The AC voltage we talk about is called an RMS or Root Mean Square voltage.
For example 10VDC across a 10 Ohm resistor results in 1A DC current. The resistor will dissipate 10W (IxV). The RMS AC voltage is the equivalent to the DC voltage for power calculations. So 10VAC across the 10 Ohm resistor will also result in 1A RMS. But the power will be 10W. Really handy to know that for choosing the wattage of the power resistor. But because the AC varies, it's both below, down to 0 and above, up to the peak value. The peak is calculated by multiplying the RMS value by the square root of 2 or 1.414; 120V x 1.414 = 170V peak. Given that the AC line can surge up as high as 135V you have to design for 135 x 1.414 = 190V. John Dammeyer > -----Original Message----- > From: John Thornton [mailto:j...@gnipsel.com] > Sent: December-25-15 10:49 AM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Grounding Issues > > > The bridge rectifier is connected to 120v so no transformer is there... > not sure how it gets 190vdc out of 120vac but it does. Now to find some > fuses for it... may be Tuesday before I can use that. > > JT > > On 12/25/2015 12:34 PM, Dave Cole wrote: > > On 12/25/2015 5:59 AM, John Thornton wrote: > >> I wonder if I should put that filter at the beginning of the AC > >> circuit or just ahead of the bridge rectifier? > > I think I would put it prior to the transformer that feeds the bridge > > rectifier, if that makes sense. > > > > That AD VFDs tend to broadcast serious noise back into the AC line. > > I've seen the VFD noise go right through AC to DC power supplies. > > > > Dave > > > > > > > > ---------------------------------------------------------------------------- -- > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > ---------------------------------------------------------------------------- -- > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
