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- Duty cycle and the CMAA
is the amount of time that a crane is being used
within a given time period.
So CMA typically looks at things based on hours of use.
So, if you are trying to determine what duty cycle
you need for your application,
you need to look at the capacity,
you need to look at the percentage of capacity
that that crane is lifting each hour.
You also need to look at the number of lifts per hour,
and how many times that crane's being used.
So basically what that does is you need to look,
determines your number of motor start-stops
and then also will, that'll help you determine
what duty cycle your crane is going to be used for.
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So an end user needs to provide that information
for the sales personnel,
and also for engineering.
Because what that does is,
gives us a snapshot of what your application is
so that we can determine what componentry to use
on your overhead crane.
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So when classifying a crane,
it's not really based on price point.
What you need to do is look at maintenance
and how much down time affects your production.
If you are looking at an application
where you're using this crane on a regular basis,
every hour, multiple shifts per day,
down time is really probably going to be an issue for you.
So, you need to look at the application,
and then duty cycle,
because you don't want a crane
that's going to be cutting out on you on a regular basis.
You need to look at the efficiency,
and what that's going to do for your production.
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If you buy the wrong equipment,
what that's gonna do is hurt you on the backend.
So you need to make sure that the componentry
is going to stand up to the time and rigorous use,
that is going to be going through,
because the crane is going to be vital to your production.
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So Class A crane, is infrequent use and maintenance.
So, you typically see these in,
let's say a steel mill as a maintenance crane.
It's used to lift parts up
for the main process cranes as they go down.
Also, you would see this used as a stand-by crane.
So if a main crane goes down,
you can move this crane in to perform lifts
while the other one is getting fixed.
A Class B crane is light service.
You see this lifting maybe one or two times a day.
You're not seeing it used over and over,
are typically used in a work station environment.
A Class C crane is more moderate use.
You see that in a typical fab environment,
our crane shop for example.
You're really using them throughout the day
on a more normal basis,
but it's not seeing an over abundance of lifts
or higher capacity lifts.
So a Class D crane is more of a heavy service,
heavy fabrication, you start to move into
more componentry is designed based on lower maintenance.
You start to see higher capacity lifts
beyond you know 50% of the capacity of the crane.
More start-stops per hour
where you're doing more lifts as well.
So Class E cranes are more severe service.
These are ones that are vital to production.
If this crane goes down,
your production is down and then you're losing money.
So, those types of cranes
are used in more of an auto industry.
You see those in steel mills.
Again, more high production, higher output applications.
So Class F crane is a severe service.
You see these in steels mills,
hot metal cranes that are constantly being used
for lifting materials, moving materials,
and then going back, performing the next lift
and continuing to go through the application.
So, these are constantly going.
Typically, you'll have a back up crane
of equal service ready to be used
in case this one goes down.
If this is down, an entire plant shuts down.
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So, when you move from a more modular type crane
to a process crane,
the things that you start to see changing
or affecting your price is the hoist, the end trucks,
and then the controls.
You start to see larger motors, different bearings,
and what those allow for is less maintenance.
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