Governor for homemade generator

[Diy1995]

Just one very small, and perhaps obvious point, the mechanical governor mechanisms and other exposed mechanisms on lawnmower engines tend to attract dust and also dry out. A good clean and a squirt of thin oil works wonders.

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I realised just before that governor is not doing anything at all because load at pulley isn't changing when I put load on motor. Thanks.

 

[Diy1995]

For the same reasons as above you would need to turn the motor at a higher speed tban rated (due to slip) to get the max rated output power from it.
Or accept you'll get around 70% power at 50/60hz.
I found a instructables for a arduino generator controller, it'll give you an idea of whats involved.
https://www.instructables.com/id/Generator-Governor/

I'm ok with 70%. Yes, i would need something like that. But I need actions of servo motor to be based on vac output, not on RPM

 

[Diy1995]

You could use a Picaxe, programmed in the BASIC language, which is the easiest computer language to start with and learn for small projects.
Many on these forums use the Arduino but that uses a variant of the C language which, to me, has an arcane notation that is much more difficult to learn.

You likely will have to add some loop compensation in the control program to achieve a stable generator output voltage (avoid hunting or oscillation in the speed) which will require some form of PID or Fuzzy Logic (which I think is easier to use with a micro).

BASIC language, I know a little bit of this since I used to make simple programs in Visual Basic 6 back in the days (just for fun). PID or fuzzy logic would read my vac voltage? Thanks

 

[crutschow]

PID or fuzzy logic would read my vac voltage?

No, the micro reads DC voltage (rectified from the AC).

PID or Fuzzy Logic are part of the micro control program to provide compensation and obtain a stable control loop.
Without that compensation the engine speed will likely vary and hunt around the desired speed, and not stay at a steady speed with varying load.

 

[tcmtech]

I can't do this because I have 1phase motor. I just realised that angle grinder is doing good even on 300v and 80hz, it's not heating or anything. I will just try to get as close as possible with this design. Thanks

Reread paragraph 4 of that post . Or does you motor somehow not have a start winding and if not why/how?

 

[tcmtech]

I realised just before that governor is not doing anything at all because load at pulley isn't changing when I put load on motor. Thanks.

That makes no sense.

If the engine speed doesn't change when a load is put on it it's doing its job and if it isn't running away when you change the throttle position then it's working the way it's suposed to or the load isn't big enough to make any difference in the engines running speed.

 

[Diy1995]

Reread paragraph 4 of that post . Or does you motor somehow not have a start winding and if not why/how?

Oh, i got confused with something else (c2c design where you have two capacitors on 3ph motor) yes my motor has start winding. I will try it out. So I need to wire capacitor like it was wired in the first place (capacitor from phase to start winding)? Thank you

 

[Diy1995]

No, the micro reads DC voltage (rectified from the AC).

PID or Fuzzy Logic are part of the micro control program to provide compensation and obtain a stable control loop.
Without that compensation the engine speed will likely vary and hunt around the desired speed, and not stay at a steady speed with varying load.

Oh I understand now.
1.I connect transformer and bridge rectifier to vac, transformer must give max output of 5v (or whatever is max rated for microcontroller).
2. I connect vdc from rectifier to microcontroller.
3. I write program for microcontroller and connect servo to it.

Thanks

 

[Diy1995]

That makes no sense.

If the engine speed doesn't change when a load is put on it it's doing its job and if it isn't running away when you change the throttle position then it's working the way it's suposed to or the load isn't big enough to make any difference in the engines running speed.

I'm not sure myself now. I loaded it with 500w angle grinder (i was cutting), and speed didn't change for a bit. Engine is 4hp and motor is 2,2kw. Angle grinder wasn't loosing speed or anything when cutting. I must get more capacitors or higher value one in order to try it with more load (if I try big angle grinder (1000w it spinns a little, than voltage just start's to drop) Thanks

 

[tcmtech]

Oh, i got confused with something else (c2c design where you have two capacitors on 3ph motor) yes my motor has start winding. I will try it out. So I need to wire capacitor like it was wired in the first place (capacitor from phase to start winding)? Thank you

Use the start winding independently as a isolated LC tank circuit No connection between the two is needed for this type of operation.

I'm not sure myself now. I loaded it with 500w angle grinder (i was cutting), and speed didn't change for a bit. Engine is 4hp and motor is 2,2kw. Angle grinder wasn't loosing speed or anything when cutting. I must get more capacitors or higher value one in order to try it with more load (if I try big angle grinder (1000w it spinns a little, than voltage just start's to drop) Thanks

More than likely the 500 watt load is below the engines load sensitivity threshold so it did not need to react to it.

 

[Diy1995]

Use the start winding independently as a isolated LC tank circuit No connection between the two is needed for this type of operation.

More than likely the 500 watt load is below the engines load sensitivity threshold so it did not need to react to it.

I really don't have any idea how to wire this, I have only one wire not used (where start capacitor would be hooked to and other wire of start capacitor would go to phase. Thanks
I will be able to test generator with more load when I will get another capacitor. I'l see how engine will behave.

 

[tcmtech]

The two windings would have to be isolated from each other and the start winding centrifugal disconnect switch by passed so taking the end bell off the back end would be required to get access to the leads where they come out of the windings.

It's pretty easy to do though.

 

[Diy1995]

Hello, I managed to solve the problem with arduino. I wroted code that will do following: when voltage will drop servo will higher the trottle, more capacitors will connect, when voltage will drop servo will lower the trottle, some capacitors will disconect. I also added indicator leds for different voltages. I will open new post about arduinos PSU and overvoltage protection for analog pins. Thank you all for help!