Posted by Daniel who wants to know on January 30, 2011, 3:19 am
> Daniel. Pulse width modulation isn't magic. It is done everyday. Variable
> speed drills, 220v & 440vac motors have drive controllers that do just
> that. Take one apart someday. You might be pleasantly surprised.
> Once the lightbulb in your head comes on, then the possibilities are
> endless. You can do alot with any PWM circuit.
> Jim Rojas
Oh I've already BTDT many times Jimmy boy.
A PWM motor speed controller is a DC-DC buck converter that uses the motor
windings themselves as the inductor, but it ALWAYS slows the motor down when
set lower than 100%. You could drive a DC motor faster with the output of a
DC-DC boost converter but that increases battery amps.
Some VFD AC motor drives uses varying PWM to produce a sine wave, just like
a pure sine power inverter or a class D amplifier, but not all VFDs are PWM
based, some are cycloconverter based.
Posted by daestrom on January 30, 2011, 2:22 pm
On 1/29/2011 22:19 PM, Daniel who wants to know wrote:
>>
>> Daniel. Pulse width modulation isn't magic. It is done everyday. Variable
>> speed drills, 220v& 440vac motors have drive controllers that do just
>> that. Take one apart someday. You might be pleasantly surprised.
>>
>> Once the lightbulb in your head comes on, then the possibilities are
>> endless. You can do alot with any PWM circuit.
>>
>> Jim Rojas
> Oh I've already BTDT many times Jimmy boy.
> A PWM motor speed controller is a DC-DC buck converter that uses the motor
> windings themselves as the inductor, but it ALWAYS slows the motor down when
> set lower than 100%. You could drive a DC motor faster with the output of a
> DC-DC boost converter but that increases battery amps.
> Some VFD AC motor drives uses varying PWM to produce a sine wave, just like
> a pure sine power inverter or a class D amplifier, but not all VFDs are PWM
> based, some are cycloconverter based.
But Jim also mentioned that he's running 18V power tools from a 24V
source through the PWM.
Clearly, 24V will spin a DC motor faster than 18V. So there's no
'magic' here, just Jim is using a different battery pack through the
tools existing PWM controls.
daestrom
Posted by m II on January 30, 2011, 6:42 pm
On 11-01-28 08:51 PM, Curbie wrote:
> That's just Jim Rojas, facts are meaningless, reality proves nothing
> and desperately trying to waste people's time on the impossible.
> First a "magic pipe", now a "magic roof", what magic pipe dream is
> next?
> Curbie
Don't laugh...I have a magic floor. Anything that falls on it becomes
almost impossible to find.
mike
Posted by Jim Rojas on January 30, 2011, 7:02 pm
m II wrote:
> On 11-01-28 08:51 PM, Curbie wrote:
>> That's just Jim Rojas, facts are meaningless, reality proves nothing
>> and desperately trying to waste people's time on the impossible.
>>
>> First a "magic pipe", now a "magic roof", what magic pipe dream is
>> next?
>>
>> Curbie
>>
> Don't laugh...I have a magic floor. Anything that falls on it becomes
> almost impossible to find.
> mike
Curbie will post a chart on how that's not scientifically possible. He
will also argue that anything that falls on the floor goes into a micro
black hole. You just don't understand the principle behind it. These
black holes are all around us... :)
Jim Rojas
Posted by Curbie on January 30, 2011, 8:17 pm
wrote:
>m II wrote:
>> On 11-01-28 08:51 PM, Curbie wrote:
>>> That's just Jim Rojas, facts are meaningless, reality proves nothing
>>> and desperately trying to waste people's time on the impossible.
>>>
>>> First a "magic pipe", now a "magic roof", what magic pipe dream is
>>> next?
>>>
>>> Curbie
>>>
>>
>>
>> Don't laugh...I have a magic floor. Anything that falls on it becomes
>> almost impossible to find.
>>
>>
>>
>>
>>
>> mike
>Curbie will post a chart on how that's not scientifically possible. He
>will also argue that anything that falls on the floor goes into a micro
>black hole. You just don't understand the principle behind it. These
>black holes are all around us... :)
>Jim Rojas
Well that's just as factual as you saying you can create energy from
nothing or 350 gallons will fill a 2000 gallon pool deficit.
More fairy-tails, from someone that truth or reality does not apply
to.
Curbie
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> speed drills, 220v & 440vac motors have drive controllers that do just
> that. Take one apart someday. You might be pleasantly surprised.
> Once the lightbulb in your head comes on, then the possibilities are
> endless. You can do alot with any PWM circuit.
> Jim Rojas