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Unread 03-05-2011, 01:11
wiiking123 wiiking123 is offline
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Re: 1 Victor 2 Window Motors

Note that these 2 window motors WILL be linked by the same shaft. Although, they will not be turning more than 60 degrees in either direction (the intended use was to be able to move an air cannon barrel up and down). If they are only moving 60 degrees, would I still have the high risk of twisting the shaft? If so, could it possibly be beneficial to simply use 1 window motor to move the shaft?
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Unread 03-05-2011, 01:58
EricVanWyk EricVanWyk is offline
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Re: 1 Victor 2 Window Motors

To weigh in on the 1 victor 2 motors 1 shaft issue:

This is no more dangerous than a 2 victor 2 motors 1 shaft set-up (and might be slightly more forgiving in some circumstances). I'm not saying that running two window motors on 1 shaft is a good idea: I am saying it is an equally bad idea (but not a horrible one).
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Unread 03-05-2011, 10:16
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Re: 1 Victor 2 Window Motors

Quote:
Originally Posted by wiiking123 View Post
Note that these 2 window motors WILL be linked by the same shaft. Although, they will not be turning more than 60 degrees in either direction (the intended use was to be able to move an air cannon barrel up and down). If they are only moving 60 degrees, would I still have the high risk of twisting the shaft? If so, could it possibly be beneficial to simply use 1 window motor to move the shaft?
If you've done the math and determined that 1 window motor will not be overloaded then yes it would be beneficial to use just one motor.

If however 1 window motor would be overloaded, then using 2 motors driven by 1 Victor would be better - but as has been previously mentioned, that setup is not ideal either, because it is vulnerable to cascading failure modes should one of the motors fail.


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Unread 03-05-2011, 10:19
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Re: 1 Victor 2 Window Motors

Would removing the anti-backdrive pins help?
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Unread 03-05-2011, 10:39
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Re: 1 Victor 2 Window Motors

Removing the pins might defeat their purpose of holding the barrel in a particular position.
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Unread 03-05-2011, 11:35
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Re: 1 Victor 2 Window Motors

Quote:
Originally Posted by EricVanWyk View Post
Would removing the anti-backdrive pins help?
Based on my very limited experience, that wouln't help much, if any. They seem designed to make it truly impossible to backdrive the window motor when they are present, but the worm-gear stage is still almost impossible to backdrive with them removed.

If one window motor isn't quite powerful enough for the job, you might be able to get away with using a friction-slip coupling to get enough assistance from a second motor to make things work while avoiding the potential of breaking things when the motors don't quite move in perfect unison.
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Unread 03-05-2011, 18:59
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Re: 1 Victor 2 Window Motors

It may seem very basic, but could using something like rubber tubing as a layer between the shaft and the coupling attached to the SLOWER motor work good enough to avoid twisting the shaft and burning out the motor but still have the motor provide some power in turning the shaft?
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Unread 03-05-2011, 23:39
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Re: 1 Victor 2 Window Motors

If you removed the anti-backdrive pins from one of the motors, then it would slow down/speed up to match the other motor, while still providing torque. Theoretically, that is.

Why don't you just gear down the one motor instead of using a second one? Making gearboxes is a much more valuable skill than screwing together PVC. It would also be lots of fun.
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Unread 04-05-2011, 00:49
wiiking123 wiiking123 is offline
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Re: 1 Victor 2 Window Motors

If only I knew how to make gearboxes. If anybody has any resources they know of like how to design a gearbox, it would be much appreciated! I'm kinda semi alone on making this cannon due to the lack of post-season team members so there are limits one person can do.

Last edited by wiiking123 : 04-05-2011 at 00:56.
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Unread 04-05-2011, 08:24
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Re: 1 Victor 2 Window Motors

Guys,
Let's remember that many teams this year linked two motors together but the difference is that each was fed separately and could be trimmed for differences between the motors. When fed by only one controller, you are stuck if the motor performance is radically different. How critical that difference is unpredictable. It is something you may just have to experiment with to prove. In this application, I think leaving the locking pins might be indicated.
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Unread 04-05-2011, 08:52
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Re: 1 Victor 2 Window Motors

With 2 window motors and 1 shaft there is a possible problem with the locking pins if they are subject to shock loads. The pins on 1 motor could lock with out the other locking. Locking pins and position control with PID also do not mix well. Adding a spring, gas shock to balance the arm would allow 1 motor to do the job.
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Unread 04-05-2011, 12:01
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Re: 1 Victor 2 Window Motors

At St Louis, National Instruments had a tee shirt shooter, that a team built, the plans are on https://decibel.ni.com/content/docs/...#comment-15229. It used one window motor set up as a winch to raise and lower the arm.

I do not think using one or two window motors in a direct drive will give you enough torque to rotate a shooter unless it was well counter balanced.

Last edited by Al Skierkiewicz : 04-05-2011 at 12:16. Reason: fixed link
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Unread 06-05-2011, 23:43
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Re: 1 Victor 2 Window Motors

Safe, yes. Legal, no.

I've seen Victor 884's support waay over 100 Amps (300, to be exact) for short periods of time. For Large periods of time, such current loads tend to be damanging (molten wires, ect)

Now, that being said, as long as you arn't doing crazy loading, the window motors probably are pulling only 4-5 amps combined. Even a cim only draws 2 amps freeload. A victor can handle 10-20 amps all day long without too many difficulties.

Mechanically speaking, even if the motors run at slightly diffrent speeds at the same voltage/amperage, it'll be fine. My team hooked 2 windows together to make a winch for 2011 build... and it was very reliable. and powerful.
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Unread 07-05-2011, 09:03
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Re: 1 Victor 2 Window Motors

Doug,
Window motors stall around 20 amps. There is a difference between the left and right hand motors. 18.6 vs 21 amps. What kind of load produced 300 amps?
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