Silver Can Motor Tips/Tricks
#1051
Tech Elite
iTrader: (8)
I was running it at 82-85 degrees c for 5 races and only got faster but that what i have to gear it to be 2 or 3 secs a lap off top guys although it was a day for hot motors (thats not all my driving that is that slow its a cr@p car so 416 on the way) can anyone explain why it was getting faster? and its done about 4 or 5 meets (5 races a meet) and was run in at no load
btw sorry i ask lots of qs
btw sorry i ask lots of qs
#1052
Tech Master
#1053
Tech Elite
iTrader: (1)
Join Date: Mar 2007
Location: Bristol, England, United Kingdom
Posts: 4,857
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I was running it at 82-85 degrees c for 5 races and only got faster but that what i have to gear it to be 2 or 3 secs a lap off top guys although it was a day for hot motors (thats not all my driving that is that slow its a cr@p car so 416 on the way) can anyone explain why it was getting faster? and its done about 4 or 5 meets (5 races a meet) and was run in at no load
btw sorry i ask lots of qs
btw sorry i ask lots of qs
#1054
Tech Champion
iTrader: (108)
Maybe the magnets were weakened by the heat?? Weaker magnets give you more RPM and less torque.
I was running it at 82-85 degrees c for 5 races and only got faster but that what i have to gear it to be 2 or 3 secs a lap off top guys although it was a day for hot motors (thats not all my driving that is that slow its a cr@p car so 416 on the way) can anyone explain why it was getting faster? and its done about 4 or 5 meets (5 races a meet) and was run in at no load
btw sorry i ask lots of qs
btw sorry i ask lots of qs
#1055
Tech Elite
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Join Date: Sep 2001
Location: Land of the Free, Home of the Brave
Posts: 2,928
Trader Rating: 13 (100%+)
I have been running a silver can at sometimes up to 240F in my TT01. The thing is still crazy fast.
#1056
Tech Elite
I believe the Curie point on the ceramic magnets in a silvercan is in the neighborhood of 800 degrees F. What happens when you overheat a silvercan is you burn up the brushes or the armature, It's very difficult to overheat a motor enough in a car to significantly alter the magnetism. Magnets often weaken slightly with time, but I believe it's due more to vibration, shock etc rather than heat.
#1058
Tech Champion
iTrader: (108)
Then it probably was just continuing to break in and the brushes seat better.
As far as the magnets go...I have for sure 100% watched a car slow because an overheated motor and then have a weak magnetic resistence after cooling compared to before the race....and not just once or twice so...And then checking on a dyno showed less overall power and more RPM.
As far as the magnets go...I have for sure 100% watched a car slow because an overheated motor and then have a weak magnetic resistence after cooling compared to before the race....and not just once or twice so...And then checking on a dyno showed less overall power and more RPM.
#1059
Tech Master
iTrader: (2)
If you test a Johnson 3-5 times in a row (no rest)... you can see the effect of heat reducing torque and increasing RPM. (which is what happens on the track)
If you don't break in the brushes, you can ruin the motor, especially if you gear into it.
Temp, usually hot is the norm for me, anything under 200f usually is pretty safe, unless you don't breakin the brushes.
If you don't break in the brushes, you can ruin the motor, especially if you gear into it.
Temp, usually hot is the norm for me, anything under 200f usually is pretty safe, unless you don't breakin the brushes.
#1060
Tech Elite
Then it probably was just continuing to break in and the brushes seat better.
As far as the magnets go...I have for sure 100% watched a car slow because an overheated motor and then have a weak magnetic resistence after cooling compared to before the race....and not just once or twice so...And then checking on a dyno showed less overall power and more RPM.
As far as the magnets go...I have for sure 100% watched a car slow because an overheated motor and then have a weak magnetic resistence after cooling compared to before the race....and not just once or twice so...And then checking on a dyno showed less overall power and more RPM.
What you've experienced with overheated motors doesn't mean that the problem lies in the magnets getting weaker. It was probably burned brushes or a fried armature. If you'll remember from your TC days, turning the comm and puting in new brushes restored the power in a motor. Some of the guys would rarely buy a new motor, but would keep replacing armatures until the bushings wore out.
Magnets can weaken over time, but will never degenerate to the degree you state in a few runs. I do agree with your observations about overheated motors going slower. I just don't agree that it was due to weakened magnets
#1061
Tech Champion
iTrader: (108)
Gauss meter says differently.
And then once rezapped the motor is back and stronger than before. So I'm not sure I can agree about the magnets
As far as burning brushes and the arm...yes, I've seen that ruin motors too. But they tend to run slower and are very hard to bring back to life. A weakend motor that has weak magnets from being run too hot repeatedly will be returned to it's glory days via zapping most of the time..as long as everything else is taken care of. I've got some 4 slotters that were crap...once zapped and run a few times have shown HUGE improvements over previous performance. And they were checked on a gauss meter before and after zapping. And it's very noticeable on track. So yes, the magnetic strength does weaken. Science doesn't fib.
And then once rezapped the motor is back and stronger than before. So I'm not sure I can agree about the magnets
As far as burning brushes and the arm...yes, I've seen that ruin motors too. But they tend to run slower and are very hard to bring back to life. A weakend motor that has weak magnets from being run too hot repeatedly will be returned to it's glory days via zapping most of the time..as long as everything else is taken care of. I've got some 4 slotters that were crap...once zapped and run a few times have shown HUGE improvements over previous performance. And they were checked on a gauss meter before and after zapping. And it's very noticeable on track. So yes, the magnetic strength does weaken. Science doesn't fib.
What you've experienced with overheated motors doesn't mean that the problem lies in the magnets getting weaker. It was probably burned brushes or a fried armature. If you'll remember from your TC days, turning the comm and puting in new brushes restored the power in a motor. Some of the guys would rarely buy a new motor, but would keep replacing armatures until the bushings wore out.
Magnets can weaken over time, but will never degenerate to the degree you state in a few runs. I do agree with your observations about overheated motors going slower. I just don't agree that it was due to weakened magnets
Magnets can weaken over time, but will never degenerate to the degree you state in a few runs. I do agree with your observations about overheated motors going slower. I just don't agree that it was due to weakened magnets
#1062
Tech Elite
Gauss meter says differently.
And then once rezapped the motor is back and stronger than before. So I'm not sure I can agree about the magnets
As far as burning brushes and the arm...yes, I've seen that ruin motors too. But they tend to run slower and are very hard to bring back to life. A weakend motor that has weak magnets from being run too hot repeatedly will be returned to it's glory days via zapping most of the time..as long as everything else is taken care of. I've got some 4 slotters that were crap...once zapped and run a few times have shown HUGE improvements over previous performance. And they were checked on a gauss meter before and after zapping. And it's very noticeable on track. So yes, the magnetic strength does weaken. Science doesn't fib.
And then once rezapped the motor is back and stronger than before. So I'm not sure I can agree about the magnets
As far as burning brushes and the arm...yes, I've seen that ruin motors too. But they tend to run slower and are very hard to bring back to life. A weakend motor that has weak magnets from being run too hot repeatedly will be returned to it's glory days via zapping most of the time..as long as everything else is taken care of. I've got some 4 slotters that were crap...once zapped and run a few times have shown HUGE improvements over previous performance. And they were checked on a gauss meter before and after zapping. And it's very noticeable on track. So yes, the magnetic strength does weaken. Science doesn't fib.
#1063
for info, what kind or brand zapper do you use for silvercans??????
#1064
Tech Elite
iTrader: (26)
I've got a brand new "Red Dot" silver can Johnson motor from Doc (rccardr) that I just don't need. It's still in the box and has never been run. Pics and more info here:
http://www.rctech.net/forum/r-c-item...cardr-doc.html
http://www.rctech.net/forum/r-c-item...cardr-doc.html
#1065
Any word yet on making black can's/sport tuned motors quicker?