Author Topic: Question! and Help I need to build a v8 engine servo motor governor (Read 23612 times)

wheelyneil · « **on:** September 14, 2009, 08:38:05 PM »

http://www.youtube.com/user/roadrambler4u#play/all/uploads-all/0/q4WPnyejodU

Hello All

I am New here but I thought it would be a good place to start.

In the video the engine will be hooked to a generator. I need to maintain 1200 rpm's all the time. Can anyone share a Circuit that I could build to run a servo to control the speed.

I have a Futaba s3003 servo and was trying to build a circuit with a voltage divider and 555 timer but it just was not stable.
and I know just enough about robots and electronics to know that if you see smoke it's toooooooo late....

$:-\$ :'(

Anyways anyone that would care to to give me a shout out and help would be great.

take care all
wheelyneil

madsci1016 · « **Reply #1 on:** September 14, 2009, 09:33:50 PM »

First, why 1200 rpm's? If you are building a generator, you need it to run at 1800 rpm (for 60 Hz) or 1500 (for 50 Hz), so how are you getting 1200?

Second, any speed controller will have to have feedback from the engine on how fast it is spinning. As you add electrical load, the engine will start to slow down, the servo will have to move to allow more throttle. How is it going to know the engine is slowing down? Answer me this and i will see if i can help.

wheelyneil · « **Reply #2 on:** September 14, 2009, 10:12:02 PM »

Hello and thanks for responding,

First off I live in the USA our electric is on 60hz -my gen is 6 pole and needs 1200 rpm to hold 240vac.

the circuit I was working on was pluged into the gen output of 120vac. Then rectified to pulse 5v dc then filtered with a cap 1uf then this voltage was hooked up to a 555 timer circuit with my signal volts adjusted to 1.6v reference for servo motor to nutrual position.

When load changes or rpm goes up or down the circuit was supposed to drive the servo so it would increase and decrease carbi.

Thats about as easy as I can explain. But just couldnt get it stable it was all over the place moving the servo arm.

Thanks
Neil

Soeren · « **Reply #3 on:** September 15, 2009, 01:05:09 PM »

Hi,

Quote from: wheelyneil on September 14, 2009, 10:12:02 PM

[...] needs 1200 rpm to hold 240vac.

the circuit I was working on was pluged into the gen output of 120vac.

Are we talking 240V or 120V?

Quote from: wheelyneil on September 14, 2009, 10:12:02 PM

Then rectified to pulse 5v dc then filtered with a cap 1uf then this voltage was hooked up to a 555 timer circuit with my signal volts adjusted to 1.6v reference for servo motor to nutrual position.

When load changes or rpm goes up or down the circuit was supposed to drive the servo so it would increase and decrease carbi.

Thats about as easy as I can explain. But just couldnt get it stable it was all over the place moving the servo arm.

Either the sensing was erratic (due to noise and transients), or perhaps the regulation loop was continuously overshooting - probably a bit of each.

For the speed sensing
You could either tap the generator for a signal, take it through a voltage divider and then through a pulse former to get a clean and predictable pulse train at the frequency of the generator.
Or...
Make an infrared sensor to read a disk (or the pulley in front) painted with black and white sections.

When you have the pulses proportional to engine speed, you can either use them like that using a microcontroller or you can integrate the signal to get a signal for an analog circuit.

Then drive the servo, a DC motor or whatever with a circuit that regulates relative to the error signal (i.e. the absolute difference between the wanted speed and the instantaneous speed, like the "P" (for proportional) in a PID control, or something similar. IOW, if the difference is large, a large regulation is in order, when the difference is small, the regulation must be small as well.

Hope this makes sense to you.

wheelyneil · « **Reply #4 on:** September 15, 2009, 02:41:29 PM »

Quote from: Soeren on September 15, 2009, 01:05:09 PM

Hi,

Quote from: wheelyneil on September 14, 2009, 10:12:02 PM
[...] needs 1200 rpm to hold 240vac.

the circuit I was working on was plug ed into the gen output of 120vac.
Are we talking 240V or 120V?

240v max output

but using 120v for circuit Vcc down to 5 vdc

Quote from: wheelyneil on September 14, 2009, 10:12:02 PM
Then rectified to pulse 5v dc then filtered with a cap 1uf then this voltage was hooked up to a 555 timer circuit with my signal volts adjusted to 1.6v reference for servo motor to nutrual position.

When load changes or rpm goes up or down the circuit was supposed to drive the servo so it would increase and decrease carbi.

Thats about as easy as I can explain. But just couldn't get it stable it was all over the place moving the servo arm.
Either the sensing was erratic (due to noise and transients), or perhaps the regulation loop was continuously overshooting - probably a bit of each.

For the speed sensing
You could either tap the generator for a signal, take it through a voltage divider and then through a pulse former to get a clean and predictable pulse train at the frequency of the generator.
Or...
Make an infrared sensor to read a disk (or the pulley in front) painted with black and white sections.

When you have the pulses proportional to engine speed, you can either use them like that using a microcontroller or you can integrate the signal to get a signal for an analog circuit.

Then drive the servo, a DC motor or whatever with a circuit that regulates relative to the error signal (i.e. the absolute difference between the wanted speed and the instantaneous speed, like the "P" (for proportional) in a PID control, or something similar. IOW, if the difference is large, a large regulation is in order, when the difference is small, the regulation must be small as well.

Hope this makes sense to you.

Yes it does make sense the only thing is I am very limited on on electronics and micro controls.

Could you direct me to a diagram or circuit drawing that I could use.
I like both your ideas.

Thanks for your input
anyone please send me to find a good stable circuit to servo contoll this engine I really need help with this.

thanks so much.

Neil

madsci1016 · « **Reply #5 on:** September 15, 2009, 10:12:52 PM »

Quote from: wheelyneil on September 14, 2009, 10:12:02 PM

Hello and thanks for responding,

First off I live in the USA our electric is on 60hz -my gen is 6 pole and needs 1200 rpm to hold 240vac.

the circuit I was working on was pluged into the gen output of 120vac. Then rectified to pulse 5v dc then filtered with a cap 1uf then this voltage was hooked up to a 555 timer circuit with my signal volts adjusted to 1.6v reference for servo motor to nutrual position.

When load changes or rpm goes up or down the circuit was supposed to drive the servo so it would increase and decrease carbi.

Thats about as easy as I can explain. But just couldnt get it stable it was all over the place moving the servo arm.

Thanks
Neil

This kind of control would not work for a number of reasons, the first being that speed of generator is not directly proportional to output voltage ( i'm assuming this is what your circuit was comparing, you were not clear). Also, if you electrical end has a voltage regulator, it would try to adjust voltage on it's own, and they fact that it is trying to fix voltage and your servo is trying to correct it as well could be causing issues.

I am surprised that you are using a 6 pole end, these are rare as many engines have low efficiency at that speed. Have you looked at your engines efficiency or power versus rpm graph? Professionally built generators usually run at 1800 rpm for Diesel and 3600 rpm for gasoline / natural gas as those are near the engines sweet spot in output power.

I can't think of a way to do it easily without a micro-controller. (maybe mechanically using a vacuum hose from your intake system; as the engine slows down, vacuum pressure drops, so have the drop in pressure result in a increase of throttle. )

You could look at this project, http://www.ikalogic.com/d_tach.php , change it a bit to operate a servo instead.

Disclaimer: My family owns and operates a generator sales and service business. I grew up working on generators.

wheelyneil · « **Reply #6 on:** September 15, 2009, 10:40:28 PM »

Thank you for the info I think that a hall effect circuit could do it. I just want the circuit to hold the RPM as close and as fast as it can. Here is a link that shows my engine and genhead that is run off a wood gasifier.

http://picasaweb.google.com/neilball34606/DropBox?authkey=Gv1sRgCPDd3JifvqaRPw&pli=1&gsessionid=xmlcgk76ZzgOzzI0uUcwYA#

I just want to hold 1200 rpm the best I can with this genset without pulley control. I know a servo controlled circuit can do it!

Hey thanks so much for your help.

any more input would be welcome

Neil

Daanii · « **Reply #7 on:** September 16, 2009, 10:55:08 AM »

A Hall-effect sensor will let you find the revolutions per minute. But I don't think you can do what you want to do with an analog circuit. As MadSci says, you really need a microcontroller to do the calculating and drive your servo motor. That means writing some software. Can you handle that? Or is that why you're looking for an analog circuit?

Soeren · « **Reply #8 on:** September 16, 2009, 03:40:47 PM »

Hi,

Oh please... This is as easy (or hard, whatever your bias) to do in analog as it is in digital.
A Hall sensor is just fine for picking up engine RPM.
I'll look into it tomorrow - it's bedtime here.

wheelyneil · « **Reply #9 on:** September 16, 2009, 04:24:26 PM »

Hello and thanks for the help.
Let me clear a couple things up.

1 I need to maintain 1200 rpm's with my engine.
2.I want to use a electronic type control with a servo to hold engine speed.
3 The Alternator has a Voltage regulator to help stabilize output when rpm's change.
4 I need the help of people that have way more know how then I have.
5 I have some knowledge of basic electronics but thats all.
6 I don't know how to code or write software.
7 I really would like to use a microcontroller and servo but any circuit that will get the job done with a servo futaba s3003 will work.
8 I do understand that a hall effect sensor circuit uses the magnetic pickup to send a signal, but where it sends it and how to make a servo do it's thing I'm clueless.
9 I am looking for the easiest way -- be it digital or analog.

10 AND MOST OF ALL PLEASE EXPLAIN THINGS LIKE I KNOW NOTHING WHICH IS JUST ABOUT TRUE WHEN IT COMES TO ROBOTICS AND CONTROLLERS AND SUCH.

Thanks so much for all the input and help.
And I am watching and trying to learn.

Take care
Neil

kd5kfl · « **Reply #10 on:** September 16, 2009, 06:19:33 PM »

what you are designing is a closed loop servo

what you need is a phase locked loop

the frequency source would be the ignition pulses of the engine, or a clear wheel with evenly spaced stripes interrupting a photo sensor, or a solid wheel with evenly spaced holes illuminating a photo sensor, or...

the DC output would feed a linear actuator or RC servo.

no, I won't hold your hand and step you through this process.

there is a a commercial product which does this. it's called a cruise control. available at any junkyard.

wheelyneil · « **Reply #11 on:** September 16, 2009, 07:02:24 PM »

Hello and thank you!

I hope I have not made anyone mad and I know there are cruise controls at the junk yard.

I was trying to see if there is a circuit that anyone could make at home.
Sorry if I am so far below you in electronic know how.

and I wouldnt hold your hand , unless your a lady?

I'm just asking questions and learning a little.

Peace

Daanii · « **Reply #12 on:** September 16, 2009, 07:27:27 PM »

As I am sure you are learning, this forum can be an unfriendly place.

Good luck with your project. I looked at the video and pictures. Looks interesting.

wheelyneil · « **Reply #13 on:** September 17, 2009, 10:36:54 AM »

Quote from: Daanii on September 16, 2009, 07:27:27 PM

As I am sure you are learning, this forum can be an unfriendly place.

Good luck with your project. I looked at the video and pictures. looks interesting.

Thanks Daanii

You know I have studied Basic electronics, but no education in controllers micro chip coding.

Why do so many people look down their nose if you are trying to learn.

Anyways thanks for your support.

Take care
Neil

Soeren · « **Reply #14 on:** September 17, 2009, 11:08:28 AM »

Hi,

Does your motor have a magnetic pick-up (Hall switch) allready?
If so, it is possible to tap the signal from that.

A Hall switch can also be used (with a biasing magnet) to tap a signal of a much higher frequency from a cog wheel or similar if one is reachable and you can mount it in a stable and safe way.

Perhaps a Hall pick-up from the junkyard could be adapted easily, as it has got mounting holes and it's made for a rugged environment, so should be a good choice.

wheelyneil · « **Reply #15 on:** September 17, 2009, 11:49:30 AM »

Quote from: Soeren on September 17, 2009, 11:08:28 AM

Hi,

Does your motor have a magnetic pick-up (Hall switch) allready?
If so, it is possible to tap the signal from that.

It does have a hall effect ignition just like the picture here.

wheelyneil · « **Reply #16 on:** September 18, 2009, 04:43:47 PM »

Okay here is the question.

Is there a hall effect PLL servo controll circuit that anyone knows of ?

I would think that one of the robot guys could come up with something to govern a V8 engine that anyone could build at home.

Just a little servo moving back and forth holding a rpm.

I don't know but asking again.

please don't take offence to this post please I'm trying to find away to do this in a circuit that would be open source for all to have.

regards wheelyneil

Daanii · « **Reply #17 on:** September 18, 2009, 05:39:09 PM »

Quote from: wheelyneil on September 18, 2009, 04:43:47 PM

I would think that one of the robot guys could come up with something to govern a V8 engine that anyone could build at home.

The problem is, there is no simple circuit to do what you want. You are right that solving the problem is not very hard. But you need some basic skills to figure out how to do it, and you then need to spend some time doing it. That's why you are not getting the response you want here.

It's like this. Take the engine you repaired for your project. I could buy a broken engine like that, and then ask you to tell me how to fix it. But you could not help me much. I don't have the tools, or the knowledge, to make use of what you tell me.

That's what kd5kfl was getting at. As he says, a cruise control comes closest to what you want to do. But it's not close enough that anyone could just give you instructions on how to use it to do what you want. Other solutions will probably be even harder.

In my opinion, that's no excuse for snotty comments. Still, I think that's the reason why you aren't getting what you want.

Soeren · « **Reply #18 on:** September 18, 2009, 07:24:50 PM »

Hi,

Take a look at this: http://That.Homepage.dk/PDF/Speed_Governor.pdf and tell me if you are able to build this.

wheelyneil · « **Reply #19 on:** September 19, 2009, 11:40:25 AM »

OMG thank you so much.

Sorren if this takes care of what I am trying to do? I will scream --HE'S THE MAN!!!!!!!!!!!!

This is all I wanted was a circuit I could build and try to make it work.

I will proto it up on a board and see what I get.

I understand why it is hard for some to respond and help me. But building a circuit and really understanding what is happening in it is very different.

As I build I can look at each componet and read what its is doing then as I move through the diagram hopfully I will learn tons of info.

I think this is how many learn. You can have theory but building it helps me much more.

I may get it write and have some problems along the way, but if the circuit is acting up then I could come ask opinions on it.

Hey I Just wanted to say thanks and hope I didn't offend any one.

Neil

wheelyneil · « **Reply #20 on:** September 19, 2009, 11:47:15 AM »

Soeren sorry for the Misspelled name.

I was just over wellmed to see what may be my answer.

Thanks so much!

Neil

kd5kfl · « **Reply #21 on:** September 19, 2009, 11:52:48 AM »

it wasn't a snotty comment, it was experience. way too many people want you to design a 30 node wirelress mesh with a RADIUS server and VPN and can you have that by noon, I'm kinda busy here. just nip that in the bud.

wheelyneil · « **Reply #22 on:** September 19, 2009, 12:12:28 PM »

Quote from: Soeren on September 18, 2009, 07:24:50 PM

Hi,

Take a look at this: http://That.Homepage.dk/PDF/Speed_Governor.pdf and tell me if you are able to build this.

Hello again I guess I should have looked closer at the circuit. Do you have the missing values for some of the resistors and caps and op amps ECT?

Thanks
Neil

wheelyneil · « **Reply #23 on:** September 19, 2009, 12:25:54 PM »

Quote from: kd5kfl on September 19, 2009, 11:52:48 AM

it wasn't a snotty comment, it was experience. way too many people want you to design a 30 node wirelress mesh with a RADIUS server and VPN and can you have that by noon, I'm kinda busy here. just nip that in the bud.

Hello kd5kfl

No probs here man thank you for your suggestion.

If you notice I asked about the pll circuit with a Hall trigger back a few posts ago.

But having a circuit to work on is really what I wanted.

Hopfully I can get it done with everyones suggestions.

Peace.

Neil

Soeren · « **Reply #24 on:** September 19, 2009, 03:43:30 PM »

Hi,

Quote from: wheelyneil on September 19, 2009, 12:12:28 PM

[..] I guess I should have looked closer at the circuit. Do you have the missing values for some of the resistors and caps and op amps ECT?

It isn't a done and ready circuit (yet), I just posted it to hear if you are up to building something like this (if you aren't, there's no use in spending more time on it).
What I did made so far (when I posted it) is not calculated for the voltages I assume and smaller changes should be made, but it will be about the same level of complication.

A couple of questions that I need answered to finish the circuit:
- Can you work from a schematic?
- Can you make a PCB if you have the design?
- Do you have the battery charged from a generator on the motor via a charge controller?
- Do you have a DMM?
- Do you have access to an oscilloscope?
- What magnitude of voltage does the Hall device give (5V/12V/Other)?
- Do you perhaps know the output impedance of the Hall device?
- Are you prepared on a bit of prototype development (where I guide you and you do the measurements)?

wheelyneil · « **Reply #25 on:** September 19, 2009, 05:48:30 PM »

A couple of questions that I need answered to finish the circuit:
- Can you work from a schematic?--------yes

- Can you make a PCB if you have the design?-----I have never done it! But photo etching a plate I would give it a whirl!

- Do you have the battery charged from a generator on the motor via a charge controller?--Yes via normal altantor on the v8

- Do you have a DMM?-----Yes

- Do you have access to an oscilloscope? NO! Am trying to get one local above 20 mhz and I really need to see the signals.

- What magnitude of voltage does the Hall device give (5V/12V/Other)? I was waiting to buy one to fit spec's on desighn.

- Do you perhaps know the output impedance of the Hall device? Not until I get what the circuit needs

- Are you prepared on a bit of prototype development (where I guide you and you do the measurements)?

wheelyneil · « **Reply #26 on:** September 19, 2009, 05:51:03 PM »

ooops missed one

- Are you prepared on a bit of prototype development (where I guide you and you do the measurements)? yes what ever is needed.

Thanks Again

Neil

wheelyneil · « **Reply #27 on:** September 19, 2009, 06:15:10 PM »

Soeren
I wanted to get back with you about the questions on the hall effect switch sensor. I was confused and wasn't sure if you are wanting to use the signal From the current ignition used.

Sorry for the mix up!

If you are asking about the one being used in the distributor as the reference signal that is used for the ignition that is on the engine now? --------No I don't have manufacture specs on it for you. And not sure if I can find them.

But I will try!

Thanks
Neil

Soeren · « **Reply #28 on:** September 19, 2009, 07:16:43 PM »

Hi,

Quote from: wheelyneil on September 19, 2009, 05:48:30 PM

- What magnitude of voltage does the Hall device give (5V/12V/Other)? I was waiting to buy one to fit spec's on desighn.

To cut through any doubts, I'm talking about the one in the distributor. With a Hall allready there, it would be crazy not to take advantage of it, since it's allready sitting there in a safe and sound way.

Of the two cables going from the distributor to the electronics box, one will likely be connected to either ground or B+ with the other carrying the Hall signal.
It's this signal that can be used, but you need to know what the other wire is connected to (B-, B+ or some intermediate). That should be easy to find out with your DMM (set to DC, 20V range), as well as finding out the approximate amplitude of the signal (with the DMM set to AC on the 20V range).
In both instances, use the black lead connected to the motor body and probe with the red lead.

I assume one wire is grounded (through the electronics box perhaps) and the other wire to carry a signal of 5V peak.
http://www.boatfix.com/merc/Techbk/94/94hg4b.pdf page 6, item #11, the two terminals with screws facing outwards through the distributor body.

However it's made and is working, it can be used as the sensor for the servo controller (while still fullfilling its intended job) and you have the added safety in the fact that, if the motor's running, the speed governor will get its pulses as well. It is simply a matter of designing the input side for this.

wheelyneil · « **Reply #29 on:** September 20, 2009, 09:18:36 AM »

Hello Soeren

I will check on the connection out of the distributor. And let you know, and will check voltages and magnitude with DMM. Thanks!

Neil

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Author Topic: Question! and Help I need to build a v8 engine servo motor governor (Read 23612 times)

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