Escalator & Elevator Problems

Hope you've taken on board the lessons from the Kings Cross Underground Fire investigation.

Escalator fires are not rare. We remember this one in particular because of the fatalities. These fires are the result of the combustable environment of oils, greases, rags, and trash. Code requires regular cleaning here in America, however lax inspections coupled with the profit generated from reduction in maintenance labor allows this to happen. Joe

We were contracted to do the load test for a standby generator in a newly constructed building. After confirmation of output, we marked the output for phase sequence as it had not been connected to the ATS at that time.

Later, the elevator contractor blamed us for causing damage to the the elevator equipment due to incorrect phase rotation. This accusation was dropped after brief litigation.

To this day, I still wonder how this damage was possible, considering the attention normally given to new installations of motor driven equipment.

Depending on elevator equipment age and type: most have phase rotation and balance monitors that protect the equipment very well. Joe

I should have mentioned that over the past few years as we performed elevator inspections and safety test (we are a licensed State of Florida inspection firm) we've found several 3-Phase monitors disabled and the circuitry jumpered. One robust device used for years had a center axle with three coils surrounding the a rotating fixture; when phase was correct, the axle spun about 90 degree's and glass enveloped mercury glob would flow and short across two conductors and pass the signal to the controller that all was good with incoming power. We know there are still thousands of these devices still inservice in the U.S. and we have a couple here in our lab for fooling with, or just because their cool. Joe

Hi

Here at THC controls we make regeneration units for elevators, so that each time the elevator goes down, it generate power to off-set the building total power consumption.

If you're interested drop me a line

Wouldn't you mean when the empty or lightly loaded traction elevator goes up? I believe a hydro can be made to generate some power in the down by the moving mass forcing a driven component. Not sure how efficient that would be tho. I worked on the traction elevator re-gen systems in the 1980's. I recall a study done in late 80's that claimed so little was gained overall that the systems in use then had little practical applications. So the majority of the industry here just took that energy and dissipated it via resistor banks or other circuitry. Late 90's: while employed as an engineer for a major elevator manufacturer, I traveled throughout the states disabling re-gen software and using resistor's to waste the energy. A couple of my major clients won't consider any re-gen or "green" initiative unless recapture is within 3 years from investment. Joe

Hi Joe

we have designed units to generate power from falling weight, so when the car goes down, and instead of the resistors, they are replaced with the re-gen unit.

Is it efficient?

Yes... the application we have used for R&D in Canada, is for pump jacks, and the units have cut power consumption by 30-40%

The older re-gen units were VERY costly and VERY inefficient as teh technology used in the 80's was not as good as it is today.

The ideal application is to off-set power consumed by the building and in addition with tha harmonic mitigation of the re-gen drive the power savings add up. Larger units can feed directly back to the grid and with an export meter, the user will get paid for exported power.

Thank you for the info. I'll have to look further into the re-gen possibilities such as application and cost. Joe

My problems were in modifying the structures in railroad stations to accommodate the "new" standard of three flat steps top and bottom for transport facilities. Sixteen inches at each end doesn't sound like much but it leads to a lot of demo and rebuild. I thought it stupid since the originals had functioned well for twenty five years or so, the new standard should have been reserved for new facilities.

That 16" can be an difficult item to get into a existing structure and maintain the U.S. 30 degrees of the unit. Building has to be altered. Three step egress and exit is easier on the riding public but has economic limitations. Your deal must have been for replacing the entire existing escalator with new units? We do not often make that recommendation to our clients; we've found it's better all the way around to make right what's already in place. Lesser overall cost and the end product will out perform the newer stuff if the project is designed correctly. Or we draft a variance request to use two level step units due to high alteration cost. Joe

In each case, the client was a nominally independent authority set up by state government(s), they insisted that we met the standards of the day, they wanted their butts covered. I understated the ages, some were thirty years old and some were older. The odd thing was that in some places, we we cut into an already short, step-off zone and that was okay.

Often consultants and/or code authorities require compliance with the most stringent code in effect. That is a very good "butt cover" as you mentioned. Escalator age is much like I believe it is with some people; it's not the age, it's the mileage. I have personally taken care of two 1936 escalators that operate smooth, reliable and most importantly; safely every day. Interesting aside; access is through a portal in the floor a few feet away and then overhead clearance to the large drive machine is 54". Full control board, geared elevator machine with a chain sprocket in place of the normal rope sheave. Parts can be problem but we haven't had anything we couldn't get or make. All code compliant. One determining factor consultants often use is: who is able and has the knowledge to take care of the older stuff as senior technicians retire? This has been a major concern in the elevator industry for many years as there is little in the way of practical education going on. Thank you for contributing. Please stay in contact. Joe