28 replies to this topic

[Lift Kid]

The multi-colored buttons are part of the code, from what the L-P guys told me. I guess they put the E-stop guard on so the lifty's can't put their feet up on the desk, or lean on the pedestal and set the E-brake!

[liftmech]

New code lays out colours and styles of buttons. Normal stops are now the big red mushroom, which used to be the E-stop. E-stops are guarded to prevent inadvertent used of the e-stop (it takes longer to stop the lift than the normal stop and is harder on the equipment). Start is green, fast is black, medium is blue, slow is yellow. All other buttons are at the owner's discretion but cannot be any of the above colours- we use orange for the tower test, grey for reset and white for the signal. I didn't know Poma put meduim speed on their lifts, but I'm sure it's not that difficult to program in.

[chasl]

liftmech, on Aug 18 2007, 09:10 AM, said:

New code lays out colours and styles of buttons. Normal stops are now the big red mushroom, which used to be the E-stop. E-stops are guarded to prevent inadvertent used of the e-stop (it takes longer to stop the lift than the normal stop and is harder on the equipment). Start is green, fast is black, medium is blue, slow is yellow. All other buttons are at the owner's discretion but cannot be any of the above colours- we use orange for the tower test, grey for reset and white for the signal. I didn't know Poma put meduim speed on their lifts, but I'm sure it's not that difficult to program in.

(it takes longer to stop the lift than the normal stop and is harder on the equipment)

While I do not have a code book in front of me, I am not sure that this statement is correct.
While I agree it is harder on the equipment, I do believe that with an empty lift, an emergency stop should be slightly quicker than a normal stop. I do not remember the code reference for the stoppping distance at this time.
And at 53 years old I reserve the right to be incorrect.

[LuvPow]

I agree Chasl... it has been my experience working at each resort, that every lift I have stopped with the E-Stop does stop faster..yes, it is harder on the Equip....but if it prevents a guest from being injured I certainly won't hesitate to use it. I know J. Mauch in Co. is really pushing to have the E-stop enclosed almost to prevent it's use...and from a Maint. aspect I can see the issue...but Operations may have a different point of view...sometimes its that extra couple of seconds that can make a difference regarding an injury.

[Kicking Horse]

LuvPow, on Aug 18 2007, 10:27 AM, said:

that every lift I have stopped with the E-Stop does stop faster

Estop does not stop the lift faster or at least the lifts that I have ran. All the lifts that have operated take 200 to 500ft to stop when a estop is pushed.

[chasl]

Kicking Horse, on Aug 18 2007, 11:41 AM, said:

Estop does not stop the lift faster or at least the lifts that I have ran. All the lifts that have operated take 200 to 500ft to stop when a estop is pushed.

I am sorry, But I think those numbers are totally off the mark, 200 - 300 for a HSQ might be close but 500ft seems awfully long.
regardless I still believe code mandates a shorter stopping distance for an e-stop. For sure you will have a longer stopping distance for the HSQ than a fixed grip lift, I hope you are not stating that these numbers you are talking about include stopping distances for a 2,3,4 pass. fixed grip lift.

[vons]

4 out of 5 detachable lifts at Copper have longer E-stop distances. The only HSQ with a shorter E-stop is T-rex and at full speed it is quite an experience on a chair, the line bounce is intense. The E-stop’s main difference is that it disconnects the power and acts directly on the drive sheave, it is therefore only to be used when you have lost control of the lift and other stops do not function properly it does not need to necessarily stop the lift any faster it just needs to be fail safe stop. I could not tell you code on this but it has been this way since 02’ when I started a Copper

[lastchair_44]

Our e-stops on our Gondola take just a bit longer than a normal stop. I was under the impression that a normal stop which uses the electric motors to brake was quicker just because it is a more controlled stop. The code can't specify a standard stopping distance for all lifts can it? Wouldn't profile, length, weight of carriers etc. come into play on the stopping distances? I think there is a criteria for stopping distance because when we did our acceptance test after the capacity upgrade we had to tighten up our bullwheel brakes to make the acceptance test. For some reason I remember 80 or 90 ft. being the limit on our e brake stopping distance. 200 to 300 feet seems ridiculously long...maybe on a decel supervision test stop? But even that seems high to me. I do think the older Doppelmayrs liked to have a shorter E stop than normal stop distance though.

[Lift Kid]

liftmech, on Aug 18 2007, 09:10 AM, said:

I didn't know Poma put meduim speed on their lifts, but I'm sure it's not that difficult to program in.

That was actually a special request from Vail. 10 and 14 are the only lifts with medium buttons being built by Poma this year. Vail, apparently, didn't want the ops to have to learn that there is no Medium on a Poma!

[vons]

Their ops may just like a medium speed option, there have been times I have wished our poma detachable lifts had a medium speed I have found it very useful on T-rex because slow is a crawl where as the med takes just enough off to help.

[liftmech]

chasl, on Aug 18 2007, 09:33 AM, said:

(it takes longer to stop the lift than the normal stop and is harder on the equipment)

While I do not have a code book in front of me, I am not sure that this statement is correct.
While I agree it is harder on the equipment, I do believe that with an empty lift, an emergency stop should be slightly quicker than a normal stop. I do not remember the code reference for the stoppping distance at this time.
And at 53 years old I reserve the right to be incorrect.

Vons did clarify my statement, our fixed-grips do stop faster on an E-stop. Some are smoother, but many are quite violent due to the not-quite true bullwheel flanges on older lifts.

[skier691]

Button covers for the 'E-Shutdown' (I believe thats the termology now), what a great problem solver. On our CTEC FG quads, the standard stop is slightly shorter and/or unnoticably different, and yes, the brakes are properly adjusted and they torque out. I would believe that it depends on the lift, and brake type. For example, set a e-sd button on our '67ish riblet double, the brake you activate is the wooden bullwheel band brake. On a warm day, the oil is flowing nicely, so you achive faster brake activation, but is it faster than the service brake?? UMMMM? fridge run, out

[chasl]

I have not been able to find the new code, But I will stand corrected, I think,
I found on the web a copy of the NY code which has adopted the ANSI standard
In it they state that the
Service brake - must be designed to decelerate the lift to a stop at a rate of 2.0 ft(0.61m) / second squared.
Drive sheave brake – Must be designed to decelerate the lift to a stop at a rate of 1.5 (0.46m) / second squared.
It does go on and gives other parameters but that is main focus.

I did not find a minimum distance

I actually did not find or did not look far enough for anything mentioning regenerative braking.
In that ANSI only mentions the rate for a maximum stopping distance, I see no reason that if you want your normal stop quicker than this so be it.

I am thinking that 300 - 500 feet is to much, just do the math for your system

I did find that in New Zealand code states that the rate must meet a
Minimum - of 0.45m / second sq.
Maximum – of 2.0m / second sq.
Furthermore in no case shall the rate be greater than the distance between carriers.

This post has been edited by chasl: 19 August 2007 - 12:07 AM

[Allan]

chasl, on Aug 19 2007, 12:14 AM, said:

I have not been able to find the new code, But I will stand corrected, I think,
I found on the web a copy of the NY code which has adopted the ANSI standard
In it they state that the
Service brake - must be designed to decelerate the lift to a stop at a rate of 2.0 ft(0.61m) / second squared.
Drive sheave brake – Must be designed to decelerate the lift to a stop at a rate of 1.5 (0.46m) / second squared.
It does go on and gives other parameters but that is main focus.

I did not find a minimum distance

I actually did not find or did not look far enough for anything mentioning regenerative braking.
In that ANSI only mentions the rate for a maximum stopping distance, I see no reason that if you want your normal stop quicker than this so be it.

I am thinking that 300 - 500 feet is to much, just do the math for your system

I did find that in New Zealand code states that the rate must meet a
Minimum - of 0.45m / second sq.
Maximum – of 2.0m / second sq.
Furthermore in no case shall the rate be greater than the distance between carriers.

Canadian code says this and it applies to the service and bullwheel brakes:

Stopping Times and Distances for Circulating Passenger Ropeways (See Clause 5.6.1.)
Note: This Appendix is not a mandatory part of this Standard.
Stopping time (t)
t = v/a
where
t = stopping time, s
v = velocity, m/s
a = rate of deceleration, m/s2
Stopping distance (s)
s = v2/2a (Velocity squared, divided by 2 x the rate of decel)
where
s = stopping distance, m
v = velocity, m/s
a = rate of deceleration, m/s2
The following table shows allowable stopping times and distances for the maximum allowable rate of
deceleration of 1.5 m/s2 and the minimum rate of 0.45 m/s2. Clause 5.6.3 specifies that the braking
distance shall not be greater than the distance between carriers.

[Emax]

Allan, on Aug 19 2007, 09:39 AM, said:

Canadian code says this and it applies to the service and bullwheel brakes:

Stopping Times and Distances for Circulating Passenger Ropeways (See Clause 5.6.1.)
Note: This Appendix is not a mandatory part of this Standard.
Stopping time (t)
t = v/a
where
t = stopping time, s
v = velocity, m/s
a = rate of deceleration, m/s2
Stopping distance (s)
s = v2/2a (Velocity squared, divided by 2 x the rate of decel)
where
s = stopping distance, m
v = velocity, m/s
a = rate of deceleration, m/s2
The following table shows allowable stopping times and distances for the maximum allowable rate of
deceleration of 1.5 m/s2 and the minimum rate of 0.45 m/s2. Clause 5.6.3 specifies that the braking
distance shall not be greater than the distance between carriers.

Very well defined, completely reasonable.
"Stripeside" should adopt this section verbatim.

This post has been edited by Emax: 19 August 2007 - 08:14 AM

[shoemaniii]

braking requirements is an interesting topic. as noted above, all lifts are different, therefore braking systems are required to absorb differing amounts of energy for each particular lift. the rulemaking process for braking systems thus contains averages, minimums, maximums but not many specifics.

some general notes;
-- without a regen drive, normal stop and emergency shutdown stop distances/times will vary somewhat with load
-- with a regen drive, normal stop distances/times will remain the same regardless of load, e-shutdown distances/times will still vary
-- b77.1-2006 now specifies, via a chart, minimum and maximum stop distances. data given is based on minimum and maximum rates of deceleration (1fps sq to 5 fps sq)
-- the CAN code quoted has the same rates of decel as the US, but is only a guide and not mandatory.
-- the e-shutdown distance on detachables must be less than carrier spacing, to prevent carrier collision is the terminals.
bobp

[Lelec]

shoemaniii, on Aug 21 2007, 07:04 AM, said:

braking requirements is an interesting topic. as noted above, all lifts are different, therefore braking systems are required to absorb differing amounts of energy for each particular lift. the rulemaking process for braking systems thus contains averages, minimums, maximums but not many specifics.

some general notes;
-- without a regen drive, normal stop and emergency shutdown stop distances/times will vary somewhat with load
-- with a regen drive, normal stop distances/times will remain the same regardless of load, e-shutdown distances/times will still vary
-- b77.1-2006 now specifies, via a chart, minimum and maximum stop distances. data given is based on minimum and maximum rates of deceleration (1fps sq to 5 fps sq)
-- the CAN code quoted has the same rates of decel as the US, but is only a guide and not mandatory.
-- the e-shutdown distance on detachables must be less than carrier spacing, to prevent carrier collision is the terminals.
bobp

I would add one general item and one item for detachables:
- Limits on deceleration rates for the ANSI B77.1 2006 are based on measurements taken over 1 second. Since it typically take several times this amount of time to complete a stop (say 4-8 seconds) it is possible to violate this requirement without violating the average deceleration range of 1.0 - 5.0 ft/s^2 for the entire stop or the stopping distance requirements that result from assuming a perfectly linear deceleration rate....beware the chart recorder. I have seen stops that looked beautiful and smooth as ice but did not pass this requirement because of momentary excessive deceleration when the pads first make contact with the braking surface. While I understand some of the reasons for the one second interval this can be a frustrating process.
- For detachables mind the distance between the device(s) detecting improper grip attachment at the top terminal and the breakover point at the top tower. An emergency stop must bring the lift to a standstill in less than this distance because otherwise an improper grip attachment (typically an emergency stop) could get ugly. This bites me in the butt way more often than carrier spacing considerations do.

And on that note there is an earlier post regarding 300-500 foot stops (!!!!) - is someone using a new unit of measure (decifeet maybe?) and forgetting to change the text? Typical emergency stopping distances that I have seen for detachable emergency stops with properly adjusted brakes range from 40-80 feet from 1000 fpm and using the formulas from ANSI B77.1 2006 gives an acceptable range of 28 to 138 feet from 1000 fpm.

[shoemaniii]

good point on the 1sec interval. smoothly removing the energy during an e-stop (no regen) from these large systems seems impossilbe when we use fixed flow controls on our brake dump lines. we need smarter e-brakes, that self-adjust according to speed/load conditions.

adjusting for satisfactory e-stop distances for 100% loaded uphill and 100% loaded downhill is crazy-hard.

the requirement for a device that monitors correct grip attachment and shuts the lift down if incorrectly attached, is for loaded carriers only - no? 3.1.4.3.4.3

i'm aware of more than a few detaches with not enough flat rope at the top station/departure side and therefore speed is reduced for downloading passengers.
bobp

[Lelec]

shoemaniii, on Aug 30 2007, 04:44 PM, said:

good point on the 1sec interval. smoothly removing the energy during an e-stop (no regen) from these large systems seems impossilbe when we use fixed flow controls on our brake dump lines. we need smarter e-brakes, that self-adjust according to speed/load conditions.

adjusting for satisfactory e-stop distances for 100% loaded uphill and 100% loaded downhill is crazy-hard.

the requirement for a device that monitors correct grip attachment and shuts the lift down if incorrectly attached, is for loaded carriers only - no? 3.1.4.3.4.3

i'm aware of more than a few detaches with not enough flat rope at the top station/departure side and therefore speed is reduced for downloading passengers.
bobp

Yep the requirement is only for downloaders but unfortunately we have always assumed a minimum of 10% downhill loading for maintenance personnel and therefore have to meet this stopping distance requirement on all lifts. Come to think of it I will check if this is a standards issue or if it is just our salesmen have always sold it this way because it is a pain in the butt having to deal with it on lifts that you know will never have a downloader.

I agree that "smarter" E-Brake systems are also needed. In the really difficult cases (steep lifts with large downhill loading capacities), even if you can get it "just right" so that it passes uphill and downhill stopping requirements during acceptance testing, what are the chances that the maintenance crew is going to be able to maintain that fine balance over time, equipment wear, temperature fluctuations etc.? We are working on systems that modulate the solenoid valve for the emergency brake so that the application of the brake can be "ramped" to full braking force (similar to modulated service brakes). Because there are no accumulators etc for these brakes however you pretty much get one chance to set the ramp rate because, once bled off, the pressure cannot be restored quickly. You therefore need to know what the driving torque is at the moment a call is made to the brake (i.e. downhill loads will lessen or even reverse the driving torque requirements and uphill loads will increase it). This data is fairly easy to get when operating with an electric drive but is a different animal when operating with an auxilliary diesel.

Alternatively, we could just increase the rotational inertia (flywheels on the high speed input etc) of the system such that the loading component (uphill or downhill) is a much smaller percentage of the energy that must be removed by the brake. The braking force can then be set very high while meeting uphill and downhill stopping requirements. Being an electrical type I strongly support the latter approach .