Post by thread:[EE]: Stepping down voltate (12V -> 6V)

> I am making a stepper motor controller driven with a pic. The motors I have > are .8A (7.5Ohm), 6V motors. > I plan to use a 12V SLA battery. > > I am using a 7805 V. Regulator to regulate the voltage going into the PIC, > but in addition to this im going to need 6V to drive the steppers. You don't need to drop the voltage to the stepper motors. Use a resistor in series (ie voltage divider with the coil resistance) . If you look up any tutorial on stepper motors you'll find that they work much better (ie have more torque) at higher supply voltages. I don't have my stepper motor info to hand but if you drive them with pulses (I think) rather than static or slow DC-like waveforms you can get rid of the resistors too. But don't quote me on that. I advise you look on the web for a tutorial, quite a few around -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

At 10:02 PM 9/30/00 +1200, Jinx wrote: > > I am making a stepper motor controller driven with a pic. The motors I >have > > are .8A (7.5Ohm), 6V motors. > > I plan to use a 12V SLA battery. > > > > I am using a 7805 V. Regulator to regulate the voltage going into the PIC, > > but in addition to this im going to need 6V to drive the steppers. PBL3717 chopped drivers will let you happily run a "5v" motor on a 24V supply. Efficiently too. It's all about current. Voltage is incidental, you just need to make sure you have enough. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

If I use a resistor in series I would need a very large resistor that could handle 10W.. Greg {Quote hidden}>You don't need to drop the voltage to the stepper motors. Use a >resistor in series (ie voltage divider with the coil resistance) . If you >look up any tutorial on stepper motors you'll find that they work >much better (ie have more torque) at higher supply voltages. I >don't have my stepper motor info to hand but if you drive them >with pulses (I think) rather than static or slow DC-like waveforms >you can get rid of the resistors too. But don't quote me on that. I >advise you look on the web for a tutorial, quite a few around > >-- >http://www.piclist.com hint: The list server can filter out subtopics >(like ads or off topics) for you. See http://www.piclist.com/#topics > > _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.com. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

> If I use a resistor in series I would need a very large resistor that could > handle 10W.. > > Greg The link I posted yesterday is Part 3 of a series. Use the "Stepping Motors" link at the top of that page to get to the index for the whole series. Part 4 covers Current Limiting http://www.cs.uiowa.edu/~jones/step/current.html -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics