I am not using a transformer, I'm using our mains supply which is 220VAC...

Question: Will the very nature of PWM on the motor not cause the average
voltage to drop below the accepted range in any case? Then I just have to
make sure I don't switch the motor on at 100% duty cycle.

Thanks!
Kevin


-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Sean H. Breheny
Sent: 14 April 2002 05:31 AM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [EE]:High power DC switching..


Hi Olin,

I think he means a full wave rectifier using two diodes and a center-tapped
transformer, to give half voltage.

Sean

At 07:55 PM 4/13/02 -0400, you wrote:
> > > Something else bothers me a bit. I have just read through the spec of
>the
> > > motor and I don't think this motor can handle more than 220V DC. Our
>mains
> > > supply is 220V Ac. Putting that through a bridge rectifier and a cap
>will
> > > probably push it to 320 V DC!! which is miles to much. What can I do
to
>get
> > > this down to around 200V DC again?
> >
> > You could use a half-bridge rectifier -- two diodes instead of four.
>
>You could, but you'd still end up with the same maximum voltage.  It would
>just droop more between the peaks.
>
>
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