Emergency Evacuation Posts

Power Systems International Welcomes Positive Feedback for Black Box ELPS

Power Systems International Welcomes Positive Feedback for Black Box ELPS

Jon Hill, Managing director of the company said “we have taken note of customer feedback about features the market and prospective users wanted to have on future emergency power systems for evacuation lift duty”.

“The new series 3 ELPS product announced by Power Systems International Limited is simply a “Black Box” point of use power system and features two internal and one external power circuits to feed a VVVF lift hoisting system or the starting device on a pump motor and electrics of a hydraulic lift”.

Point of use means the “black box ELPS” can be sited as close as possible to the lift traction or hoisting system and installed in a well ventilated indoors location. Installation is simple and being able to install the ELPS close to the point of use, the cable runs will be short and less exposed to the risk of copper thieves, vandalism or terrorist sabotage. These risks are prevalent where “centralised” back-up power systems are located remotely from the point of intended use.

About the Product:

“Black Box ELPS series 3” evacuation lift power system…

ELPS Series 2.jpg

The ELPS should be considered as a simple “Black Box” point of use back up power system for use with evacuation lifts and should be installed as close as convenient to the lift traction system and controller. The ELPS is supplied with a length of flexible cable for its input and a second cable for the output. One of the cables fitted with a CEE17 plug, the other cable is terminated with a CEE17 socket.

The package provided with the ELPS is a wall mounting steel “manual bypass box” for installation by the electrical contractor. This box is fitted with the mating plug and socket into which the flexible input and output cables of the ELPS are to be inserted.

This wall mounting box is also provided with a manual change-over bypass switch. When the switch is in the bypass position the mains power supply feeds directly to the lift traction system.

When the bypass switch is in the normal position, the mains power is then feeding the ELPS input and battery charger, the ELPS inverter output circuit is connected into the lift traction system.

In the normal mode of operation, the internal rectifier within the ELPS keeps the internal battery bank fully charged. The logic of the ELPS is energised whilst the key switch is in the ON position on the ELPS front panel. In this mode, the inverter is off and the mains power is fed through the internal static bypass circuit to the lift traction system.

ELPS sizes

The ELPS is available in three kVA sizes all with 400V three phase 50Hz input and output and will accommodate the load requirements of most passenger lifts of the VVVF traction hoist types or the hydraulic lifts with lift car weights up to 1600kg.

The intermittent operational duty cycle of a lift is difficult to quantify for determining the galvanically isolated PWM inverter and sizing the battery capacity of the ELPS product. How many landing stops and starts per hour, how many passengers in the lift car in the upward elevation and how many passengers in the lift car on the descending journey. The ELPS has to handle these variable loadings and interface correctly with the VVVF drive of the lift traction system or with the starting device on a pump motor of a hydraulic lift and to be able to perform its required evacuation duty of 10 upward journeys and 10 downward journeys over the required number of landings in 60 minutes.

How the ELPS works…

In order to comply with the current evacuation lift operational legislation we provide as part of our package a key operated remote control switch to be installed close to the normal lift call point on the safe refuge landing. The key switch is intended for manual intervention use by an authorised person to take manual control of the lift in an emergency situation.

IMG_0949 - Copy.JPGWhen the key is turned in the remote control panel, this is like the ignition switch of a motor car and turns on the inverter.

The starting of the inverter takes 1 second to produce full power output and sends a signal to the key switch to illuminate a ring LED to indicate “on emergency power”.

The electrical contractor will need to install a suitable 5 cores signal cable from the ELPS to the remote control point.

The lift manufacturer will also need to take this signal into the lift control panel for the lift operator to observe the “on emergency power” status alarm. Otherwise, there is the danger of an untrained operator or passenger continuing to use the lift unsupervised, ignoring alarms (as may persons often do) and become stranded when the  ELPS batteries are exhausted stopping the lift between floors.

This is one reason why some of the Local Authorities and Fire Officers object to allowing an automatic emergency power system and insist on authorised manual intervention for a person to take charge of operating a lift in the event if an emergency situation.

The ELPS can be provided with an optional automatic control feature that allows the inverter to start upon sensing the loss of mains power (or other source) at the input terminals of the ELPS. A signal will be provided to indicate the inverter is operating.

In order to comply with the current evacuation lift emergency operation legislation the ELPS will not deliver its output to the lift traction system until an authorised person takes control of the lift by using the “emergency use”  key switch fitted by the lift manufacturer on the control panel inside the lift car.

We can, on special request, provide an temporary over ride facility at the key operated remote control point to allow the ELPS inverter to start automatically and deliver power to the lift traction system controller without any manual intervention. However this configuration is unlikely to be accepted by the Fire Safety officers as a permanent facility.


The wall mounting dual purpose manual wrap around bypass box is as close as we can get to providing a “plug and play” simple and quick installation facility for connecting up the ELPS product to the mains power and to the lift traction system.

The box can be delivered ahead of the ELPS unit so the electrical contractor can complete the installation of the wall mounting box and fix all the cables without having the inconvenience of working around an in situ “black box” obstruction.








The package provided with the ELPS is the wall mounting steel “manual bypass and connector box” for installation by the electrical contractor. This box is fitted with the plug and sockets into which the flexible input and output cables of the ELPS are to be inserted.

Connecting the ELPS to the mains and to the lift

The ELPS will be delivered to site with the internal batteries fitted but with the DC isolator secured in the open position. Some site access and eventual position location conditions might require the ELPS batteries to be delivered separately and with the battery bank to be built into the ELPS on site.

With the ELPS placed in its final operating place with the battery bank internal connections correct, the plug and socket terminated flexible input and output cables stowed at the rear of the ELPS are plugged into the bypass box fitted on the wall.

When the bypass switch is in the normal position the mains power feeds the ELPS input and battery charger. The ELPS output circuit is connected to the lift traction system and controller.

The wall mounting box is also provided with a manual change-over bypass switch and when it is in the bypass position the mains power feeds directly to the lift traction system and controller thus bypassing the ELPS.

The emergency

There are many emergencies which may result in a building or part of a building needing to be evacuated. These emergencies are not just restricted to fire, earthquake tremors, explosion, a security threat, impact damage from crashing vehicle, flooding, storm damage, chemical, gas or other vapour release into the atmosphere.

The likelihood of one or more of these occurrences leading to an emergency call to evacuate will vary depending on the location and the use of the building. The majority of emergency considerations in the UK over the past 10 years have focussed on fire, toxic fumes and smoke emission and the exceptional storm water flooding and mains power line failures over the winter of 2013.

The familiar warning signage regarding not to use lifts in an emergency is often specifically about a fire emergency. At the discretion of official policy relating to Public Buildings it might be permitted to use an appropriate lift under supervision for the evacuation of disabled persons where it would be a slow and daunting task to use exit stairways for wheel chair bound persons.

The decision would have to be made based on the threat to life in using a suitable lift, possibly a lift that is a distance away from the reported emergency hazard area and where the risk is adjudged to be less than staying in the building or evacuating personnel into an unknown hazard.

The emergency alarm…

It is very likely a well designed BMS in a large building will have smoke detectors, Thermal monitors, probably Carbon Monoxide sensors and will probably have initiate a sprinkler system if a fire has been detected. It has to be assumed some level of automation will then alert the emergency services to respond.

Or, by a personal intervention using the benefit of the human brain power and the , sense to respond by pressing a “smash glass” fire alarm on seeing flame, detecting smoke and fumes and no doubt alerting the emergency services by phone.

Unfortunately the ELPS does not have the benefit of a human brain, it has a memory but must be “informed” about an emergency condition from a manual intervention or by an automatic signal from the BMS. The ELPS will, however detect a mains failure condition and energise its control logic in readiness for someone to command it to deliver power.

If the fire was in a substation or in a distribution board feeding power to the building and this initiated the remotely located standby diesel generator to take over from the substation Ring Main power supply. Should the cable to the building services distribution board for the lifts and lighting be damaged due to exposure to the fire there would be little point in having an emergency evacuation lift when there is no power available at the point where it is needed for the lift or the safe refuge landing lighting or for the smoke extract fans.

There is one obvious solution>>>>>

The ELPS point of use power product from the Power Systems International is the more secure and best cost effective means of providing power for emergency evacuation lifts

The ELPS “Black Box” delivers power when it is needed.

The ELPS “Black Box” delivers power to the exact point where it is needed