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Ok, so I'm testing my first Pro Boat 1500kv motor from a Miss Geico using the stock 45amp ESC. I have opened up this motor, inspected the rotor/stator/windings and installed new ceramic bearings. The lowest cell count I can put together here is 5s (Both Trinity Titaniums - one 2s 5500mAh, and one 3s 4500mAh). All I wanted to do was test it out real quick and it seems to get pretty hot after about 15-20 seconds of full throttle. I'm holding it, so its not burning hot, but I'm just not sure that it should be getting warm at all after such a short burst, unloaded... I tried it on only 3s with a higher amp ESC and it seemed to react the same. I don't have any experience with this motor to diagnose it or to know that its behaving normally.
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15 to 20 seconds of free running is NOT short burst. 1 or 2 seconds is.
Nortavlag Bulc -
It should not get hot. You have something binding. Maybe case is bent, misaligned, the rotor rubbing the winding? You have corrosion x in it? If so, try cleaning that out. Smooth the inside with some 400 grit. If none of the above works then your windings are shot or shorted. I can run mine in my hand for a while and it doesn't get warm.32" carbon rivercat single 4s 102mph, 27” mini Rivercat 92mph, kbb34 91mph, jessej micro cat(too fast) wasComment
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I agree that it should not get hot, on the other hand, as Ray says, 15-20 sec. is a long time for revving a motor unloaded, it will def. get warm. Very few of us would actually hold full throttle for that long bench testing.Too many boats, not enough time...Comment
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Even unloaded? Just a free shaft with not even a collet attached? I've made sure I can see daylight 360 degrees around the rotor. Plenty of gap. I think I may take it back apart and try to get the stator out without damaging it. I think they glue those into these motors also. That won't be fun. I've never had to re-do windings.
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Maybe I should add, during the bearing break-in run of over 5 minutes at approx 1/4 throttle, it didn't get warm at all.Comment
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Exactly how did you install the bearings and or what tools did you use to do it? I've never bothered to break in bearings or a brushless motor, don't see a need specially at 27,000rpm or so. Nortavlag Bulc Comment
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Motor is still loaded in the car driving the drivetrain... I'm not trying to cut anything down you do, just some things I've never heard of.
I'm still wondering if the bearing install went o.k. or maybe they were damaged during install... Your motor is most likely fine I hope.
Nortavlag Bulc Comment
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There you said it yourself: "1/4" throttle.
I usually do not get into arguments, but I was just saying WOT for 15-20 sec. is a long time for bench testing, nowhere I was saying a loaded motor will run more efficiently, THOSE ARE YOUR WORDS!!!Too many boats, not enough time...Comment
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I actually used the rotor shaft to keep the rear bearing centered on getting it started. I was very gentle with everything. Once the bearing was started, all I had to do was reach in with my pinky finger, apply a little pressure and it slid right in. Then I put a little extra pressure on it with the flat end of a small screwdriver handle, just to make sure it was seated all the way. Then I applied CA glue to the outer race where it stands just above the case. That's how the old bearings were glued in when I removed them. I had the front cover off the motor so I gently pressed it in with my finger also. It gave no resistance. I soaked the bearings in full synthetic oil and got all the little air bubbles out to insure they were fully saturated inside. The break in for these bearings is what the manufacturer recommended to prevent the ceramic balls from "skidding."Comment
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I hope I didn't type something to make it sound like I was arguing. I'm really new to this and am honestly asking with no sarcasm or anything. The motor will spin at low RPM without generating any heat, but as soon as I take up to half throttle or beyond, it starts getting warm fast. So you're saying that is the expected result for this scenario? I want to be sure because I have this motor listed for sale, and I don't want to sell anyone a bad part. Only looking for advice to make sure this little motor is operating like it should be.
Thanks,
Michael P.Comment
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No worries! all is good.
The interesting thing is that when you were doing the 1/4 throttle, did you by any chance touch your ESC, bet that was warm. ESC works harder when it is not WOT, motor is a different story. I have had the experience of doing WOT---bench testing ( although not as long as you had done) and the motor was warm, but it is just warm, I am not clear how warm is warm in your case. Since you feel the need to ask questions, there might be a possibility that yours is too warm. I think you are on the right track to investigate further so no mishap will occur down the road.
Just a gentle heads up, 15-20 sec. is long and I hope my comment wasn't taken as criticism, so in this regard I owe you an explanation as well.
Cheers!Too many boats, not enough time...Comment
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Well Mike, I'm not much into ceramic bearings because they can be so easy to damage on installation. I would just test the motor under load to see if it performs as normal. I'm curious as to how you can control the flow of CA to get into the tighter gap of where it sits and not in any gaps of the bearing cover. I've never used glue to hold a bearing in place before, usually the races keep my bearings in place without it.
Until it's load tested I'm afraid we are all guessing. Nortavlag Bulc Comment
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Ok, thanks! I was worried that there was something taken not the way I intended. I may take it to my local hobby shop and have them look at it as well. After what you guys have said, I really feel like I'm not prepared to properly test these brushless motors. My intuition says, motor hot = something wrong, lol. But it sounds like my method is flawed. I've been trying to search for info in forums, and what I find most in people with motors getting hot is they simply don't have the right battery/ESC setup for the motor, or in the case of planes, boats and cars, they are propped or geared incorrectly... Hadn't found any good reads or vid's on bench-testing.Comment
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