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pic: In_CIM_erator
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#2
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Re: pic: In_CIM_erator
did you look at the specs for those rs775's at 12 volts, at 18 volts they are pretty good, but at 12 volts they produce a measly 70 watts.
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#3
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Re: pic: In_CIM_erator
Quote:
The 18v VERSION at 12v produces much more than that http://banebots.com/docs/M7-RS775-18-AT12V.pdf |
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#4
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Re: pic: In_CIM_erator
lol I'm quite sure they did.
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#5
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Re: pic: In_CIM_erator
pretty sure the 18 volt version is the same, we ran ours and found it MUCH weaker than the RS 550, if anything the 18v version should be weaker than the 12V version, the only difference is the gauge of wire.
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#6
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Re: pic: In_CIM_erator
Any quantitative tests? lifting a load, dynamometer...those spec sheets don't magically appear out of thin air.
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#7
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Re: pic: In_CIM_erator
here is the link to the actual source of the motors, BaneBots Buys them from here, and according to this spec sheet
http://www.mabuchi-motor.co.jp/cgi-b..._ID=rs_755vcwc the "BaneBots rs775 at 12 volts" does somewhere barely above 200 watts at 14.4 volts. the 18 volt version does somewhere around 70. I am fairly sure that the numbers on BaneBots website are inccorrect, they do match up with a larger motor from this supplier. http://www.mabuchi-motor.co.jp/cgi-b..._ID=rs_775vcwc this is the larger motor, but as you can see it is not sold in a 12 volt version, so the 70 watts is close to what this would produce at 12 volts as well, none of the Mabuchi specs come even close to the BaneBots specs. Last edited by Hawiian Cadder : 10-02-2011 at 01:46. |
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#8
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Re: pic: In_CIM_erator
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A motor rated for 18V will run fine on 12V, it will just be roughly 4/9 the power of it on 18V. |
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#9
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Re: pic: In_CIM_erator
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also, power is current * Voltage according to the Bane Bots website peak efficency current is 5.7 5.7 * 12 is 68, which fits the 70 watt power output number, i think all the other info on the BaneBots website is correct, except the power calculation, think that was taken at 18 volts. Last edited by Hawiian Cadder : 10-02-2011 at 02:08. |
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#10
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Re: pic: In_CIM_erator
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If you take the motor at half free speed, it is also at half stall torque, for the 775 this works out to over 250W of power. |
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#11
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Re: pic: In_CIM_erator
Where did the 4/9 come from. I must have missed something in my math.
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#12
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Re: pic: In_CIM_erator
Quote:
Stepping down from 18 to 12V is a 2/3 change. Power = 2/3Torque x 2/3 speed. Works out to the power at 12V being 4/9 that of 18V. |
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#13
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Re: pic: In_CIM_erator
none of the motor specs on the maubichi sheet indicate a power rating of more than 200 watts at 18 volts. thus i dont think it is possible for the 775's to output more than 133 watts MAXIMIUM negating friction.
Last edited by Hawiian Cadder : 10-02-2011 at 02:23. |
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#14
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Re: pic: In_CIM_erator
Ok. I did Power = w/t; w = Fd; F = torque *r. I thought distance and time would stay constant, so I ended up with 2/3 by just changing the torque. Thank you.
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#15
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Re: pic: In_CIM_erator
Quote:
the 18v - RS775 VC Version outputs 208 W or power at max eff. - 18v here is the spec sheet are ya looking at this one? The 775 VC outputs 41.4 W at 12v - 5.7A and 775 VC outputs 156 W at 12v - 18.7A the 775 WC outputs 168 W at 12v - 18.7A and 775 WC outputs 39.9 W at 12v - 5.7A Last edited by ttakashima : 10-02-2011 at 02:41. Reason: Mistake |
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