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#1 jeff

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Posted 05 October 2002 - 12:57 AM

I am currently trying to source a stepper motor and find different volt/amp combinations for the same torque outputs. As an example, one here has 2.0 amps at 5.0 volts per phase and the next has 4.0 amps at 2.5 volts. Both motors have the same 6 leads in this case. I have no problem seeing that both would output the same power but, what i don't understand is how is the 'correct' voltage applied by the drive? I see no evidence of voltage settings on any of the drives i have been checking out...

#2 jeff

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Posted 06 October 2002 - 05:05 AM

Ok, so nobody knows anything about steppers. I know even less. I have been studying bit today and and may have found a part of the answer myself. It's quite possible that the motor with the lower resistance/higher current reaches it's rated torque sooner on each step. The only benefit that comes to mind here might be quicker acceleration.

I'll keep digging and let myself know whenever i find out...
:-)

#3 BigMax

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Posted 07 October 2002 - 04:11 AM

Hi Jeff!

From memory (it's been a while since I last played with a stepper motor), the reason you have 2 seemingly similar stepper motors is all to do with the maximum stepping speed for which each is designed.

I think the lower current higher Voltage version would be designed for optimal performance up to a maximum of around 160 steps per second for a small stepper, when running from a stepper drive with 5V nominal source.

The high current / low Voltage device may be suitable for 'high speed' operation with added external resistors to decrease the time constant / increase the current rise time (...Tconst = L/R, remember). This combination requires a stepper drive with a higher source Voltage (~12V?) and results in higher overall losses.

I must admit I'm a bit rusty on all this.

Does this help?

Cheers!

BigMax:)




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