2002.09.13, 04:28 AM
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#1
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Registered User
Join Date: Nov 2001
Location: makati, philippines
Posts: 8,702
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current draw from motors
i was wondering if anybody knows how to determine the current draw on motors... like how much current would a stock motor, x-speed motor have... not to mention some other hand wound motors...
i'm asking this because i want to know the max current that a stock mini-z can take without busting the fets...
i also want to know how much current can the irf7389 fet take...
in 2, 4, 6, 8, 10, 12 multiples...
like i have 6 irf7389 fets that replaced the 3004 fets...
how much current can it take without busting?
any input appreciated
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2002.09.13, 04:56 AM
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#2
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Mini-Z Chief
Join Date: Jan 2002
Location: UK, Hemel Hempstead
Posts: 691
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I am sure there must be a formula for this based on winds and wire thickness.
I know a web page exist that has the Tamiya 4wd stats.
Dunno about the mini-z stuff.
I guess you just need and a multi meter and the means of loading the car at full throttle while stationery.
I am not much help am I
__________________
Haynes Manual: Prise away plastic locating pegs...
Reality: Snap off...
Haynes Manual: Lightly...
Reality: Start off lightly and build up till the veins on your forehead are throbbing then re-check the manual because this can not be 'lightly' what you are doing now.
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2002.09.13, 07:38 AM
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#3
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Registered User
Join Date: Jul 2002
Location: Ottawa, Ontario
Posts: 889
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You just need 1 hand for the multimeter, 1 hand for the radio, and one hand to hold the car down...
*hmm* i wonder where I could get that third hand....
__________________
-Scott
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2002.09.13, 08:21 AM
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#4
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Mini-Z Chief
Join Date: Jan 2002
Location: UK, Hemel Hempstead
Posts: 691
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Kwiki Mart?
__________________
Haynes Manual: Prise away plastic locating pegs...
Reality: Snap off...
Haynes Manual: Lightly...
Reality: Start off lightly and build up till the veins on your forehead are throbbing then re-check the manual because this can not be 'lightly' what you are doing now.
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2002.09.13, 11:15 PM
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#5
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Registered User
Join Date: Jun 2002
Location: Redwood City, CA
Posts: 562
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I did this when I wanted to test current draw on a low wind motor I'd just made. Get four batteries and tape them together so they touch end to end. Tape the motor neg wire to the neg post on one end of the batts, then place a multimeter between the pos post of the batts and the pos motor wire. Complete the circuit and you'll be measuring the current flowing to the motor.
Motors draw the most current at near stall speed under load, so you can squeeze the output shaft between your fingers or whatever to simlutate a high load condition. Read the values off the meter while doing this and you should have a good idea of current draw. HTH,
ianc
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2002.09.13, 11:23 PM
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#6
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I am a Z-aholic ;)
Join Date: Jul 2002
Location: Melbourne, Australia
Posts: 706
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To solve the necessity for 3 hands, I have bought some alligator clips that slip over the MM probes, and so you just clip them in line with the motor fromthe batterie on the positive wire, and you ahve hands free to do the necessities i.e. trigger throttle, load up motor shaft to simulate loading. I also use a battery pack from a receiver set, as it has a switch, and plugs going to a servo plug. Just gently remove the metal terminals from the servp plug by prying up the clips(you'll see them) and you can then just alligator clip them together, or whatever turns you on. Easy done
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2002.09.14, 12:28 AM
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#7
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Registered User
Join Date: Jul 2002
Location: Ottawa, Ontario
Posts: 889
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post results here :-)
__________________
-Scott
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2002.09.14, 10:21 PM
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#8
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Administrator
Join Date: Nov 2001
Posts: 8,497
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Actually we tested all of the major motors and have full stats; it's going to be an article as soon as I get my new NML motor for completeness. When measuring, make sure you do it under load, or you'll get very inaccurate results.
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2002.09.15, 06:01 PM
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#9
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Tamtech veteran
Join Date: May 2002
Location: Scandinavia
Posts: 95
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"going to be an article"...
I've been asking for that one for ages... Please publish it now and fill in the NML when it arrives. Next x-mas or something :-)
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2002.09.15, 07:50 PM
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#10
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Mini-Z Novice
Join Date: Sep 2002
Location: sydney
Posts: 24
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Yup....please please please........
i dont want to fry my new 4 fets (irf7369)
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2002.09.15, 11:04 PM
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#11
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Administrator
Join Date: Nov 2001
Posts: 8,497
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Well, the other sticking point is the new content engine we're working on which will house all articles etc...
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2002.09.16, 10:58 AM
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#12
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Mini-Z Novice
Join Date: Sep 2002
Location: sydney
Posts: 24
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Hmm......i was just wondering, i just installed 4 fets (IRF7389) replacing the original.
And, my question is:
which Tamiya 4wd motor can i use?
Thank you
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2002.09.16, 12:46 PM
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#13
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nomotorlimit@hotmail.com
Join Date: Dec 2001
Location: California
Posts: 2,072
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this sounds good. I will make the motor for mzr.com this week.
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2002.09.20, 01:54 AM
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#14
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Mini-Z Pro
Join Date: Jul 2002
Location: Hong Kong
Posts: 100
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Quote:
Originally posted by co_doc
Hmm......i was just wondering, i just installed 4 fets (IRF7389) replacing the original.
And, my question is:
which Tamiya 4wd motor can i use?
Thank you
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If you want the performance close to Xspeed. (sure is better!) Try Torque Turn! (Orange one). It use SWG 31 / 50 Turn.
If you want amazing speed. Hyper Dash 2 (Red one). It use SWG 30 / 35 Turn.
This two motor is enough to run. But need turbo or Stack FET.
Of course, if you know how to wound motor. Try SWG 30 / 35, 38, 40 Turn this 3 setting is very good. But need to use atomic turn magnetic.
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2002.09.21, 12:08 AM
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#15
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Mini-Z Novice
Join Date: Sep 2002
Location: sydney
Posts: 24
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thankz BJS-TF.....
i currently using x-speed, so i guess i'll try the hyper dash (any diff with hyper-dash & hyper dash 2 ?) with the 2 fets stacked together.
Thankz again for the info.
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