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A dc motor would work, an ac motor would be cheaper if you can run at a fixed speed, something like a paravalux geared motor is what I'd be looking for, if you want variable speed then the cost of a variable speed ac drive would probably make an ac motor prohibitive a dc motor speed control is easy to make and cheap, or a universal motor for that matter.
You could use a standard motor starter to do the trick, pull one of the wires off the stop button and then wire it in series with the normally closed contact of a button actuated limit switch, run an arm with a rubebr roller on the end (to protect damaging the wire) to make contact with the wire (and trigger the switch) when one reel is full and another switch for when the other reel is empty, connect both of the swtich contacts in series so whene one of them is actuated is has the same effect as pressing the stop button on the starter.
Another way is to get hold of a turns counter with a preset contact, you preset the no. of turns and the contact operates at that no.
You dont need a micrcontroller for this.
The wire I'm dealing with is high carbon wire - tensile strength of 2050 - 2250MPa
I have a moment of inertia of 500kgm2
I am confident that the wire will be strong enough to withstand the strain of turning a 500 spool of wire which is placed on thrust bearings
Thanks for your help
Right then I see your point your concerned about breaking the wire, the kind of system that monitors wire tension is more indepth and maybe you should think about a proprietry tension controller system.
A basic approach would be to spring load the 'dancing' arm I mentioned so that if the wire tension were to suddenly increase the arm would lift temporarily shutting off the drive, though this system isnt particularly accurate and resticts your winding speed.
Perhaps I was wrong with the kind of complexity you need maybe you do need a microcontroller this isnt a simple little winding jig.
Whats your competence level, can you program?, do you have any experience of load cells etc.
Those reals are heavy. I would also consider a dancing arm tension system.
One way is a brake on one side. The other problem is stopping the motor. They will usually overrun.
I designed a bidirectional synchonous AC motor tension system, but virtually no weight. Turned out we didn;t need it. I didn't take into account that when off, there is drag and you have to reverse the current on the brakes when dealing with low tensions.
I have zero experience with heavy machinery, so excuse me if the idea sounds ridiculous.
What about a load sensor measuring the weight of the whole bigger spool assembly? As the spool weight decreases the motor pulling force is progressively reduced.
As a result, the first meters of the spool are unwind with all the available force, and the last meters of cable are unwinded very slowly.
Just to refresh my point - I've meade one or two changes
I have two large wire spools. One empty and one full. The full spool (approx. 500kg) is much larger than the empty spool (100kg when full).
I wish to transfer the wire from the large spool to the smaller spools. I want to do this regularly so I want to set up a system that will not have to be monitored but can turn itself off when the smaller spool is full and/or the larger spool is almost empty - whichever happens first.
I want to keep this as simple as possible.
I'm looking to put a motor on the small spool and use this to turn the large spool through the pull of the wire
I will be using one small spool at a time along with one large spool at a time
I want the entire system to shut down once the small spool is full or the large spool is almost empty - whichever happens first
The wire in question is a high carbon wire with a very high tensile strength so this should not be a problem for the wire - I am confident hat the wire will be able to handle the pull as long as there is a slow start up and slow down
The large spool has a weight of 1100lbs (500kg), a diameter of 28 inches (70cm) and a depth of 12 inches (30cm) - in the picture attached there are two large spools stacked on top of eachother on one pallet
The small spool has a diameter of 19 inches (48cm) and a depth of 9 inches (24cm)
I want to unwind the entire contents of the large spool onto 5 smaller spools - each smaller spool will be manually lifted off and replaced with an empty spool each time the small spool is full - maximum rotational weight on the take up spool at any one time is 220lbs (100kg)
I would like to start and stop the small spool slowly - ideally a slow start/stop lasting approximately 3 to 4 seconds
I would like to turn the small spool - the one powered by a motor at between 3 to 5 revolutions per second (180 to 300 rev per minuet)
A uniform wrapping speed is not critical - I am conscious that the wrapping speed will change as the diamter of the larger spool decreases and the diameter of the smaller spool will increase. I don't need any footage count - just plain transfer from one spool to another
I do not have any motors at the moment so any suggestions would be greatly appreciated
I have access to 110 Volt, 230 Volt and 3 phase 400 Volt supply
I don't need the motors to run in reverse just in one direction
I'm hoping to get this done for as cheap as possible - at most €1500
Please give me some suggestions on how to start and stop both motors and the best type of motors for the job
You might look into using a strain gauge to weigh the smaller spool as it winds up and shuts off at a specific weight and have a brake on the larger spool to keep the tension and to stop the smaller after the specific weight is achieved. The brake on the large spool could be as simple as an aluminum disk that easily attaches to the spool and some magnets on a bar that doesn't rotate.
Your procedure would be something like this, attach the aluminum disk/magnet bar to larger spool and place on shaft, string wire to small spool, start motor, when the weight reaches setting, motor shuts off and coasts to a stop, cut wire, replace small spool, start motor, repeat, secondary sensor senses that the large spool is not turning, empty, and shuts off motor.
The strain gauge doesn't even have to "weigh" the wire, the output is amplified and compared to a set point, either of which can be adjusted to get the results you want.
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