--===============1875110760== Content-Type: text/plain; charset="gb2312" Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by pch.mit.edu id m2PKn4b2015053 =20 =20 =20 Yes, I would say this is really a problem that goes with money issue. Ple= ase forgive me, I'm just an entry level person and my boss will certainly= not pay me any bonus for fixing the problem caused by previous designers. Thank you both for writing these mails. I appreciate it very much, sorry = it's just spiritually. > From: cc@nope9.com> Subject: Re: [EE] question on a motor noise problem= 2: motor> Date: Tue, 25 Mar 2008 12:41:28 -0600> To: piclist@mit.edu> > = It appears you are asking someone to fix your circuit without any > compe= nsation. Perhaps you should offer someone on this list some $$$ > to walk= you through the whole process.> cc> > > On Mar 25, 2008, at 10:34 AM, ga= rdenyu wrote:> > Hi:> > > This sounds interesting to me. Could please sho= w a little drawing > of how the zener and diodes are put across the relay= ? Thank you very > much.> > This application is for DC motor,actually the= problem never > happened on a small motor, but the controller is just ba= d on a big one.> > > > > From: rgrazia1@rochester.rr.com> To: piclist@mit= .edu> Subject: Re: > > [EE] question on a motor noise problem 2: motor> D= ate: Tue, 25 Mar > > 2008 00:26:30 -0400> > I'm sorry I have not followed= this thread so > > I may be talking out of turn > here. But what is the = picking > > voltage of the relay? Can you try tacking a > zener across the coil > > of the relay? Or a zener and = a fast switching free > wheeling > > diode? If the transient is very fast= , the zener will not work > but > > if it is slow enough it might work. T= he reversed diodes with the > > zener > in parallel might work. Varistors= can sometimes shunt motor > > noise, but > they must be carefully select= ed. Is it a DC motor? Is > > it a servo or > stepper? If it is a DC motor= I am not sure that a > > varistor is a good > choice. I have only used t= hem on AC motors. > > But someone else on the list > would know. I have h= ad good success > > with diodes to shunt transients and > back emf. I wou= ld be > > interested to know how you solve the problem.> > > ----- Origin= al Mess> age ----- > From: "Cedric Chang" > To: > "Microcon= troller discussion list - Public." > Sent: > Monday, Mar= ch 24, 2008 11:42 PM> Subject: Re: [EE] question on a > motor noise probl= em 2: motor> > > > >> >> On Mar 24, 2008, at 5:56 > PM, gardenyu wrote:> >>> >> Thanks a lot for your kind reply.= > >>> >> > I would look at D2 tomorrow, if this is really an issue, do yo= u> >> > have any suggestion on cutting this surge off? RV2 is supposed to= > >> > be a surge protector, maybe it's not strong enough.> >>> >> It's s= ome > new version that I have, for some reason the designer> >> didn't li= ke > the snubber,> >>> >> the relay is certainly a problem, I noticed > b= efore that when it's> >> turned off and not yet turned on, the > voltage = can rise quite high> >> that causes the relay to click back > and forth f= or times. Do you> >> have any suggestion on related > problem? Thank you = so much.> >>> >>> >>> From: cc@nope9.com> Subject: > Re: [EE] question on= a motor noise> >>> problem 2: motor>> Date: Mon, 24 Mar 2008 15:49:53 -0= 600> To:> >>> piclist@mit.edu> > > I would resume that circuitry not show= n ( some> >>> form of logic ) > gets > a surge of voltage applied to it a= nd that> >>> it enters some > unexpected=20 > state. My recommendation is to measure> >>> the voltage > at pin 2 of = D2. > If you are getting drive voltage at> >>> pin 2 > after the "stop" i= s pushed, > then your logic is getting> >>> > hammered by a voltage spike= .> > Are Q4 and Q? ( the Q below Q4 )> >>> > acting as an active motor br= ake ? > The circuitry shown does not> >>> > seem to offer any snubbing of= the > voltage spike you would get> >>> > from the motor. The relay is go= ing to > allow the motor to be> >>> > disconnected for several millisecon= ds, > certainly long enough to> > >>> allow voltage spiking to occur. I a= m > assuming the relay is a> > >>> "break before make" variety, otherwise= I > don't see how the > relay> >>> contacts would survive.> > This desig= n seems a bit strange > to me.> >>> I await the commen> >> ts of o> ther = > PLs. The fact that R25 is missing renders C20 as> >> > useless.> > cc> = -- > http://www.piclist.com PIC/SX FAQ & list> >> > archive> View/change = your membership options at> http://> >> > mailman.mit.edu/mailman/listinfo/piclist> >>> >> > Without seeing the >= rest of your circuit, i cannot suggest a "best> > solution". I can > sug= gest that you put a voltage snubber on the DRIVE> > + line. The > maximum= voltage you apply to the DRIVE+ line dictates> > the voltage > rating of= the parts you use for the voltage snubber. Try> > first > putting an MOV= ( metal oxide varistor ) across DRIVE+ to> > ground. > Multiply the maxi= mum voltage for DRIVE+ by 1.1 and select an> > MOV > that has that voltag= e rating. Without knowing how much current> > > your motor draws and it's= inductance, I would say start with an MOV> > > that absorbs about 5 Joul= es. I also don't know where you buy > parts,> > so I cannot suggest a sou= rce for the MOV.> >> > cc> > -- > > > http://www.piclist.com PIC/SX FAQ &= list archive> > View/c> hange your membership options at> > http://mailm= an.mit.edu/mailman/ > listinfo/piclist > > -- > http://www.piclist.com PI= C/SX FAQ & list > archive> View/change yo ur membership options at> http:// > mailman.mit.edu/mailman/listinfo/pic= list> _________________________________________________________________> = =D3=C3=CA=D6=BB=FAMSN=C1=C4=CC=EC=D0=B4=D3=CA=BC=FE=BF=B4=BF=D5=BC=E4=A3=AC= =CE=DE=CF=DE=B9=B5=CD=A8=A3=AC=B7=D6=CF=ED=BE=AB=B2=CA=A3=A1> http://mobi= le.msn.com.cn/--> http://www.piclist.com PIC/SX FAQ & list archive> View/= change your membership options at> http://mailman.mit.edu/mailman/listinf= o/piclist> > > -- > http://www.piclist.com PIC/SX FAQ & list archive> Vie= w/change your membership options at> http://mailman.mit.edu/mailman/listi= nfo/piclist _________________________________________________________________ MSN =D6=D0=CE=C4=CD=F8=A3=AC=D7=EE=D0=C2=CA=B1=C9=D0=C9=FA=BB=EE=D7=CA=D1= =B6=A3=AC=B0=D7=C1=EC=BE=DB=BC=AF=C3=C5=BB=A7=A1=A3 http://cn.msn.com --===============1875110760== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Disposition: inline Content-Transfer-Encoding: 7bit -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist --===============1875110760==--