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View Full Version : broad electric brushed motor question/charger ?



diesel1984
04-24-2007, 08:26 AM
can you tell when a motor is beginning to die i guess(need a new one) i have a 700sc ran it like maybe 9 times on 16 cells...any idea how long it should last or no...how long the run times may be as well? they seem to vary so not sure what i should run it as far as time goes. I ran it three times yesterday, and did fine...but is that hard on the motor? it was done around 9am, 12 30pm, and 4 30 pm. thanks, michael
Is it normal for the motor to smell also(like mild electrical, i dont think its the ESC, could the diode be coming off causing that or no)...sign of break in or what. also how do you break a motor in with the MRC 989 charger?

Steven Vaccaro
04-24-2007, 09:54 AM
its shouldnt smell too much. The smell is the coating burning off the windings. Thats a bad thing. What temps are the motor when you come in?

SweetZ28
04-24-2007, 11:52 AM
Yes a smell is very bad that most likely means you over ran it and strained it to the point of over heating.

Break in a motor you can use 2 D cells at 3Volts and run it for like 8 to 10 Min on that or put it under water and run it for like 3 min and it should be good.

diesel1984
04-24-2007, 12:54 PM
so can i still run it though or will it mess up other things? there was never any smoke or anything

Fluid
04-24-2007, 06:40 PM
From your description it sounds like you might have cooked that motor. Running a cooked motor may cause the ESC and cells to run hotter than usual, and of course the boat will be slow..... :(

So that you do not make the same mistake again...what boat, what prop, is it submerged or surface drive (is the prop part way out of the water when running)? What kinda cells and how long was each run? You were wise in letting the motor cool down plenty between runs. :)



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diesel1984
04-24-2007, 09:37 PM
i have cen aqua jet extreme, the prop is cf 42 , i think its subsurface drive...doesnt come out under hull. 16 cells IB 4200 (2 9.6v) each run was prolly 6 minutes or less i believe. Also i never broke the motor in.. 700sc since i didnt know to do so... i have jet navy 600 ESC, with sermos connectors. I honestly dont see how i over cooked it but i did notice say 30 seconds before i brought the boat in for the final time where i smelled the electrical burn you could say it took like a 10-15 mph drop as i brought it in full throttle.

Fluid
04-25-2007, 07:26 AM
Yes, you have destroyed the motor. A 42mm submerged mono prop is 'way too much for 16 hot cells, and running it for 6 minutes cooked it good. When you increase the number of cells on a motor, you will usually need to prop down, especially with a submerged drive. The high load and long run time got the motor good and hot - you smelled the result. A 42 mm prop might work okay on a hydro with a surfacing prop, but even then I'd prefer a 40mm. On a submerged drive, 38mm tops especially if you want to run for a long time.

You do not need to break in a motor, that process just helps the motor run faster sooner and last a little longer.


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boater76
04-25-2007, 08:55 AM
There was a thread that had to do with the 700sc motor and the amount of cells used with it. I believe anything over 14 cells on the 700 would decrease motor life. Do a search for it. I have the same motor and I plan to use 14 on my hull with plenty of cooling.

Ken