Phase Lock Indicator
in [Design]
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From: Chris on 19 Mar 2010 12:21 I was watching a youtube video about a Nagra reel-to-reel deck and it had a neat little phase lock indication that I would like to duplicate. However, I want to make a stroboscope with an LED illuminating a small white disk with 5 black spokes on it. When the spokes appear stationary phase lock is achieved. The ratio is 5/2. I realize the ratio has to be a whole integer number for this phase indicator to work. This is easy as I can tap the part of my circuit that gives a 10:2 phase ratio and paint 5 spokes on the disks. I am confident it will work. I am just wondering if they make small ac sync motors that will run off of low voltage (i.e. 9V) AC. It would need almost no torque. It would just be turning a tiny white disk over a window in my project. Thanks, Chris Maness
From: D Yuniskis on 19 Mar 2010 12:35 Hi Chris, Chris wrote: > I was watching a youtube video about a Nagra reel-to-reel deck and it > had a neat little phase lock indication that I would like to No, this indicates *frequency* lock. It was also commonly used on some turntables -- with multiple sets of "spokes" (your term) on the platter. > duplicate. However, I want to make a stroboscope with an LED > illuminating a small white disk with 5 black spokes on it. When the > spokes appear stationary phase lock is achieved. The ratio is 5/2. I > realize the ratio has to be a whole integer number for this phase > indicator to work. This is easy as I can tap the part of my circuit > that gives a 10:2 phase ratio and paint 5 spokes on the disks. I am > confident it will work. I am just wondering if they make small ac > sync motors that will run off of low voltage (i.e. 9V) AC. It would > need almost no torque. It would just be turning a tiny white disk > over a window in my project. Presumably, you will be varying <something> to adjust the speed of your motor to bring the "rotating disk" into frequency lock with the strobe? (or, are you varying the strobe rate to cause the disk to "appear" to stop -- it's unclear what your purpose here is) E.g., you might find it easier to use a small *DC* motor (e.g., out of a child's toy) and control the drive to that.
From: Chris on 19 Mar 2010 13:02 On Mar 19, 9:35 am, D Yuniskis <not.going.to...(a)seen.com> wrote: > Hi Chris, > > Chris wrote: > > I was watching a youtube video about a Nagra reel-to-reel deck and it > > had a neat little phase lock indication that I would like to > > No, this indicates *frequency* lock. It was also commonly > used on some turntables -- with multiple sets of "spokes" (your > term) on the platter. > > > duplicate. However, I want to make a stroboscope with an LED > > illuminating a small white disk with 5 black spokes on it. When the > > spokes appear stationary phase lock is achieved. The ratio is 5/2. I > > realize the ratio has to be a whole integer number for this phase > > indicator to work. This is easy as I can tap the part of my circuit > > that gives a 10:2 phase ratio and paint 5 spokes on the disks. I am > > confident it will work. I am just wondering if they make small ac > > sync motors that will run off of low voltage (i.e. 9V) AC. It would > > need almost no torque. It would just be turning a tiny white disk > > over a window in my project. > > Presumably, you will be varying <something> to adjust the speed > of your motor to bring the "rotating disk" into frequency lock with > the strobe? (or, are you varying the strobe rate to cause > the disk to "appear" to stop -- it's unclear what your purpose > here is) E.g., you might find it easier to use a small *DC* motor > (e.g., out of a child's toy) and control the drive to that. Well, adding the DC motor controller would double the complexity of the whole circuit. But looking around I did not find too many low voltage motors, and the ones I did find had reduction gears. I will have to rethink this. My current design has an LED that lights up when lock is achieved, but I am not sure it will be dim enough when the frequency is not locked. I might have to set up some sort of threshold that only indicates when there is a steady lock. Here is my current design: http://chrismaness.com/backend/pulse_converter_v3.jpg Thanks, Chris Maness
From: GregS on 19 Mar 2010 16:14 In article <0406f147-f42c-4dba-86ee-67f4687af33b(a)a10g2000pri.googlegroups.com>, Chris <christopher.maness(a)gmail.com> wrote: >On Mar 19, 9:35=A0am, D Yuniskis <not.going.to...(a)seen.com> wrote: >> Hi Chris, >> >> Chris wrote: >> > I was watching a youtube video about a Nagra reel-to-reel deck and it >> > had a neat little phase lock indication that I would like to >> >> No, this indicates *frequency* lock. =A0It was also commonly >> used on some turntables -- with multiple sets of "spokes" (your >> term) on the platter. >> >> > duplicate. =A0However, I want to make a stroboscope with an LED >> > illuminating a small white disk with 5 black spokes on it. =A0When the >> > spokes appear stationary phase lock is achieved. =A0The ratio is 5/2. = >=A0I >> > realize the ratio has to be a whole integer number for this phase >> > indicator to work. =A0This is easy as I can tap the part of my circuit >> > that gives a 10:2 phase ratio and paint 5 spokes on the disks. =A0I am >> > confident it will work. =A0I am just wondering if they make small ac >> > sync motors that will run off of low voltage (i.e. 9V) AC. =A0It would >> > need almost no torque. =A0It would just be turning a tiny white disk >> > over a window in my project. >> >> Presumably, you will be varying <something> to adjust the speed >> of your motor to bring the "rotating disk" into frequency lock with >> the strobe? =A0(or, are you varying the strobe rate to cause >> the disk to "appear" to stop -- it's unclear what your purpose >> here is) =A0E.g., you might find it easier to use a small *DC* motor >> (e.g., out of a child's toy) and control the drive to that. > >Well, adding the DC motor controller would double the complexity of >the whole circuit. But looking around I did not find too many low >voltage motors, and the ones I did find had reduction gears. > >I will have to rethink this. My current design has an LED that lights >up when lock is achieved, but I am not sure it will be dim enough when >the frequency is not locked. I might have to set up some sort of >threshold that only indicates when there is a steady lock. Here is my >current design: > >http://chrismaness.com/backend/pulse_converter_v3.jpg > >Thanks, >Chris The jpg is hard to view. if you use a transformr you can drive a sync motor with less than 120 volts. A 12 volt secondary might work. 90 volts will drive a 120 volt motor. greg
From: Chris on 19 Mar 2010 15:22
On Mar 19, 1:14 pm, zekfr...(a)zekfrivolous.com (GregS) wrote: > In article <0406f147-f42c-4dba-86ee-67f4687af...(a)a10g2000pri.googlegroups..com>, Chris <christopher.man...(a)gmail.com> wrote: > > > > >On Mar 19, 9:35=A0am, D Yuniskis <not.going.to...(a)seen.com> wrote: > >> Hi Chris, > > >> Chris wrote: > >> > I was watching a youtube video about a Nagra reel-to-reel deck and it > >> > had a neat little phase lock indication that I would like to > > >> No, this indicates *frequency* lock. =A0It was also commonly > >> used on some turntables -- with multiple sets of "spokes" (your > >> term) on the platter. > > >> > duplicate. =A0However, I want to make a stroboscope with an LED > >> > illuminating a small white disk with 5 black spokes on it. =A0When the > >> > spokes appear stationary phase lock is achieved. =A0The ratio is 5/2. = > >=A0I > >> > realize the ratio has to be a whole integer number for this phase > >> > indicator to work. =A0This is easy as I can tap the part of my circuit > >> > that gives a 10:2 phase ratio and paint 5 spokes on the disks. =A0I am > >> > confident it will work. =A0I am just wondering if they make small ac > >> > sync motors that will run off of low voltage (i.e. 9V) AC. =A0It would > >> > need almost no torque. =A0It would just be turning a tiny white disk > >> > over a window in my project. > > >> Presumably, you will be varying <something> to adjust the speed > >> of your motor to bring the "rotating disk" into frequency lock with > >> the strobe? =A0(or, are you varying the strobe rate to cause > >> the disk to "appear" to stop -- it's unclear what your purpose > >> here is) =A0E.g., you might find it easier to use a small *DC* motor > >> (e.g., out of a child's toy) and control the drive to that. > > >Well, adding the DC motor controller would double the complexity of > >the whole circuit. But looking around I did not find too many low > >voltage motors, and the ones I did find had reduction gears. > > >I will have to rethink this. My current design has an LED that lights > >up when lock is achieved, but I am not sure it will be dim enough when > >the frequency is not locked. I might have to set up some sort of > >threshold that only indicates when there is a steady lock. Here is my > >current design: > > >http://chrismaness.com/backend/pulse_converter_v3.jpg > > >Thanks, > >Chris > > The jpg is hard to view. if you use a transformr you can drive a sync motor > with less than 120 volts. A 12 volt secondary might work. > 90 volts will drive a 120 volt motor. > > greg I fixed it. I changed the time constant of the RC circuit that controls the inverters. The nor gate works off of pins 1 and 2 of CD4046. Thanks, Chris Maness |