GB1587043A

GB1587043A - Multi-purpose test set for electrical appliances

Info

Publication number: GB1587043A
Application number: GB11891/78A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-05-23
Filing date: 1978-05-23
Publication date: 1981-03-25

Description

(54) MULTI-PURPOSE TEST SET FOR ELECTRICAL APPLIANCES (71) I, GILBERT HOLMES of 12, Robinson Close, Bishop's Stortford, Hertfordshire and of British Nationality do hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: The multi-purpose test set for electrical appliances (hereinafter called the "test set") is primarily for use with electrical appliances which are terminated with a standard 3-pin household plug (e.g. BS 1363). When an electrical appliance is connected to the "test set" by means of its terminating plug, the "test set" is capable of detecting and indicating the following conditions: (1) Wrongly wired appliance supply cable, i.e. (a) live and earth conductors transposed or (b) neutral and earth conductors transposed.

2 Electrical continuity between; a live and earth conductors b) neutral and earth conductors c) live and neutral conductors.

A spring-loaded captive slot in the front panel of the "test set" enables cartridge fuses of the type BS 1362 to be tested without the use of flying test leads.

The "test set" has an external test lead facility which can be used to check electrical continuity.

Circuit description Figure 1 of the accompanying drawings shows the circuit diagram of the "test set" which is powdered by an internal 9V battery.

Consider an electrical appliance connected to the "test set" via its terminating plug and the socket on the front panel of the "test set", then with S1 in pos. 1: If the live and earth conductors have been erroneously transposed, light emitting diode D1 only will light as current flows through the resistive load of the appliance (any switches on the appliance must be in the "on" position).

If the neutral and earth conductors have been erroneously transposed, light emitting diode (LED) D2 only will light, as described above.

Earthing continuity of the appliance is tested by plugging one of the two flying test leads into any one of the two continuity sockets on the "test set" front panel and touching the body of the appliance under test with the test lead. Diode D1 or D2 will light (depending on which continuity socket is used) if earthing continuity exists. The diode D1 or D2 should be extinguished when the flying test lead is removed from the appliance under test; failure to do so could indicate a wrongly wired plug.

If the appliance plug is correctly wired and electrical continuity exists between live and earth and/or neutral and earth conductors, both LEDs D1 and D2 will light.

Depending upon which conductor offers the least resistive path to the earth conductor, its associated LED will glow brighter. Again the switches on the appliance under test must be in the "on" position in order to extend the electrical continuity test to the internal wiring of the appliance.

With S1 in pos. 2 electrical continuity between the live and neutral conductors of the appliance (applicance must have its switch(es) in the "on" position) is indicated by the lighting of LED D3.

With S1 in pos. 2 and the appliance plug removed from the "test set", cartridge fuses of the type BS 1362 can be placed in the captive slot on the "test set" front panel and tested without the use of flying test leads.

The LED D3 lights if the fuse is intact.

Figure 2 of the accompanying drawings shows a view of the "test set".

Broad idea of the "test set" The "test set" has been conceived and designed especially for people with little or no knowledge of electricity or electrical appliances, in order that such people can, by following simple step-by-step instructions determine if: An electrical appliance terminated by a standard 3-pin plug has an earth fault condition (i.e. electrical continuity between live and earth and/or neutral and earth).

An electrical appliance terminated by a standard 3-pin plug has earthing continuity.

An electrical appliance terminated by a standard 3-pin plug has an open circuit load resistance.

A cartridge fuse of the type BS 1362 is or is not intact.

The "test set" employs water-clear LEDs and electrical continuity in the range of 0-40K# will cause the LEDs to glow. The range of 0-40K# covers the range of most electrical appliances with a resistive load.

Claims

WHAT I CLAIM IS:

1. A portable testing device suitable for determining earth leakage and/or earthing continuity and/or open circuit load conditions on an electrical appliance terminated with a three-pin plug, the device comprising: direct contact means for contacting the pins of the electrical appliance to be tested, which direct contact means has contacts for the respective ones of the earthing, line and neutral pins of such a plug; terminals between which a source of electrical potential can be connected; switching means operable to provide in the first position, an earth leakage series circuit from the first said contact to both of the other said contacts of the said contact means via said terminals, a common current-limiting resistor and indicating means of the said other contacts, the earthing continuity test being provided by means of a flying test lead for contacting the body of the appliance and connected to one of the said other contacts of the contact means, there being a second position of the switching means providing a second series circuit for testing continuity between said other contacts of said contact means via said terminals, current-limiting resistor and third indicating means.

2. A device according to Claim 1, wherein the said indicating means are lightemitting diodes.

3. A device according to any one of the preceding claims, comprising a receptacle for receiving an electrical cartridge fuse, the said receptacle having a second contact means for contacting the contacts of such a fuse to be tested, the second said contact means being mechanically spring-loaded, the second said series circuit and third indicating means providing the continuity testing circuit via the second said contact means.

4. A device according to any one of the preceding claims comprising two points for the attachment, one to each point, of two flying test leads, where either of the said flying test leads, attached to the body of the appliance, provides an earthing continuity test via the first said series circuit, with the second said series circuit, in conjunction with the said flying test leads, providing an electrical continuity testing facility.

5. A device according to any one of the preceding claims wherein the first said contact means is a three-pin electrical socket having individual earth, live and neutral contacts.

6. A device according to any one of the preceding claims and including a D.C. battery connected between the said terminals.

7. A portable testing device substantially as hereinbefore described with reference to the accompanying drawings.