GB2422496A

GB2422496A - Power module for self-contained emergency lighting unit

Info

Publication number: GB2422496A
Application number: GB0501025A
Authority: GB
Inventors: Peter Cook; Angus Stone
Original assignee: Cooper Lighting and Security Ltd
Current assignee: Eaton Electrical Systems Ltd
Priority date: 2005-01-19
Filing date: 2005-01-19
Publication date: 2006-07-26
Anticipated expiration: 2025-01-19
Also published as: GB0501025D0; GB2422496B

Abstract

A power module 10 for an emergency lighting luminaire 16 and ballast 18 comprises a mains supply 12 and a centralised battery supply 24. If the mains power supply fails then the emergency lighting module receives power from the central battery supply via a central power pack 30. The system is particularly useful in a system, such as a self-contained emergency lighting unit, which would normally have a local battery (14, figure 1), and where the centralised battery supply replaces the local battery and the local battery charging current is used to charge the central battery power pack.

Description

1 2422496 Emergency Lighting Conversion Module Power Pack This invention

relates to emergency lighting systems and in particular, but not exclusively, to a power pack for a self-contained emergency lighting module.

Emergency lighting may be provided using dedicated emergency light fittings (luminaires) or by using a conversion kit designed for incorporation into a normal mains luminaire.

A popular method of providing emergency lighting is to use a selfcontained conversion kit, which provides power to a is lamp and ballast for driving that lamp. The converted luminaire then has a first power supply in the form of an unswitched mains supply, used to charge a local battery and to allow mains sensing, and a second power supply in the form of a switched mains supply used to operate the lamp under normal conditions. In the event that the mains power supply fails power is provided to the lamp by the battery.

A second type of conversion kit is a central system conversion kit, which in addition to the unswitched mains power supply referred to above has a central battery supply from a centrally located battery, as opposed to a local battery of the self-contained conversion kit referred to above.

In recent years a large variety of new light sources have been introduced on to the market. Each new light source requires its own conversion unit to form the basis of an emergency lighting system. Each unit is needed in order to ensure proper lamp operation and gear compatibility.

It is disadvantageous to have to provide a wide variety of conversion kits.

S

Central battery systems as referred to above have become a small section of the emergency market in favour of increased growth of the use of selfcontained systems, in which a local battery supply is provided. However, this trend may reverse due to environmental issues, including those relating to the control of hazardous substances contained in the batteries. Also, recycling of batteries is easier if the battery is in one place, as in the case of a central battery supply, rather than being dispersed in the form of a larger number of smaller battery units spread throughout a building.

However, it is disadvantageous to provide a range of self- contained kits and a separate range of central battery kits. This problem is exacerbated due to there being several different system voltages used in central battery systems. The provision of such a wide range becomes uneconomic. The normal result of this disadvantage is that central system kits are restricted to a small range, which further inhibits their use.

Self-contained conversion units typically use a range of batteries. In the U.K. the most popular batteries are rated at 4 Ah and are sealed NiCd units in 3, 4, 5 and 6 cells. This provides a three hour duration of lighting via a 1 amp discharge, where the different battery voltages are used to provide different power levels to suit different lamp types and applications. Where continental European 1 hour systems are required this is done either via a higher discharge current from the 4 Ah battery, or more usually using 1.5 Ah batteries and keeping the 1 amp discharge.

It is an object of the present invention to address the above mentioned disadvantages.

This invention addresses the disadvantages referred to above by providing a means to use self-contained emergency lighting conversion kits on central battery systems by the addition of a single module for each emergency lighting unit.

This invention provides a power pack that replaces a local battery of a self-contained emergency lighting conversion kit, but utilises the same conversion module.

According to a first aspect of the invention there is provided a power module for a self-contained emergency lighting module, which power module comprises: a charging current receiving element, operable to receive a battery-charging current from an attached self- contained emergency lighting module; a central supply receiving element operable to receive power from a centralised battery power supply; the power module being operable in an emergency condition to supply power from the centralised battery supply to the attached self-contained emergency lighting module.

The power module is advantageously operable to accept and dissipate a battery-charging current by means of the charging current receiving element, enabled by the s presence of the central supply. This allows the emergency module charge indicator to operate normally - indicating that the normal mains is present and that the power module is connected and that the central supply is connected.

Also the power module advantageously mimics a power supply io from a local battery that is expected by the self- contained emergency lighting module, whereas the power supply is in fact provided to the power module by the centralised battery power supply.

The charging current receiving element may be operable only when the central supply is connected. The charge current receiving element may be inhibited when the centralised battery supply is disconnected or falls outside a rated range.

The power module is preferably more compact than a local battery that it replaces. The reduction in size is advantageous for the retrofitting of the power module in a space made free by removal of, or space not taken up by, a local battery.

The module preferably incorporates output selection means operable to be switched to select an output voltage of the module.

The module preferably incorporates input selection means, which may be operable to select an input current mode, such as AC or DC. The input selection means may be operable to select an input voltage. The selection may be automatic and a mains fail criteria may be set by the emergency module.

According to a second aspect of the present invention there is provided a conversion kit for providing emergency lighting, the conversion kit comprising: a self-contained emergency lighting module; and a power module comprising a charging current receiving element, operable to receive a battery-charging current from an attached self-contained emergency lighting module; a central supply receiving element operable to receive power from a centralised battery power supply; the power module being operable in an emergency condition to supply power from the centralised battery supply to the attached self-contained emergency lighting module.

The conversion kit advantageously takes up less space than a selfcontained emergency lighting module connected to a local-type battery supply.

The invention extends to an emergency lighting system incorporating at least one power module as described in the first aspect, at least one self-contained emergency lighting module and at least one lamp.

The system preferably incorporates a lamp ballast for each lamp.

All of the features described herein may be combined with any of the above aspects, in any combination.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which: Figure 1 is a schematic diagram of a prior art self- contained emergency lighting conversion module; Figure 2 is a schematic diagram of a prior art central system emergency lighting conversion module; and Figure 3 is a schematic diagram of a self-contained emergency lighting conversion module using a battery power supply provided from a central battery supply system via a local power pack.

In Figure 1 a self-contained emergency lighting conversion module 10 has an unswitched mains power supply 12, a power supply from a local battery 14 and supplies a lamp 16 and connects to a ballast 18. Under normal conditions in such a self-contained emergency lighting module 10 mains voltage is supplied to the module 10, which voltage is used to connect normal mains ballast 18 to the lamp 16 and to charge the local battery 14. If the mains supply fails then the module 10 disconnects the normal mains ballast 18 and connects the lamp 16 to an internal inverter (not shown) that uses power from the battery 14 to power the lamp 16 for the required period, which is referred to above may for example be 3 hours.

The disadvantages of such a system are that a large number of batteries 14 is required, i.e. one for each self- contained emergency lighting module 10, which in a typical system may be many tens or hundreds of batteries. The environmental aspects of the dispersal of a large number of batteries containing toxic chemicals are a disadvantage.

The other type of emergency lighting module used is shown in Figure 2, in which a central system emergency lighting module 20 has an unswitched mains power supply 22 and a power supply from a central battery supply 24. The module powers a lamp 26 and provides connection for the corresponding ballast for the lamp 28. The central system emergency lighting module 20 works in a similar way to the self-contained emergency lighting module 10 described in relation to Figure 1. Mains voltage is supplied from the unswitched mains supply 22 to the central system conversion module 20, which connects the normal ballast 28 to the lamp 26. Charging of the central battery 24 is not performed by the central system emergency lighting module 20, but rather is done centrally at the location of the central battery 24.

The disadvantages of the central system emergency lighting module are that a large number of modules 20 must be produced to account for the wide variety of light sources that is available. The low volume of production of the central system emergency lighting setups gives rise to a disadvantageously high cost of production, despite the environmental benefits referred to above.

In order to provide an emergency lighting module that has the advantages of the large volume of self-contained emergency lighting module systems and the central system emergency lighting module systems the setup shown in Figure 3 has been devised. A self-contained emergency lighting module 10 has an unswitched mains power supply 12. The module 10 supplies a lamp 16 and ballast 18 in the usual way. As referred to above the self-contained emergency lighting module 10 provides an output power for a local battery, which in the embodiment shown in Figure 3 is not present. Instead, in the absence of the unswitched mains power supply 12, the emergency lighting module 10 receives battery power from a central battery supply 24 via a central battery power pack 30, which central battery power pack 30 is connected to the self-contained emergency lighting module 10 at the connection point normally provided for the local battery 14.

An important feature of the central battery power pack 30 is that it must be able to accept the usual charging current reserved for the local battery, which in this embodiment is not present. The central battery power pack is designed to accept this charge current without damage. The flow of charge current is indicated by a lit charging LED 32 from the emergency lighting module 10.

This lit LED 32 is to show that the system is connected and ready for work.

If the central battery supply 24 is disconnected from the central battery power pack 30, then the charge current is inhibited and the LED 32 goes out.

When the unswitched mains power supply 12 is removed (during a test or a power cut), then the self-contained emergency lighting module 10 disconnects the lamp 16 from the normal mains ballast 18 and connects it to an internal emergency inverter (not shown) . The inverter is powered from the central battery 24 via the central battery power pack 30 and the lamp 16 continues to operate, so long as the supply from the central battery system is maintained.

Thus, the power pack 30 connects to the central battery 24 for power and connects to the self-contained emergency lighting module 10 via the battery connection that is normally used for a battery 14.

The central battery power pack 30 is designed to operate from either llOV AC, llOV DC, or 230V AC, these being the most popular system voltages. Of course other voltages could be used.

The arrangement shown in Figure 3 provides an output voltage that mimics the self-contained battery 14 shown in Figure 1 and, so as to allow the widest application, the output voltage is selectable for 3, 4, 5 and 6 cells, that is 3.GV, 4.8V, 6V and 7.2V nominal.

The advantages of the self-contained emergency lighting module 10 when used in relation to the central battery power pack 30 are that one module can be used for both central battery systems and local battery systems. The same central battery power pack 30 can be used for all systems. The input voltage range covers all popular central battery system voltages. Also, output voltages are selectable for all popular self-contained battery voltages. The self-contained module charge current is used to monitor the central battery unit system voltage.

Output current from the central battery power pack 10 is sufficient to start and run all popular self-contained emergency lighting modules 10. This current is typically 1A continuous and 4A surge for four seconds with a voltage drop of less than 0.5V.

The system described above allows the advantages of the high volume production of self-contained emergency lighting modules to be used, in addition to the advantages of the central battery systems. Also, there are space saving issues which advantageously arise from the removal of the need for a local battery 16 and the replacement thereof with the central battery power pack 30, which is both smaller and lighter than the local battery 14.

In addition to the power pack being used with a self- contained emergency lighting module it can of course be used to convert a self-contained emergency luminaire into a central battery emergency luminaire.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings) , and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s) . The invention extends to any novel one, or any novel combination, of the features

disclosed in this specification (including any

accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

CLAIMS: 1. A power module for a self-contained emergency lighting module,

which power module comprises: a charging current receiving element, operable to receive a battery-charging current from an attached selfcontained emergency lighting module; a central supply receiving element operable to receive power from a centralised battery power supply; the power module being operable in an emergency condition to supply power from the centralised battery supply to the attached self-contained emergency lighting module.
2. A power module as claimed in claim 1, which is operable to accept and dissipate a battery-charging current by means of the charging current receiving element.
3. A power module as claimed in claim 2, where the charging current receiving element is operable only when the central supply is connected.
4. A power module as claimed in claim 2 or claim 3, in which the charge current receiving element is inhibited when the centralised battery supply is disconnected or falls outside a rated range.
5. A power module as claimed in any preceding claim, which mimics a power supply from a local battery that is expected by the self-contained emergency lighting module, whereas the power supply is in fact provided to the power module by the centralised battery power supply.
6. A power module as claimed in any preceding claim, which is more compact than a local battery that it replaces.
7. A power module as claimed in any preceding claim, which incorporates output selection means operable to be switched to select an output voltage of the module.
8. A power module as claimed in any preceding claim, which incorporates input selection means,
9. A power module as claimed in claim 8, in which the input selection means are operable to select an input current mode.
10. A power module as claimed in claim 8 or claim 9, in which the input selection means are operable to select an input voltage.
11. A conversion kit for providing emergency lighting, the conversion kit comprising: a self-contained emergency lighting module; and a power module comprising a charging current receiving element, operable to receive a battery-charging current from an attached self-contained emergency lighting module; a central supply receiving element operable to receive power from a centralised battery power supply; the power module being operable in an emergency condition to supply power from the centralised battery supply to the attached self-contained emergency lighting module.
12. An emergency lighting system incorporating at least one power module as claimed in any one of claims 1 to 10, at least one self-contained emergency lighting module and at least one lamp.
13. An emergency lighting system as claimed in claim 12, which incorporates a lamp ballast for each lamp.
14. A power module substantially as described herein with reference to Figure 3 of the accompanying drawings.
15. An emergency lighting system substantially as described herein with reference to Figure 3 of the accompanying drawings.