<lilipot@[EMAIL PROTECTED]
> wrote in message
news:f646a429-7782-4fd2-9d35-e92eee9b32f5@[EMAIL PROTECTED]
> Hi,
>
> I have a question concerning a boost circuit Vs a dc motor.
> here is a link to a boost circuit:
www.intersil.com/engineeringtools/tools/buckandboostcircuit.pdf
> In the step-up circuit, when Q1 is on, L1 is grounded. I feel that
> this circuit resembles a lot like an electric motor and its coil.
> The analogy is when Q1 is on, it would be like when the brushes makes
> contact with the coils. The duty cycles with the time the brushes has
> contact with the coils.
> I tried implementing this circuit to a dc motor pole and I was not
> getting any boosted voltage.The circuit was the same as shown in the
> link, but I did not add a load resistance, just a big capacitor. Does
> somebody knows why I am not getting a boosted voltage?
> There was not filter or smoothing capacitor on the poles of the
> motor. I used a small electric motor from a remote control car.
>
> lili
Why do you want to use a motor?
A motor is not a simple inductor. True it has an inductive component but
if
the motor turns, it has back emf which would negate any boost effect.
Secondly a motor is a low frequency device. It has high winding
capacitance
and a core that is not suitable for high frequencies. What frequency were
you trying to run your boost circuit?
If you lock the rotor up so it can't turn and run the frequency no higher
than a few hundred hertz, you should see some boost effect in the posted
circuit. Of course the motor inductance will likely be too low for
effective
low frequency operation.
In other word, a motor is not an effective inductor for a boost circuit.
Why
do you want to use a motor?
|
