motor speed ( following all my motors question)

[audioguru]

In the schematic Andy provided Pulse Width Modulation 2
R2 is 120R 0.25W 10% or better. I don' t have that. Can I use a "normal resistor"? Which value then?

Also, I don't have mylar film or ceramic caps, can I use electrolytic instead?

R2 is an ordinary 120 ohm 10% or better (use 5%) 1/4W resistor. They are available almost anywhere (except RadioCrap).
Mylar film, poly film and ceramic capacitors are available almost anywhere (except ...).

 

[saturn1bguy]

the link you posted has given me a step to the right direction.

My doc will help you with basic H-Bridge, PWM, and motor control understanding, but doesn't address DCC at all. I'm just saying...

 

[blueroomelectronics]

I wonder if the OP understands this project requires a microcontroller, the ppt presentation used both PICs and AVRs (and also used a stepper motor).
A 555 is not needed for DCC.

 

[jacks]

Hi friends

I have built the 2nd circuit from the bottom and its working well except I applied a TTL via Function generator. I applied the TTL on one of the strobe and I am not getting any turn on the motor though I can measure the same voltage across the collectors. The idea was to get the motor spinning faster by varying the width of the modulation. Now if I connect the strobe to a high it spins constantly. I am trying to test PWM via function generator and no luck. Am I doing it correctly?

Jacks

 

[blueroomelectronics]

Jacks why not start your own thread, the OP wants PWM you want DCC.

 

[jacks]

Jacks why not start your own thread, the OP wants PWM you want DCC.

OK I will start my own thread. Thanks

Jacks

 

[poutpout]

Hi!
So... I have built this PWM tutorial I have change de values of both caps to stop hearing the frequency.

But ...
I understand now that what I want is a motor turning for a regularly 3 RPM or a for a max of 6 RPM. I have tried changing the value of the pot, resistors, etc... can't get that. Any suggestion?

 

[audioguru]

When you turn the pot, does your motor speed up and slow down?
If the max speed of the motor is 10,000RPM then the minimum speed is 5% which is 500RPM.

You want a speed that is too slow.

 

[poutpout]

When you turn the pot, does your motor speed up and slow down?

Yup!

If the max speed of the motor is 10,000RPM then the minimum speed is 5% which is 500RPM.

Mmmmmm.... I think you are right! I have somes different models and just looked rapidly over the net and they are like 7000RPM more or less.

I'm getting discouraged... It is hard to find because normaly when people buy motors, they want them strong and fast, that's not what I want. Is there a place where I can by "slow" motors? cheap cheap cheap?

 

[Leftyretro]

Yup!

Mmmmmm.... I think you are right! I have somes different models and just looked rapidly over the net and they are like 7000RPM more or less.

I'm getting discouraged... It is hard to find because normaly when people buy motors, they want them strong and fast, that's not what I want. Is there a place where I can by "slow" motors? cheap cheap cheap?

No, you've been told several times that small DC motors are not designed to directly run at such low RPMs. You need to have gear reduction to use such motors. Most applications for such a low speed will use a stepper motor and digital controls to set the speed.

 

[audioguru]

Slow motors have gears or pulleys to slow them without losing all the torque.
I have an electric motor on my model airplane that has 24:1 gears. The motor spins at 8000RPM and the propeller spins at "only" 333 RPM.

 

[poutpout]

No, you've been told several times that small DC motors are not designed to directly run at such low RPMs. You need to have gear reduction to use such motors. Most applications for such a low speed will use a stepper motor and digital controls to set the speed.

I'm sorry, I'm learning. It's all new to me.

Now... gear reduction or pulleys... ok, I got it!

... and thanks all for your replies, I think you are all great and very patient!
Thanks a lot!

 

[poutpout]

Hi there!

Thanks again, everything works like a charm since I use gears!
Now my second step would be... Timer

Is there a way to add a timer in my 555 circuit PWM tutorial.
For an example, I'd like the motor turn for 10 sec - stop 5 sec - start and turn 1 min - stop 15 sec ...

 

[Ubergeek63]

Hi there!

Thanks again, everything works like a charm since I use gears!
Now my second step would be... Timer

Is there a way to add a timer in my 555 circuit PWM tutorial.
For an example, I'd like the motor turn for 10 sec - stop 5 sec - start and turn 1 min - stop 15 sec ...

that seems a bit complicated for a simple timer. You will want to graduate to a micro for that one.

If you have a limited amount of steps in the cycle it is possible to use a timer and a counter to switch in different timing resistors for each step, but you are adding a FET and a resistor for each step.

Dan

 

[poutpout]

that seems a bit complicated for a simple timer.

Oh no. This is the circuit I use for controlling the speed of the motor.

 

[blueroomelectronics]

Hi there!

Thanks again, everything works like a charm since I use gears!
Now my second step would be... Timer

Is there a way to add a timer in my 555 circuit PWM tutorial.
For an example, I'd like the motor turn for 10 sec - stop 5 sec - start and turn 1 min - stop 15 sec ...

Of course a microcontroller could do this. Having multiple and different on/off times

 

[poutpout]

Of course a microcontroller could do this. Having multiple and different on/off times

Yes, but I guess it's not possible without a microcontroller?

 

[Ubergeek63]

Yes, but I guess it's not possible without a microcontroller?

Again: how many different states in the cycle are there? You only mention four. You can put in a different timing resistor for each state selected by a counter as I said before.

 

[poutpout]

Again: how many different states in the cycle are there? You only mention four. You can put in a different timing resistor for each state selected by a counter as I said before.

I'm sorry, it is just because I don't understand what you mean. You said I only mention four and I don't see where I said that?

 

[blueroomelectronics]

I'd like the motor turn for 10 sec - stop 5 sec - start and turn 1 min - stop 15 sec ...

Is that the entire sequence? Is there more?