Paradise Robotics Forum
Robotic Lawnmowers => Lawnbott => Topic started by: evblazer on July 25, 2010, 07:15:09 PM
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So the 20mm ceramic 500ma 250v T (time delay I think) went out last night. Anyone know somewhere to get one?
Chopper was just going around the perimeter back to the charger and blacked out on the way. Not a blackout just total power off. Battery was at 27.5 volts so that wasn't the problem. Found the ceramic fuse had blown on the motherboard. Maybe I got a bad fuse but I have a note into vishal to see if there is anything I need to check before replacing the fuse.
So anyone else have that little fuse blow on their 35## and/or know what kind of store locally would have one? I tried radio shack, lowes and home depot. I found one online but I'd rather not wait so long for one because the grass is growing well these days.
http://www.newark.com/jsp/search/productdetail.jsp?SKU=26M1200&CMP=AFC-GB100000001 (http://www.newark.com/jsp/search/productdetail.jsp?SKU=26M1200&CMP=AFC-GB100000001)
(http://www.newark.com/productimages/nio/standard/4375419.jpg)
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Ok well tech support has no tests/checks I can do but did confirm that is the correct fuse. Ordered a few since they were only 30 cents but one would cost $5 to get. Also ordered a couple of the next size up in case support tells me to try a bigger one so I won't have to wait another week or two.
Sometimes fuses just go bad hopefully this is one of those times.
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Good luck with that.. I can't ever think of when a fuse blew without cause.
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Well newark standard shipping says it'll be here tommorow so 2 days from when I ordered but $5 shipping.
I am concerned that I'm going to put the new fuse in and it'll work for a minute or maybe 20 then pop again. Is the fuse just not able to do it's 500ma dissapating the heat out in a 100 degree heat* with high humidity in a mostly sealed bot *shug* I hope the fuse was just a dud :-X
* Bots hours are 7am-9am and 6:30pm-9pm in an attempt to avoid direct sunlight at least. I have been asked nicely not to run it at night. Now that the grass isn't beaten down and all brown I may need to expand that somewhat probably a little more in the am.
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Well, we've been getting 90 degree days here in Chicagoland lately and my bot seems to be working just fine. I doubt temperature has anything to do with it failing, but you can hope that overheated motors are drawing more current and blowing the fuse. If I had to guess, something went bad on the main board and you will put the new fuse in and it will instantly blow or you will put it in, and when you turn the bot on, it will blow.
But I'm just guessing.
If you wanted to test at the risk of the main board or a multimeter (most have a low amperage rating), you can always use a multimeter in Amp mode and read how much current it's drawing. If it doesn't burn a component on the main board, it'll probably just blow the fuse on the multimeter. Of course, unless Vishel instructs you to do it, it'll most likely void your warrant. :(
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I just had the same problem, kept blowing those fuses. Just after replacing one I saw a wisp of smoke from the alarm board. I took off the alarm board and found an old un-used speaker behind it with a cut wire hanging off that was shorting on the alarm board. You may want to check for this because I ended up needing all new boards before the robot would operate again. If this is your problem and you have only blown one fuse it may not have caused any further damage as it did in my case.
I think they went to a newer alarm board than my original. Even though this is a new 3510 somewhere along the way it must have been upgraded and all they did was cut the wire to the old speaker and leave it dangling to cause problems.
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I just had the same problem, kept blowing those fuses. Just after replacing one I saw a wisp of smoke from the alarm board. I took off the alarm board and found an old un-used speaker behind it with a cut wire hanging off that was shorting on the alarm board. You may want to check for this because I ended up needing all new boards before the robot would operate again. If this is your problem and you have only blown one fuse it may not have caused any further damage as it did in my case.
I think they went to a newer alarm board than my original. Even though this is a new 3510 somewhere along the way it must have been upgraded and all they did was cut the wire to the old speaker and leave it dangling to cause problems.
Dang I sure do not want to start another negative campaign, but K A and Zucchetti You NEED TO GET SOME QUALITY INTO YOUR ORGANIZATION....
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Wow thanks for sharing that information. I looked over the board briefly but I'll check for the speaker wire.
I had replaced the fuse last night and chopper was out a few hours last night and a few hours this morning without any problems but I'll pull it apart to check for any issues.
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Glass fuses have a low thermal stability and shatter in high-heat conditions. Ceramic fuses, on the other hand, can withstand high temperatures and are more thermally stable. Ceramic fuses, unlike glass fuses, are also often filled with a filler like sand to prevent the formation of a conductive film. When there is a short circuit, the fuse element melts and vaporizes. It deposits on the inside of the barrel or body as a film. In a glass fuse, the body continues to get heated and the film begins to conduct electricity, thus rendering the fuse inefficient. The sand in a ceramic fuse, however, absorbs the heat energy and prevents the fuse from heating and therefore conducting.
You are correct, T is for time delay and TT marking indicates even a longer time delay. I am not sure what they are using that fuse for but since it's only rated at .5 amps of current, its not related to any of the electric motors. It's more common for a glass fuse to fail vs. a ceramic fuse. I am sure they chose a ceramic fuse because a ceramic fuse can handle vibration much better than a glass fuse.
That is a fairly small fuse so it will not take much to cause it to open. Since your fuse is a slow blow rated fuse, it will take more than a half amp of current for a longer period of time to open so it is quit possible it happens again. However you will never know if the fuse was simply faulty unless it opens again. With a glass fuse you can tell a lot by looking at the filament and the glass. You will never know without waiting it out with a ceramic fuse.