GB2124786A - Testing device for circuit breakers - Google Patents
Testing device for circuit breakers Download PDFInfo
- Publication number
- GB2124786A GB2124786A GB08222384A GB8222384A GB2124786A GB 2124786 A GB2124786 A GB 2124786A GB 08222384 A GB08222384 A GB 08222384A GB 8222384 A GB8222384 A GB 8222384A GB 2124786 A GB2124786 A GB 2124786A
- Authority
- GB
- United Kingdom
- Prior art keywords
- earth
- circuit
- current
- testing device
- appliance
- 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.)
- Withdrawn
Links
- 238000012360 testing method Methods 0.000 title claims abstract description 18
- 238000000819 phase cycle Methods 0.000 claims abstract description 8
- 238000002347 injection Methods 0.000 claims abstract description 3
- 239000007924 injection Substances 0.000 claims abstract description 3
- 230000003213 activating effect Effects 0.000 claims description 2
- 238000012544 monitoring process Methods 0.000 description 11
- 238000010586 diagram Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229920000136 polysorbate Polymers 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
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
Abstract
A testing device for circuit breakers, wherein an earth loop can be tested includes a switch (32) which controls the value of the resistance inserted in the earth loop, whereby the circuit breaker opening resistance can be checked. A variable current injection arrangement (26, VR1, 28) enables a variable current to be injected into the earth circuit in order to ensure that the trip is operable if an appliance/ earth voltage should build up. A phase sequence tester (21) determines the phase relationship of a power supply 1. <IMAGE>
Description
SPECIFICATION
Testing device for circuit breakers
This invention relates to testing devices for circuit breakers.
In order that electric shock to users of metal encased electrical appliances can be avoided, cases of such appliances are commonly connected to earth via a circuit breaker which causes power to the applicance to be disconnected when the appliance casing becomes live. In order for the circuit breaker to operate effectively, there has to be a good earth from the appliance and if this earth should become disconnected, then the appliance should become disconnected.
One form of earth circuit breaker includes an earth loop monitoring circuit, which when broken, causes an appliance to be disconnected. The earth loop runs from a monitoring circuit to the casing of the appliance and from a second point on the casing of the appliance to the casing of a testing unit which includes the monitoring circuit. The monitoring circuit monitors the earth loop circuit to the appliance and if the loop impedance deviates from certain prescribed limits, the circuit breaker controlling power to the appliance is tripped.
Further, the monitoring circuit is arranged to check the earth loop before energising of the main circuit to the appliance is allowed and if the check does not indicate a safe earth loop, then power is not supplied to the appliance.
An object of the present invention is to seek to provide a testing device which is able to ensure that the above described arrangement is operating satisfactorily.
According to the present invention, a testing device comprises a circuit for injecting current into an earth loop, current magnitude being variable, switch means being provided to allow injection of the current for testing purposes without activating a safety trip mechanism for safe injected currents.
Advantageously, the device includes means for disposing a variable resistance into the earth loop circuit.
Preferably, the device includes a phase sequence indicator.
An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawing which is a circuit diagram.
In the figure, there is shown a socket 1 from a power source (not shown) which contains an earth monitoring circuit. The power source 1 is 3-phase, having live lines which are indicated by 2, 3 and 4 (red, yellow and blue). The earth loop circuit is connected to line 7 and 8, line 7 being connected via monitoring components to the casing of the power supply and line 8 coming from the casing of the power supply. In normal use of the power supply, the two earth lines to the
appliance are connected to different points
thereon.
The testing device, which is generally
shown in the remainder of the figure, includes a plug 10. The lines 2, 3 and 4 are fed, via
fuses 11, 1 2 and 13, respectively, to a rota
tion test switch 1 5. The switch 1 5 comprises
a switch 1 6 in line 2, a switch 1 7 in line 3
and a switch 1 8 in line 4, actuation of these
switches by a push button 20 causing power
in the lines 2, 3 and 4 to be fed to a phase
sequence indicator 21. The phase sequence
indicator is simply a motor which indicates
phase sequence by the direction in which it
turns.
Line 2 is fed by an on/off switch 25 to the
primary of a transformer 26.
The secondary of transformer 26 is con
nected via a fuse 27, a resistor R1, a variable
resistor VR1, an ammeter 28 and a switch 29
to line 7. A voltmeter 30 measures voltage
between line 7 and line 8. Line 8 is con
nected to the casing of the testing device.
The switch 29 which, in one position feeds
the secondary of transformer 26 to line 7, in
the other position places a resistor network
between lines 7 and 8. The resistor network
comprises resistor R2, resistor R3, in parallel,
resistor R4, resistor R5, resistor R6 and resis
tor R7. The value of resistance between the
lines 7 and 8 is determined by the position of
a resistance selector switch 32.
The switch 29 is a fast acting microswitch.
The earth loop monitoring circuit can be
tested by the device in the following way.
Firstly, the phase sequence can be checked
by actuating the push button 20. Depending
upon the direction of rotation of the phase
sequence indicator 21, the sequence of the
phases can be deduced.
Various values of resistance can be
switched into the earth loop monitoring circuit
by adjustment of the selector switch 32. By
seiecting appropriate values of resistance be
tween the lines 7 and 8, the earth loop circuit
can be checked to ensure that it complies with
its design operation. Thus, if a value of say 7
ohms is inserted between lines 7 and 8, then
the earth monitoring circuit should not cause
the power supply to the appliance to be cut
off. However, if the resistance increases to say 1 8 ohms, then power should be cut off be
cause this indicates that the earth circuit is
not correct, giving the possibility of a shock to
an operator. Consequently, when a resistance
of say 7 ohms is inserted in the earth monitor
ing circuit, the power supply trip can be
checked to see whether it operates-it should
not.Likewise when a resistance of 1 8 ohms is
inserted between lines 7 and 8, then the trip
unit can be checked to ensure that it does
operate.
In certain fault conditions, a line to earth
fault on the appliance might feed current via
the earth line 7, through the circuit, thus maintaining the circuit breaker inoperative.
However, the supply 1 contains a current trip which overcomes this condition by operating with a current corresponding to a selected potential difference, say to the 1 2 volts between the tool casing and line 8.
It is therefore important that the power supply can be checked by injecting a current into line 7 to ensure that if the current is too great that the circuit breakers open. The present invention is able to do this by injecting a current from the transformer 26. The magnitude of the current is selected by adjusting the variable resistor VR1. Initially, the value of current is selected so as to be within the safe operation tolerance of the power supply, then the current is gradually increased. At the point that the circuit breaker opens, the values of current and voltage are noted. These values can then be checked to ensure that the power supply is operating in accordance with its design values.
It is to be understood, that the circuitry described above could conveniently be positioned in a small portable testing device. The device could contain solid state circuitry for recording the values of voltage and current at which the circuit breaker opened in the last of the above described test. Further, the tester could be controlled by a microprocessor to operate a testing programme on the push of a button, all the necessary factors being recorded in a memory, such factors including direction of rotation, the resistance at which the circuit breaker opened and also the value of injected current at which the circuit breakers open.
From the above description, it can be seen that the present invention provides an improved testing device for circuit breakers.
Claims (4)
1. A testing device comprising a circuit for injecting current into an earth loop, current magnitude being variable, switch means being provided to allow injection of the current for testing purposes without activating a safety trip mechanism for safe injected currents.
2. A device as claimed in claim 1, including means for disposing a variable resistance into the earth loop circuit.
3. A device as claimed in claim 1 or 2, in which the device includes a phase sequence indicator.
4. A testing device substantially as hereinbefore described and as shown in the accompanying drawing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08222384A GB2124786A (en) | 1982-08-03 | 1982-08-03 | Testing device for circuit breakers |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08222384A GB2124786A (en) | 1982-08-03 | 1982-08-03 | Testing device for circuit breakers |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2124786A true GB2124786A (en) | 1984-02-22 |
Family
ID=10532081
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08222384A Withdrawn GB2124786A (en) | 1982-08-03 | 1982-08-03 | Testing device for circuit breakers |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2124786A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5334939A (en) * | 1992-11-13 | 1994-08-02 | Cooper Industries, Inc. | Ground fault circuit breaker test circuit for panelboards having minimum penetrations and testing circuit breakers without opening panelboard enclosure |
| FR3026192A1 (en) * | 2014-09-23 | 2016-03-25 | Schneider Electric Ind Sas | METHOD FOR TESTING THE ENTIRE PROTECTIVE CHAIN IN A MEDIUM VOLTAGE ELECTRICAL PROTECTION EQUIPMENT, AND APPARATUS FOR IMPLEMENTING SUCH A METHOD |
| CN111751620A (en) * | 2020-05-14 | 2020-10-09 | 广西电网有限责任公司电力科学研究院 | Self-adaptive detection method for primary circuit of circuit breaker |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1333918A (en) * | 1970-05-02 | 1973-10-17 | Lucas Industries Ltd | Instruments for checking the operation of earth leakage circuit breakers |
| GB1390695A (en) * | 1973-11-05 | 1975-04-16 | Ramage S L | Circuit breaker test apparatus |
| EP0006602A1 (en) * | 1978-07-05 | 1980-01-09 | Gossen Gmbh | Method and circuit for testing current or voltage fault protective switches |
| GB1559535A (en) * | 1976-02-10 | 1980-01-23 | Email Ltd | Electrical test unit |
| GB2049204A (en) * | 1979-04-04 | 1980-12-17 | Madewel Electronic Products Lt | Improvements in or relating to testing devices |
| GB2072861A (en) * | 1980-02-23 | 1981-10-07 | Redsure Elp Ltd | Earth leakage circuit breaker tester |
| GB2079958A (en) * | 1980-07-10 | 1982-01-27 | Ramage Stanley Leonard | Circuit Breaker Test Apparatus |
-
1982
- 1982-08-03 GB GB08222384A patent/GB2124786A/en not_active Withdrawn
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1333918A (en) * | 1970-05-02 | 1973-10-17 | Lucas Industries Ltd | Instruments for checking the operation of earth leakage circuit breakers |
| GB1390695A (en) * | 1973-11-05 | 1975-04-16 | Ramage S L | Circuit breaker test apparatus |
| GB1559535A (en) * | 1976-02-10 | 1980-01-23 | Email Ltd | Electrical test unit |
| EP0006602A1 (en) * | 1978-07-05 | 1980-01-09 | Gossen Gmbh | Method and circuit for testing current or voltage fault protective switches |
| GB2049204A (en) * | 1979-04-04 | 1980-12-17 | Madewel Electronic Products Lt | Improvements in or relating to testing devices |
| GB2072861A (en) * | 1980-02-23 | 1981-10-07 | Redsure Elp Ltd | Earth leakage circuit breaker tester |
| GB2079958A (en) * | 1980-07-10 | 1982-01-27 | Ramage Stanley Leonard | Circuit Breaker Test Apparatus |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5334939A (en) * | 1992-11-13 | 1994-08-02 | Cooper Industries, Inc. | Ground fault circuit breaker test circuit for panelboards having minimum penetrations and testing circuit breakers without opening panelboard enclosure |
| FR3026192A1 (en) * | 2014-09-23 | 2016-03-25 | Schneider Electric Ind Sas | METHOD FOR TESTING THE ENTIRE PROTECTIVE CHAIN IN A MEDIUM VOLTAGE ELECTRICAL PROTECTION EQUIPMENT, AND APPARATUS FOR IMPLEMENTING SUCH A METHOD |
| CN105445573A (en) * | 2014-09-23 | 2016-03-30 | 施耐德电器工业公司 | Method for testing the entire protection chain in medium voltage electrical protection equipment and apparatus for implementing such a method |
| EP3029476A1 (en) * | 2014-09-23 | 2016-06-08 | Schneider Electric Industries SAS | Method for testing the whole of the protection chain in a medium-voltage electrical protection appliance, and appliance for the implementation of such a method. |
| CN105445573B (en) * | 2014-09-23 | 2020-11-13 | 施耐德电器工业公司 | Method for testing the entire protection chain in a medium-voltage electrical protection device and device for implementing same |
| CN111751620A (en) * | 2020-05-14 | 2020-10-09 | 广西电网有限责任公司电力科学研究院 | Self-adaptive detection method for primary circuit of circuit breaker |
| CN111751620B (en) * | 2020-05-14 | 2022-08-16 | 广西电网有限责任公司电力科学研究院 | Self-adaptive detection method for primary circuit of circuit breaker |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |