Centrifugal switch ideas please.

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stackerjack

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Hi,
I am building a contraption, powered by a Hot Air engine, which requires a centrifugal switch. The power output is quite low and the switch will be carrying less than one amp.
Does anyone have any ideas for making such a switch please?
It will need to be quite small, and operate at a few hundred RPM max.
Jack
 
Thanks a lot pal. I can use the Normally Closed contact on a micro switch so that when the weights fly outwards, my unit will switch on.
Jack
 
Now the trick is to design the size the balls weight and the spring to operate at the right speed.
Plan for two spring each side of the shaft. You can play with the balls metal Steel versus Aluminum, Copper, Brass. The preload will also affect the switch point.
 
Hi,
Yes, it would matter normally, what sort of metal/springs ets, but on this particular machine, it just needs to operate a relay as soon as it starts.
Thanks for your help.
Jack
 
The only change in the above system I would suggest is to
replace the microswitch
with a rotating magnet and reed switch. No friction . Most hot air,
"Stirling" engines That I have built have no energy to waste.
Reeds are cheap from electronic goldmine, from small to
1 amp capability. Just my 1.414 cents worth.
Perhaps insignificant?
 
I did think of a reed switch, but I don't have any. I have lots of micro switches. Don't forget, as soon as the engine starts, the weights will fly open, releasing the pressure on the micro switch button, so the only friction will be the first second or so that it takes the weights to open.
Good idea anyway............thanks
Jack
 
One consideration, probably not significant for this application:
Micro-switches and even more so Reed switches have Hysteresis, in other words the opening and closing of the contact are at different point of travel.
A plain point contact acting on a leaf spring will have a pretty repeatable operating point.
 
I must admit that I would tend towards an optical interrupter ! No energy loss and accurately definable switching point. Almost certainly salvageable from an old printer. The HP ones had bucket loads in them.
 
That is why you never trow away appliances, you repurpose every component.
Hardware and springs, gears if you are into robotic, lots of DC motors.
 
Repurpose I agree , Where did you get those ball bearings?
Free from 5" & 31/4" floppy drives and hard drives.
Back to opto interrupters, 10ma IR emitter led is not free power,
continuous current!
nor is Bias for the sensing transistor. A reed consumes NO
power while idol. just my 1.414 cents.
 
Thanks for your inputs Guys, but this is not a precise bit of gear being made. It's just a fascinating exercise in playing with hot air engines. It will have no purpose, other than entertainment.
Keep up the good work,
Jack
 
That is almost always the case. Entertainment !
Some get it, some don't. I have a "Ferris? "water wheel
powered by a Denny Hot air pumping engine. In close proximity
to a blown V8 . Guess what gets more attention?
And it is not the Denny.
Dave Sage put a old fashioned ice cream maker on one of his
larger "farm" engines, and powered some things with a generator.
Solving the what does it do question.
I love this hobby, but what does it do?
I really like it when you can do both, techno people are intrigued,
Others Smile! If you get both,, that is what it all about, IMO .
another blablabla from 1.414
 
propclock said:
Repurpose I agree , Where did you get those ball bearings?
Free from 5" & 31/4" floppy drives and hard drives.
Back to opto interrupters, 10ma IR emitter led is not free power,
continuous current!
nor is Bias for the sensing transistor. A reed consumes NO
power while idol. just my 1.414 cents.
Click to expand...

I said nothing about free power !
I said "No energy loss" meaning that it would not absorb any energy from the engine.
I agree that the electronics would require power !
 
How about a Hall effect switch and a small magnet on a centrifugal arm? You'd need a mosfet (or old school transistor and resistor to switch the load, and a dc power supply of course (as you would for the onto)
 
Hi Propclock,
You experience reminds me of a meeting of the Gas Turbine Builders, years ago. Among the exhibits, someone had placed their vacuum flask. It was stainless steel and more or less the shape of a gas turbine engine. It got more attention than any other engine, because people just couldn't fathom out how it would work.
Jack
 
Going thru my plans for certain engines, in this case the R&B engine, this is about the easiest method of getting a centrifugal switch to operate. Whether this can be used for your problem, just have a quickie look and see if something like it will do the job.

12.jpg

13.jpg

I hope this helps

John
 
Ciao test con un tubo rigido di 5mm x10 su un lato mettere 2 contatti distanziati, sigillare il lato dei contatti e poi mettere una sfera di ottone da 3mm per andare avanti e indietro e sigillare l'altra parte secondo il senso di rotazione in una centrifuga la sfera chiuderà il contatto e un test di idee. Antonio Antonio dall'ITALIA.
 
stackerjack said:
Hi,
I am building a contraption, powered by a Hot Air engine, which requires a centrifugal switch. The power output is quite low and the switch will be carrying less than one amp.
Does anyone have any ideas for making such a switch please?
It will need to be quite small, and operate at a few hundred RPM max.
Jack
Click to expand...
 
Antonio said:
Ciao test con un tubo rigido di 5mm x10 su un lato mettere 2 contatti distanziati, sigillare il lato dei contatti e poi mettere una sfera di ottone da 3mm per andare avanti e indietro e sigillare l'altra parte secondo il senso di rotazione in una centrifuga la sfera chiuderà il contatto e un test di idee. Antonio Antonio dall'ITALIA.
Click to expand...

Hi test with a rigid tube of 5mm x10 on one side put 2 spaced contacts, seal the side of the contacts and then put a 3mm brass ball to go back and forth and seal the other part according to the direction of rotation in a centrifuge the sphere will close the contact and a test of ideas. Antonio Antonio from ITALY.
Thanks form Jack
 
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