Elevator accelerationgreenspun.com : LUSENET : Elevator Problem Discussion : One Thread
I was wondering what's the "standard" and maximum acceleration for an elevator, and which norms are available online. Thanks,
-- Giselle (firstname.lastname@example.org), April 28, 2004
Acceleraton and Jerk (rate of change of acceleration) are human comfort considerations. Practical limits are 4 ft/sec^2 acceleration and 8 ft/sec^3 for jerk. These are fairly aggressive but acceptable. Beyond these levels the car becomes an amusement ride. Use about 70% of these levels for a very smooth feel.
-- Don Vollrath (email@example.com), April 28, 2004.
Thanks ! Any idea how this compares to a passenger car and passenger plane acceleration (under norma circunstances, not crash !) ?
-- Giselle (firstname.lastname@example.org), April 28, 2004.
It really depends on the engineering of the job. Generally, you use a slower accelleration rate on a geared car as opposed to a gearless. Personally, I use a simple method that is easy to figure out looking at a storage scope pattern. Usually 120-140 FPM/Second is nice on a geared, while 220-240 FPM/Second works out nice for a gearless. I use it this way because all you have to do is count the graticules on the scope from stop to full speed. For the numbers folks, 140 FPM/Second is 140/60=2.33 foot per second per second. The important thing to consider is the engineering done on the job with regards to traction limits, drive/power limits, as well as variable loads and their effects with regards to inertia, harmonics, etc. No matter how you try, you're not going to get a volkswagen to do 210 MPH in the 1/4 mile.
An excellent resource is to ask Don Vollrath over at Magnetek drives. He's probably the "Shell answer man" when it comes to what you can actually do with what you've got. Cheers!
-- Steve (email@example.com), April 28, 2004.
The 4 feet per sec per sec., accelearation was decided on by accidents to pregrent women.
-- Tom Grosch (firstname.lastname@example.org), September 12, 2004.
difficult to compare car or plane acceleration to lifts as one is horizontal and the other is vertical, and rapid acceleration vertically down can lead to a very bad case of queasiness,also the deceleration can be uncomfortable for the elderly if it is too harsh Roughly, a lift speed of 200 ft/min is 1 metre/sec this works out at only 3.6 kilometres per hour or 2 and a quarter miles per hour. (to convert kilometres to miles multiply by 0.6214)so your high speed lift may only be doing 10 miles per hour That, incidentally, is about the same speed as I manage on my drive home some nights
-- geoff judge (email@example.com), September 13, 2004.
all the above is bullshit....the only acceleration is the one you can actually feel...not measure with some damn tool....if it breaks your legs going up, or you hit the ceiling going down, its too fast.......but I suppose it keeps consultants in a job.
-- dayle (firstname.lastname@example.org), September 14, 2004.
What Dayle says is true if it feels right it is right and I'm sure we have had this before and with the same outcome
-- geoff judge (email@example.com), September 14, 2004.
there isn't a thing in the code that states you can't knock people down or knock people off their feet. it's all done to the way the adjuster is used to setting them up. no two adjuster's set the same.
-- (firstname.lastname@example.org), September 14, 2004.
While it is true that what you feel is what counts, it is also true that what one feels is an individual judgement. What you feel is overly fast (or slow), I might feel is just fine.
Instrumentation makes it possible to make measurements that produce QUANTITATIVE values, as opposed to subjective judgements.
Consultants (good ones at least) assign generally accepted quantitative values. Otherwise, it becomes a debate - the elevator installer says it's fine, the consultant thinks not.
Also, what if the performance meets the specified values, but the owner still doesn't like it? Now, the consultant must support the installer if the specified criteria are met.
With all due respect, in this day and time, there is no reason to use seat of the pants methods when accurate quantitative figures are easily obtainable.
-- John Brannon (email@example.com), September 14, 2004.
we seem to have gone away from the original question here! However, there are some things that need saying though. 1. It is no use a consultant setting parameters for say a Kone Lift or a Thyssen lift as all these parameters were done in the R&D stage. 2. Most installers set the lift up according to the manuals and ,in theory at least, the ride parameters set on site will be similar to those in the specification drawn up by the consultant as we are all trying to get the same result which is passenger comfort. The original question was if there are any "standard" and the answer is that it depends upon the lift ,the consultant, the tester, the installer and after all that, the building owner or custodian. Not forgetting that the service guy will adjust things as soon as he gets on site.
-- geoff judge (firstname.lastname@example.org), September 15, 2004.
in a perfect world, what your saying is correct, BUT, how many times have we saw " capitol omissions " during a construction phase where the cost overruns make them cut a few elevators out, or only half a mod performed. the people paying the bills for all of this want to see their elevators moving people and don't care about the ride.
-- (email@example.com), September 15, 2004.
It's all in the numbers, guys. One "G" for (gravity) is about 32 ft/sec/sec. One G going up will cause your 'weight' to double. One G going down you will be 'weightless'. Fun on roller coasters but not very acceptable to passenger elevators. Practical limits are about 1/8 that value or 4 ft/sec/sec for vertical elevators and also horizontal movement (trains, planes, busses) where someone may be standing. Belive me...You will have complaints if accel and decel rates are set up faster than that.
During take-off and landing of good jet airliner, horizontal acceleration (pilot in a hurry) and decel (hard wheel braking) may be nearly 1/2 G. That's why there are supposedly no loose objects and seat belts.
If you have access to one of them thar PMT recorders, turn it ON once to see what your Chevy SS can do!
-- Don Vollrath (firstname.lastname@example.org), September 15, 2004.