--===============0720930935== Content-Type: text/plain; charset="gb2312" Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by pch.mit.edu id m2PNd869026942 Yes I did. The schematic really makes sense. =20 I'll try to pick up some components from Digikey tomorrow. Thanks. > From: rgrazia1@rochester.rr.com> To: piclist@mit.edu> Subject: Re: [EE]= question on a motor noise problem 2: motor> Date: Tue, 25 Mar 2008 19:08= :39 -0400> > Were you able to open the schematic?> ----- Original Message= ----- > From: "gardenyu" > To: "Microcontrolle= r discussion list - Public." > Sent: Tuesday, March 25, = 2008 4:48 PM> Subject: RE: [EE] question on a motor noise problem 2: moto= r> > > >> >> >> > Yes, I would say this is really a problem that goes wit= h money issue. > > Please forgive me, I'm just an entry level person and = my boss will > > certainly not pay me any bonus for fixing the problem ca= used 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.ed= u> > > >> It appears you are asking someo ne to fix your circuit without any > > >> compensation. Perhaps you shou= ld offer someone on this list some $$$ > to > >> walk you through the who= le process.> cc> > > On Mar 25, 2008, at 10:34 > >> AM, gardenyu wrote:> = > Hi:> > > This sounds interesting to me. Could > >> please show a little= drawing > of how the zener and diodes are put across > >> the relay? Tha= nk you very > much.> > This application is for DC > >> motor,actually the= problem never > happened on a small motor, but the > >> controller is ju= st bad on a big one.> > > > > From: > >> rgrazia1@rochester.rr.com> To: p= iclist@mit.edu> Subject: Re: > > [EE] > >> question on a motor noise prob= lem 2: motor> Date: 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 > >=20 diode? If the transient is very fast, > > the zener will not work > but = > > if it is slow enough it might work. The > > reversed diodes with the = > > zener > in parallel might work. Varistors can > > sometimes shunt mot= or > > noise, but > they must be carefully selected. Is > > it a DC motor= ? Is > > it a servo or > stepper? If it is a DC motor I am > > not sure t= hat a > > varistor is a good > choice. I have only used them on > > AC mo= tors. > > But someone else on the list > would know. I have had good > > = success > > with diodes to shunt transients and > back emf. I would be > = > > > interested to know how you solve the problem.> > > ----- Original M= ess> > > age ----- > From: "Cedric Chang" > To: > "Microcon= troller > > discussion list - Public." > Sent: > Monday,= March 24, > > 2008 11:42 PM> Subject: Re: [EE] question on a > motor noi= se problem 2: > > motor> > > > >> >> On Mar 24, 2008,> > at 5:56 > PM, ga= rdenyu wrote:> >>> >> Thanks a lot for yo ur kind reply.> > > >>> >> > I would look at D2 tomorrow, if this is rea= lly an issue, do you> > > >> > have any suggestion on cutting this surge = off? RV2 is supposed to> >> > > > be a surge protector, maybe it's not st= rong enough.> >>> >> It's some > > > new version that I have, for some re= ason the designer> >> didn't like > > > the snubber,> >>> >> the relay is= certainly a problem, I noticed > before > > that when it's> >> turned of= f and not yet turned on, the > voltage can > > rise quite high> >> that c= auses the relay to click back > and forth for > > 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 -0600> > > To:> >>> = piclist@mit.edu> > > I would resume that circuitry not shown ( > > some> = >>> form of logic ) > gets > a surge of voltage applied to it and > > tha= t> >>> it enters some > unexpected> > > s tate. My recommendation is to measure> >>> the voltage > at pin 2 of > >= > D2. > If you are getting drive voltage at> >>> pin 2 > after the "stop= " > > > is pushed, > then your logic is getting> >>> > hammered by a volt= age > > > spike.> > Are Q4 and Q? ( the Q below Q4 )> >>> > acting as an = active > > > motor brake ? > The circuitry shown does not> >>> > seem to = offer any > > > snubbing of the > voltage spike you would get> >>> > from= the motor. The > > > relay is going to > allow the motor to be> >>> > di= sconnected for > > > several milliseconds, > certainly long enough to> > = >>> allow voltage > > > spiking to occur. I am > assuming the relay is a>= > >>> "break before > > > make" variety, otherwise I > don't see how the= > relay> >>> contacts > > > would survive.> > This design seems a bit st= range > 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 & > >=20 > list> >> > archive> View/change your membership options at> http://> >= > > > > >> > mailman.mit.edu/mailman/listinfo/piclist> >>> >> > Without s= eeing the > > > rest of your circuit, i cannot suggest a "best> > solutio= n". I can > > > suggest 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. Tr= y> > first > > > putting an MOV ( metal oxide varistor ) across DRIVE+ to= > > ground. > > > Multiply the maximum voltage for DRIVE+ by 1.1 and sele= ct an> > MOV > that > > has that voltage rating. Without knowing how much= current> > > your motor > > draws and it's inductance, I would say start= with an MOV> > > that absorbs > > about 5 Joules. I also don't know wher= e you buy > parts,> > so I cannot > > suggest a source for the MOV.> >> >= cc> > -- > > > http://www.piclist.com > > PIC/SX FAQ & list archive> > V= iew/c> hange your membership options at>=20 > > > http://mailman.mit.edu/mailman/ > listinfo/piclist > > -- > > > ht= tp://www.piclist.com PIC/SX FAQ & list > archive> View/change yo> > ur me= mbership options at> http:// > > > mailman.mit.edu/mailman/listinfo/picli= st> > > _________________________________________________________________= > =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://m= obile.msn.com.cn/--> http://www.piclist.com > > PIC/SX FAQ & list archive= > View/change your membership options at> > > http://mailman.mit.edu/mail= man/listinfo/piclist> > > -- > > > http://www.piclist.com PIC/SX FAQ & li= st archive> View/change your > > membership options at> http://mailman.mi= t.edu/mailman/listinfo/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> > > ----------------------------------------= ----------------------------------------> > > > -- > > http://www.piclist= .com PIC/SX FAQ & list archive> > View/change your membershi p options at> > http://mailman.mit.edu/mailman/listinfo/piclist> > >=20 _________________________________________________________________ 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 --===============0720930935== 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 --===============0720930935==--