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Old 11-15-2015, 12:46 PM   #2329 (permalink)
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Originally Posted by Piotrsko View Post
my Kostov has a click temp switch on the brush holder that is set when the holder obviously gets to 215C which turns on an idiot light in the car that says "temp". FWIW they think or have measured 100% duty cycle temps to be less than this amount. the idiot light get checked during start up, but has never come on driving. I did test it once with a hair dryer.
Excellent! The only 'switch' on the Netgain 9 brushes is for wear. The temperature switch on the Netgain 9 is for the stator temperature - which is why I asked. 215C is my answer. Perhaps not for Helwig brushes, but for similar brushes on a similar sized motor.

100% duty cycle is 250 amps at 192v. the armature maximum they recommend is 450 amps at 250v for 4 minutes on an 11" 250 so I extrapolated for my 192 and use 425 max amps. by their charts this is less than 265C comm bar temp. I do pull 450 amps for 3 1/2 minutes accelerating to 65 up a 4.5% hill. I have pushed 800 battery amps @ 180 sag volts, but get this burning clutch and wiring smell before the controller shuts down my throttle requests.
'burning clutch and wiring smell' Hopefully the wiring smell is not the varnish in the motor, but the wiring to and from? 800 amps sounds like you are pushing pretty hard.

The netgain numbers are in their FAQ here

But there are some contradictory numbers in here

What I will start with is:
' the 9 motors are actually rated at 450 Amps for 5 minutes,
225 Amps for 1 hour,
and 190 Amps continuous duty.
We believe these are conservative ratings. '
I'm not using a DC controller. I have 3, in various stages of broken and needing repair. For now I'm running 'across the line' on 2s3p 12V deep cycle batteries with a gigavac contactor and a 350 amp fuse. 27.6V will not overspeed the unloaded motor, but will put energy into the DC motor to spin the AC motor that is coupled to it.

I'm trying to test the AC controller at load. The AC controller has a 125V pack on it, which is too high to run the Warp9 without a controller. To minimize the current draw on the gigavac when it closes across the 24V pack, I actually start spinning the AC/DC motors coupled with the AC controller.

now this leads to the rocket scientist question: where exactly do you want to see what temperature on the comm. the brushes got way hotter, there is this little plasma arc thing going on, some parts are not conducting and therefore radiating heat.......I digress.
I want to make sure I don't melt something. 215C seems like a good start. No DC controller = NO CURRENT LIMIT. So I am the control system - sensing with an infrared thermometer, actuating the gigavac to stop the DC motor.

The contact point from the brush to the commutator would seem to me to be the highest temperature and the point at which you would see damage to the brushes or to the commutator. Using the infrared thermometer is not overly accurate, but neither is the rest of my test rig ..

so: what is the S60 rating? or worse case what is the motor rated for in watts or HP? If you stay under those figures, the comm should be OK for temps
225 amps for 1 hour, but my 24V pack won't last for an hour.
400 amps for 5 minutes. I can see trying that out, if the old deep cycle batteries will put out 400A for 5 minutes.
HP was listed at 32.3 HP (72 Volts, 335 Amps). Which is the contradiction I mentioned above.
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