controlling said first and second digital type phase varying units, and said first and second differential type power amplifiers.
With this construction, the relay tester of the invention is small in size and low in manufacturing cost. Further, with this relay tester, data errors due to personal errors are eliminated, and the working efficiency is improved.
This invention will now be described in more detail, by way of example, with reference to the accompanying drawings in which:
Figure 1 is a block diagram showing one example of a conventional relay tester;
Figure 2 is a block diagram showing one example of a relay tester according to this invention;
Figure 3 is a block diagram showing one example of a digital frequency varying unit in
Figure 2;
Figures 3A and 3B are more detailed diagrams of the components of Figure 3;
Figure 4 is a block diagram showing one example of a digital phase varying unit in Figure 2;
Figure 4A is a more detailed diagram of the components of Figure 4;
Figure 5 is a block diagram showing one example of a function generating circuit in Figure 2.
Figs. 5A and 5B are more detailed diagrams of the components of Fig. 5; and
Fig. 6 is also a block diagram showing one example of a digital gain varying unit in Fig. 2.
One example of a relay tester according to this invention, as shown in Fig. 2, comprises: a digital type frequency varying unit 1 a; digital type phase varying units 2a, 2a'; function generating circuits 3a, 3a'; and digital type gain varying units 4a, 4a'.
The digital type frequency varying unit 1 a, as shown in Fig. 3, comprises: a crystal oscillator
OSC having an oscillation frequency of 3.6 MHz; a synchronous frequency division circuit SD, a frequency division circuit D for subjecting a frequency to 1/100 frequency division; and a digital switch SW for setting a frequency.
As shown in the more detailed diagrams of
Figs. 3A and 3B, the circuit SD may comprise a programmabie frequency division counter which produces a frequency proportional to the digital switch value and is constructed of a pair of SN74167N integrated circuits available from
Texas Instruments end the frequency division circuit D may comprise a SN7490N integrated circuit also available from Texas Instruments. A plurality of these SN7490N counters coupled in cascade will permit division of, e.g.,1/10,1/100, 1/1000, etc. The digital switch in the frequency varying unit, as well as the other digital switches in the apparatus of Fig. 2 may be any one of a number of available switches such as a Sum rotary Switch available from Tateishi Electronics
Co., Ltd. (OMRON).
Each digital type phase varying unit 2a, as shown in Fig. 4, comprises: a binary-to-decimal conversion counter CC1O;AND elements AND1 and AND2; and a digital switch SW. As shown in the more detailed diagram of Fig. 4A, the conversion counter may comprise appropriately connected integrated circuit counters SN7490 and decoders
SN7442 both available from Texas Instruments.
Each function generating circuit 3a, as shown in Fig. 5, comprises: a PLL (phase-locked loop) circuit; a binary-to-hexadecimal conversion counter C,6; a ROM (read-only memory); a D/A (digital-to-analog) conversion circuit; an LPF (lowpass filter); and a phase inversion circuit INV. As shown in Fig. 5A, the PLL may comprise an MC4044 phase detector and MC4042 V/F converter, both available from Motorola, coupled together through a Low Pass Filter, and the 1/N frequency divider may comprise a plurality of
SN74167 integrated circuits available from Texas
Instruments. As shown in Fig. 5B, the conversion counter C16 may comprise tandem SN74161 circuits available from Texas Instruments.
Each digital type gain varying unit 4a, as shown in Fig. 6, comprises: a four-quandrant type digitalto-analog converter D/A; and a digital switch SW.
The design and operation of D/A converters such as used herein are well known and need not be described in detail.
The relay tester further comprises: a constant voltage power amplifier 5a; a constant current amplifier 6a; a voltage transformer 7a; a current transformer 8a; a power transformer 9a for a high accuracy instrument; a current transformer 1 Oa for a high accuracy instrument; output terminals 11 a and 12a; and a digital control unit 13a; including, e.g., a microprocessor, memories and a printer.
In Fig. 2, reference character 1 4a designates a device to be tested, namely, a relay under test; and 15a, an operating signal line.
The operation of the relay tester thus organized will be described with reference to Figs. 2 through 6. In the frequency varying unit 1 a arranged as shown in Fig. 3, the output signal of the crystal oscillator is of a reference frequency 3.5 KHz. The output signal is applied to the synchronous frequency division circuit SD as a result of which a frequency proportional to a frequency fwhich is set by the two-digit digital switch SW is provided.
The frequency thus provided is subjected to 1/100 frequency division in 1/100 frequency division counter DIV. Thus, the output frequency F of the counter DIV may be:
F=3.6 MHz x (f/102) x 1/1 0O=360f (Hz) The frequency F thus obtained is applied to the binary-to- decimal counter C,O in the phase varying unit in Fig. 4, so that is is converted into a decimal number in a known manner. The output of the counter C,O is applied to the AND circuit AND1 which is opened with a decimal number "360".
The output of the AND circuit AND, is applied to the reset terminal of the counter C1O. Thus, the input signal frequency F (=360F) is divided by 360, and the desired frequency f is obtained at the output of AND,. On the other hand, the output of the binary-to-decimal counter C10 is further applied to the AND circuit AND2 through the digital switch SW, as a result of which a value set by the digital switch SW is provided, as a leading phase signal, by the AND circuit AND2 with the output signal of the AND circuit AND, as a reference. It goes without saying that, in this case, the frequency is completely equal to the aforementioned value f.
In the function generating circuit, the output signal of the AND circuit AND2 in the phase varying unit is applied to the PLL circuit. The PLL circuit comprises a phase synchronous detector and a V-F (voltage-to-frequency) converter frequency division circuit, which cooperate to multiply an input frequency by a factor of N. The output signal of the PLL circuit, i.e. the multiplied signal, is converted into a hexadecimal number in the binary-to-hexadecimal counter C16. The output of the counter C,6 is applied to the address setting bus of the read-only memory (ROM). The
ROM stores hexadecimal representations of discrete portions of half wave components of a sine wave, so that a hexadecimal digital signal is provided at the output of the read-only memory.
These hexadecimal digital signals are applied to the D/A converter D/A, as a result of which the half wave of the sine wave is constructed. The half wave signal is applied to the inversion circuit INV which alternately inverts the half sine wave, and to the low-pass filter LPF, to obtain a full sine wave
AC signal with a low distortion factor. The inversion signal for the inversion circuit is provided by the most significant bit of the output of the binary-to-hexadecimal counter C,6.
In the digital type gain varying unit, the sine wave AC signal mentioned above is applied, as a reference input signal, to an input terminal VIN of the four-quadrant type digital-to-analog converter
D/A. When digital data "D" is applied to the input data bus of the converter D/A by the digital switch
SW, and AC signal V OUT is provided at the output of the operational amplifier OP through the outputs OUT, and OUT2 of the converters D/A. The
AC signal VOUT is:
VOUT=VIN x 1/"D".
The power amplifier 5a is formed as a differential amplifier which receives the output signal of several volts from the above-described digital type gain varying unit 4a and to which the output voltage is fed back through the power transformer 9a for a high accuracy instrument.
Thus, the input/output relationship of the power amplifier 5a is excellent in linearity. The output of the power amplifier 5a is applied, as a voltage source, to the device under test through the ouput terminal 11 a.
On the other hand, similarly as in the case of the voltage source, a current source is provided for the device under test by the power amplifier 6a with the aid of its preceding digital type phase varying unit 2a', function generating circuit 3' and digital type gain varying unit 4a'. The power amplifier 6a is of a power feed-back type. In other words, similarly as in the case of the power amplifier 5a, the output of power amplifier 6a is applied to the feed-back circuit through the current transformer 1 Oa for a high accuracy instrument Therefore, the power amplifier 6a is also excellent in the linearity of its input/output characteristic. The output of the power amplifier 6a is applied, as the current source, to device under test through the output terminal 12a.
With this arrangement, the voltage source and the current source are provided for the device under test through respective output terminals 11 a and 12a. These voltage and current values are provided with high accuracy as determined by the digital signals from the digital switches SW and the control unit 13a. Therefore, functions equivalent to those of measuring instruments can be obtained by reading the digital signals set, and it is unnecessary to provide high accuracy meters such as a frequency meter, a phase meter, a voltmeter and an ammeter which are required in the conventional relay tester to monitor the applied values. I.e., all that is necessary is to provide relay performance monitoring meters which need not be so high in accuracy.
If a program is stored in advance in the memory circuit of the control unit, then a relay can be tested automatically and quickly. The specific programming needed for the control circuit, which control circuit is only necessary if automatic operation is desired, is obviously quite simple since it merely involves the changing of switch values to desired values. Accordingly, the programming need not be disclosed in detail herein.
The invention has been described with reference to a single phase tester. However, the technical concept of the invention can be equally applied to a multi-phase tester. That is, if the digital type frequency varying unit 1 a is commonly used and the other units are circuits 2a-1 2a are provided in as many sets as the number of phases of the polyphase tester, then these other sets of units can 11 be equally operated with respect to voltage and current but with different phases determined by the digital switch in the units 2a, 2a'.
As is apparent from the above description, according to the invention, the relay tester is so designed that frequency, phase, voltage and current to be applied to a relay are set in a digital mode and supplied as accurately as in the case of measuring instruments. Therefore, it is unnecessary to provide high accuracy measuring instruments, and therefore the relay tester can be manufactured small in size and low in cost.
Furthermore, if the device is automatically operated by a micro-process, data errors attributable to personal errors are eliminated, and therefore the test results are reliable and the work efficiency is improved.
Claims (9)
1. A relay tester comprising:
a digital-type frequency varying unit for generating a digital output signal having a desired frequency determined in accordance with a first digital control signal;
first and second digital-type phase varying units for varying the phase of said digital output signal in accordance with respective second digital control signals to provide first and second digital output signals of desired phases;
first and second function generating circuits for converting the digital output signals of said first and second digital-type phase varying units into respective first and second analog signals;
first and second digital-type gain varying units for varying the amplitudes of said first and second analog signals, respectively, to provide first and second analog signals of desired amplitude in accordance with respective third digital control signals;;
first and second differential type power amplifiers for amplifying the analog output signals of said first and second digital-type gain varying units, respectively;
first and second transformer means for converting the output signals of said first and second differential type power amplifiers into voltage and current, respectively, and a control unit for digitally controlling said first and second digital type-phase varying units, and said first and second differential type power amplifiers.
2. A relay tester as claimed in Claim 1, further comprising a plurality of sets of first and second digital type phase varying units and respective first and second function generating circuits, differential type power amplifiers and transformer means, and wherein the output signal from said digital type frequency varying unit is provided commoniy to each of said sets.
3. A relay tester as claimed in Claim 1, wherein said first and second analog signals have said desired frequency and phase.
4. A relay tester as claimed in Claim 1, wherein said digital-type frequency varying unit comprises a digital switch and a programmable synchronous divider programmed by an output from said switch.
5. A relay tester as claimed in Claim 1, wherein each of said digital-type phase varying units comprises
digital counter means for receiving said digital output signal:
conversion means for converting said digital signal to a decimal output;
reset means for resetting said counter means in response to a predetermined decimal output; and
decoder means for providing a signal with said desired phase.
6. A relay tester as claimed in claim 5, wherein each of said digital-type phase varying units further comprises a second digital switch for
providing an output signal representing a desired
phase, and said decoder means is adjustable in accordance with the value of said second digital switch output.
7. A relay tester as claimed in claim 1 , wherein each of said function generating circuits comprises circuit means for providing a digital signal phase locked to the output of said phase varying unit and having a frequency N times the frequency of said phase varying unit output, means for generating an address signal changing at said N times frequency, a memory addressed by said address signal for providing a sequence of outputs at said N times frequency, and D/A conversion means for converting said sequence of outputs into said analog signals.
8. A relay tester as claimed in claim 1, wherein each of said digital-type gain variation units comprises a digital-to-analog converter for
converting a digital value into an analog voltage in accordance with a reference signal, said digital-to-analog converter receiving said function generator output as said reference signal, and a variable digital switch for providing said digital value to said digital-to-analog
converter.
9. A relay tester substantially as hereinbefore described with reference to and as shown in Figure 2, 3, 3A, 3B, 4, 4A, 5, 5A, 5B and 6 of the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8133754A GB2090002B (en) | 1981-11-09 | 1981-11-09 | Relay tester |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8133754A GB2090002B (en) | 1981-11-09 | 1981-11-09 | Relay tester |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2090002A true GB2090002A (en) | 1982-06-30 |
| GB2090002B GB2090002B (en) | 1984-09-26 |
Family
ID=10525736
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8133754A Expired GB2090002B (en) | 1981-11-09 | 1981-11-09 | Relay tester |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2090002B (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2160984A (en) * | 1984-05-04 | 1986-01-02 | Seba Mess Ortungstech | A signal generator for use in underground mining for testing and adjusting measured-value transmitters |
| EP0298865A1 (en) * | 1987-07-09 | 1989-01-11 | Commissariat A L'energie Atomique | Automatic system for the endurance-testing of a plurality of electrical conducting elements |
| GB2215067A (en) * | 1988-02-19 | 1989-09-13 | Richard Carlile Marshall | Testing electrical systems |
| DE4208613A1 (en) * | 1992-03-18 | 1993-09-23 | Asea Brown Boveri | METHOD FOR DETERMINING ACTUAL TRIGGER CHARACTERISTICS |
| EP2237056A1 (en) * | 2008-01-11 | 2010-10-06 | Mitsubishi Heavy Industries, Ltd. | Operation status diagnosing device for external control means |
| WO2019238403A1 (en) * | 2018-06-15 | 2019-12-19 | Phoenix Contact Gmbh & Co. Kg | Switching monitoring device |
| CN113433452A (en) * | 2021-06-23 | 2021-09-24 | 云南电网有限责任公司电力科学研究院 | Automatic phase-changing device of three-phase inconsistent time relay for testing climate laboratory |
-
1981
- 1981-11-09 GB GB8133754A patent/GB2090002B/en not_active Expired
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2160984A (en) * | 1984-05-04 | 1986-01-02 | Seba Mess Ortungstech | A signal generator for use in underground mining for testing and adjusting measured-value transmitters |
| EP0298865A1 (en) * | 1987-07-09 | 1989-01-11 | Commissariat A L'energie Atomique | Automatic system for the endurance-testing of a plurality of electrical conducting elements |
| FR2617975A1 (en) * | 1987-07-09 | 1989-01-13 | Commissariat Energie Atomique | AUTOMATIC SYSTEM FOR ENDURANCE TESTING OF A PLURALITY OF CONDUCTIVE ELECTRICAL ELEMENTS |
| GB2215067A (en) * | 1988-02-19 | 1989-09-13 | Richard Carlile Marshall | Testing electrical systems |
| US4973911A (en) * | 1988-02-19 | 1990-11-27 | Marshall Richard C | Apparatus for electromagnetic compatibility testing |
| GB2215067B (en) * | 1988-02-19 | 1992-09-09 | Richard Carlile Marshall | Electromagnetic compatibility testing |
| DE4208613A1 (en) * | 1992-03-18 | 1993-09-23 | Asea Brown Boveri | METHOD FOR DETERMINING ACTUAL TRIGGER CHARACTERISTICS |
| US5382906A (en) * | 1992-03-18 | 1995-01-17 | Asea Brown Boveri Ltd. | Method for determining an actual tripping characteristic of a relay |
| EP2237056A1 (en) * | 2008-01-11 | 2010-10-06 | Mitsubishi Heavy Industries, Ltd. | Operation status diagnosing device for external control means |
| EP2237056A4 (en) * | 2008-01-11 | 2014-02-05 | Mitsubishi Heavy Ind Ltd | Operation status diagnosing device for external control means |
| WO2019238403A1 (en) * | 2018-06-15 | 2019-12-19 | Phoenix Contact Gmbh & Co. Kg | Switching monitoring device |
| US11774501B2 (en) | 2018-06-15 | 2023-10-03 | Phoenix Contact Gmbh & Co. Kg | Switching monitoring device |
| CN113433452A (en) * | 2021-06-23 | 2021-09-24 | 云南电网有限责任公司电力科学研究院 | Automatic phase-changing device of three-phase inconsistent time relay for testing climate laboratory |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2090002B (en) | 1984-09-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |