Author Topic: hot!!!  (Read 3719 times)

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Offline orchidTopic starter

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hot!!!
« on: February 19, 2008, 10:14:13 PM »
hi all,

i am using escap brushless motor. i have little confusion. why is my motor become so hot? is it motor usually become hot when run about 1-2 minutes? do i have to upload the spec of the motor? plz do reply.

thank you,

Offline airman00

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Re: hot!!!
« Reply #1 on: February 19, 2008, 10:26:12 PM »
give us specs and what voltage you are giving the motor
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Offline orchidTopic starter

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Re: hot!!!
« Reply #2 on: February 19, 2008, 10:37:44 PM »
i am using 13.5Vdc connected to my tms320f2812 board and the motor is connected to the board.


here the data sheet i got from the manual book.

Phase Resistance    7.5  ohm

Phase inductance    480 mH

Back-EMF constant  2.1  V/1000rpm

Torque constant     20  mNm/A

Rated V   10V

Max V   36V

No-Load current 60 mA

Max Cont Current 850 mA

Max cont torque(up to 10000rpm)  17 mNm

Max recommended speed  15000 rpm

Peak current 3A

Peak Torque 60 mNm

rotor intersia 4.7 kgm2.10-7

Mech Time constant 8.6 ms

Thermal resistance rotor body 3 oC/W

Thermal Res body ambient 15 oC/W.

Offline Kohanbash

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Re: hot!!!
« Reply #3 on: February 19, 2008, 10:41:46 PM »
Are you powering the phases correctly (by reading the hall sensors)?

How is the motor/controller wired up?


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Offline orchidTopic starter

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Re: hot!!!
« Reply #4 on: February 19, 2008, 10:55:27 PM »
How to read the hall sensors? Actually, the motor and the hall sensor is connected to the pin on dsp board using connector. the connection already been made by the company so it is not possible that there is any wrong connection. I tried the evaluation software given by TI to operate the motor but when i run it for about 1-2 minutes, it become hot and i shut the power off because i worried that it may damage the motor. is it will damage the motor if it so hot? touching the motor make me feel like touching hot frying pan. :o

Offline Kohanbash

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Re: hot!!!
« Reply #5 on: February 20, 2008, 08:44:39 PM »
How many conductors are going from the motor to the controller
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Offline orchidTopic starter

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Re: hot!!!
« Reply #6 on: February 20, 2008, 09:34:00 PM »


conductor? what is the conductor? if you mean connector, there are 10 wires from motor and 8 from hall sensor connected to the board.

Offline Kohanbash

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Re: hot!!!
« Reply #7 on: February 20, 2008, 09:45:40 PM »
Hi
Conductor is another way of saying wire.

Do you have a data sheet (maybe also a picture) or the motor.
There should only be 3 hall wires
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Offline orchidTopic starter

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Re: hot!!!
« Reply #8 on: February 21, 2008, 01:23:43 AM »
Here I put the details of the pin connector on the motor,

pin 1    GND
pin 2    Vcc
pin 3   Sense
pin 4   /Stand-By
pin 5   A-
pin 6   A+
pin 7   B-
pin 8   B+
pin 9   Z-
pin 10 Z+

I also have attached the datasheet like u ask

Offline Admin

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Re: hot!!!
« Reply #9 on: February 23, 2008, 03:34:47 PM »
Is the motor free spinning or is it being stalled (fully powered but held in place)?

What are you telling the motor to do?

Offline paulstreats

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Re: hot!!!
« Reply #10 on: February 23, 2008, 07:09:31 PM »
It sounds like you are switching phases too slow - or possibly too fast,or one of the coil stages is being powered up but not used. Do you have one of the phases reversed?

Offline orchidTopic starter

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Re: hot!!!
« Reply #11 on: February 24, 2008, 07:54:30 PM »
i have asked my friend about this situation, and he tell me to try variable voltage. first, by using evaluation software i tried 13.5v and the motor become hot.then i try to reduce the voltage to 12v and the motor not as hot as before. after that, i try 10v, the motor seems to be stable.the speed are the same even though i change the voltage. is it the problem solved?

i think about the phase reversed is not possible because i am using evaluation software.
thank you.
« Last Edit: February 24, 2008, 07:57:04 PM by orchid »

Offline airman00

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Re: hot!!!
« Reply #12 on: February 24, 2008, 08:19:09 PM »
the speed is not the same , it appears the same to you but there is a difference in speed

the motor is rated from 10V-36V

it will not "die" as long as the voltage is kept in that range

so it will be hotter at 36V than at 10V


If you have a tachometer you can measure the RPM of it
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Offline orchidTopic starter

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Re: hot!!!
« Reply #13 on: February 24, 2008, 10:16:48 PM »
So is that mean i dont have to worry about the temp if the voltage is still in range? but that temp is pretty hot when i use at 13.5v. i can just touch it for a sec and cant even hold it. im just worried my motor broken or might even explode. thats all. Thanks  :)

Offline ed1380

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Re: hot!!!
« Reply #14 on: February 24, 2008, 10:19:40 PM »
what about a heatsink?

i've sen them for brushless motors

heres the first link in google http://www.rc-monster.com/proddetail.php?prod=RCM01
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Re: hot!!!
« Reply #15 on: February 27, 2008, 09:14:50 PM »
Orchid, I noticed this is an issue with all your posts . . .

You need to answer our questions, and tell us about how you have things set up, for us to help you effectively.

Offline orchidTopic starter

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Re: hot!!!
« Reply #16 on: February 27, 2008, 10:56:35 PM »
Admin..

I am working on a system that using DSP TMS320F2812 motion control kit that is F2812 board attach with PM50 board along with brushless dc motor with hall sensor connected to PWM 1 - PWM 6 on PM50 board. I am using Maxsonar sensor connected to ADC input on the board. the thing is when the sensor detect an object at a certain range, the speed of the dc motor will respond to it. making it slow down or speed up. i have already solve the ADC problem, Heat of the motor and the problem now is about making the motor rotate 360 and looping it for example for 5 second. hope that answer your question.

Thanks a lot.

 


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