A Motor without sync

[McGee2021]

I was wanting to make a television, but this time without sync. I was wondering if it would be more complex, if even possible. And, if possible, would it need continuous adjusting?

[Harry Dalek]

I was wanting to make a television, but this time without sync. I was wondering if it would be more complex, if even possible. And, if possible, would it need continuous adjusting?

Well yes you can make a manual motor controlled monitor ,if your doing it with a DC motor i would use PWM ,a bit better would be a stepper motor might have to use a pulley system to get the right speed depending on how many lines your wanting to show ..even with a stepper the picture will drift ...

Both are enough to get a picture but with out locking onto that sync with feed back from the disk via an encoder to either a pll or bistable circuit to control the motor it will drift and you will have to adjust that speed control pot .

[Klaas Robers]

It is very well possible to make a Nipkow disc monitor (Televisor) without sync. Then you should carefully adjust te motor speed and look at the picture that it produces. With your finger against the disc you may fine tune the speed.

You will experience that it is difficult to keep the picture stable in the viewing window, but you get a picture !! In fact this is the way to start. These first pictures are the finest that you will see: IT WORKS!! Then almost immediately you are wanting to have an automatic synchronisation, such that the disc keeps running synchonously to the video signal and you don't have to synchronise continuously by hand. But this is the second generation. It is an extension on what you have built. Always proceed in that way: step by step. It will give you much more satisfaction than making it perfect at once. See that you have results as soon as possible and then improve.

But first you need a video signal. That is the source. The NBTVA (http://www.nbtv.org) can provide you with a CD with almost perfect NBTV video signals. Otherwise you have to make that as well.

A different aproach is to make a camera and a monitor in one, on both sides of the same disc. Then you have left the camera and right the monitor (viewing part). Then you don't need any synchronisation, as the same disc is used. But then you might doubt if this is televion, because "tele" is "far away", and this is just meters away. On the other hand you have the electronic problems of the camera and the monitor at the same moment.

Good luck.!

[McGee2021]

Thank you for the answers. Another question, where could i get a sync motor with four leads? I have looked every where and all I could find was the modern 3 lead.

[Klaas Robers]

There are no synchronous motors with 4 leads. These are called stepper motors. Syncchronous motors run on AC on one coil and the same AC on the other coil via a capacitor. However, internally they have two separated coils, of which the "bottom" end is connected to one and the same binding post. If you open the motor, you might separate the two coils, create a fourth binding post for the other bottom end, or simply solder a piece of wire to it that comes out.

Most stepper motors can be run as synchronous motors, but will run far too slow. The strength of stepper motors is that they can make very small steps and be still accurate. A Nipkow disc should run 12.5 rev / sec.

May be you can help yourself with a bike dynamo, the type that has a small ribbed wheel that is pressed against the front tyre. You can check it, when you turn the small wheel, it should have 8 positions that it "likes". Most of them are of this type. If you connect that to a bell transformer, 5 or 8 volt 50 Hz, and you give the wheel a turn by hand, it will keep running at 12.5 rev/sec. synchronously to the mains (power grid). Then it is almost correct, although the picture will move slowly out of the viewing window. The mains is not that precisely 50.0000 Hz.

With a Nipkow disc mounted in stead of the small wheel (generally with nuts M 4) the starting is not that easy. Then the disc can be spun up with a motor from an old cassette recorder and a rubber belt. When it is on speed, you can see that with a stroboscopic disc, you switch on the bell transformer and the disc runs synchronised to the mains.

But you could also run it on an 50 Hz AC voltage that you generate electronically yourself, and which is synchronised to the incoming video. A simple audio amplifier can bring this to sufficient power. In this way it is possible to climb up step by step.

[McGee2021]

Another question. Where could i buy a motor similar to the original Baird motor? Or would i have to make one myself

[Harry Dalek]

Another question. Where could i buy a motor similar to the original Baird motor? Or would i have to make one myself

I would follow Klaas advice on the motor ,but if you have the skills to make one its the only way i can think of to answer your Question .....not many make motors and here i can't think of one that has done it or have the urge ,in the past Literature i have read of low def tv hobbyists making them,more than likely the only way they could get one .

When your talking a mains ac motor i would go with a tested working one ...

[Klaas Robers]

Another question. Where could i buy a motor similar to the original Baird motor? Or would i have to make one myself

I know that Dennis Asseman several years ago found a source of comparable motors. I think they were meant for sewing machines. Old sewing machines have an electric motor fixed against the body of the machine and a loose pedal to control the speed. These motors are comparable to the Baird televisor motor. I think you have to buy an old sewing machine on a flee market, release the motor and discard the sewing machine.
But be carefull. They run directly on the 230V mains voltage......

[McGee2021]

Another question. Where could i buy a motor similar to the original Baird motor? Or would i have to make one myself

I know that Dennis Asseman several years ago found a source of comparable motors. I think they were meant for sewing machines. Old sewing machines have an electric motor fixed against the body of the machine and a loose pedal to control the speed. These motors are comparable to the Baird televisor motor. I think you have to buy an old sewing machine on a flee market, release the motor and discard the sewing machine.
But be carefull. They run directly on the 230V mains voltage......

Most of my projects, with the exception of about 3, have run directly on mains voltage. I have been using mains voltage on my project since i was 5! Thankfully, i havent been electrocuted yet.

[McGee2021]

I was thinking that i could make an electromagnetic sync mechanism. Since the club disk isn't magnetic, i would install magnetic bolts in the sync holes and when a set is in operation, an electromagnet would be mounted somewhere on a TV near the bolts. the electromagnet would be powered by a optoswitch at a transmitting disk

[gary]

I was thinking that i could make an electromagnetic sync mechanism. Since the club disk isn't magnetic, i would install magnetic bolts in the sync holes and when a set is in operation, an electromagnet would be mounted somewhere on a TV near the bolts. the electromagnet would be powered by a optoswitch at a transmitting disk

Yep, it's been done (as has almost everything ) - see the NBTA newsletter collection.

[McGee2021]

I was thinking that i could make an electromagnetic sync mechanism. Since the club disk isn't magnetic, i would install magnetic bolts in the sync holes and when a set is in operation, an electromagnet would be mounted somewhere on a TV near the bolts. the electromagnet would be powered by a optoswitch at a transmitting disk

Yep, it's been done (as has almost everything ) - see the NBTA newsletter collection.

I've just found a tv that uses it. The tv was a, Italian facist, called the Fraccaro 30 line.