Homemade clutch

[ronwhite3030]

I was searching for cluthes on google and found how to build one on bee source and thought It deserved to be reposted http://www.beesource.com/forums/archive/index.php/t-224905.html

[BlueBee]

Ron,

That was an interesting post.  The mechanical engineering types always amaze me what they can come up with.  Dealing with the fixed RPM nature of a AC induction motor is definitely a problem.

Have you ever taken apart a snow blower?  The wheel speed control mechanism in a snow blower might be something to consider too.  A snow blower engine is normally run at a fixed high torque RPM to throw the most snow, the designers had to figure out a way to tap off that high RPM to provide variable speed control to the wheels of the snowblower so you can go up and down the driveway at variable speeds.  

In the case of the snow blower, they often use a crude form of a CVT and tap the speed they want from a large rotating wheel attached to the crank.  They use a smaller wheel that moves from the from the ID to the OD of the big wheel to regulate the RPMs on the smaller wheel (which drives the machines wheels).  

I’m not suggesting using a snow blower for an extractor!  I’m suggesting it might be interesting to ponder rather you could implement a similar low cost type of CVT for your AC induction motor to solve all your problems.  That would get rid of pulleys and this clutch.

Trying to think outside the box here  :)

[Acebird]

The simplest clutch you can make is a V-belt but it is not good for extended periods of time because you will have to dissipate a lot of heat.

bluebee the snowblower transmission you speak of would not last at all in a slip situation.  The rubber friction wheel would wear out in no time flat.

Constant slip clutches need to be metal to metal or metal to some kind of friction material like brake lining.  They will need to be massive and have some way to dissipate heat as in a cast fin.

If you are a hobbyist go with a slip belt for soft start if you are not a hobbyist then a variable speed drive of some type is warrented or you need a transmission that will give incremental speeds.  However I can't see you needing more than two speeds (high and low).

[BlueBee]

I agree with you AceBird about the snowblower friction wheels burning up.  Why do you think I had my snowblower apart  :-D

I agree with everything Ace has said.  What I was thinking might work would be to use the AC induction motor as the slipping part in the system.   That’s what AC motors do, they slip back from 60Hz as a load is applied.  The heavier the mechanical load, the more the slippage.  Slippage results in more EMF induction in the rotor, that makes heavier currents, and that generates more torque (up to a point).

Maybe there would be enough slip in the AC motor when starting that the motor would slip instead of the rubber wheels of a snowblower trans slipping?  If a snowblower tranny slips, those little rubber wheels will quickly wear out as Ace says.  So the question becomes would it be possible to design a system where there would never be enough torque to make those rubber wheels slip yet enough torque to get your extractor up to speed?  

OK, how about a new hybrid extractor idea:

Since the AC induction motor is designed to work best as a fixed RPM, how about we gear it down to about 60RPM with a pulley system and connect it to Ron’s extractor unpowered.  Load up his frames and use a hand crank to slowly get the thing up to 40 to 50 RPM.  Then hit a power switch to the AC motor!  The motor then takes over and extracts at 60RPM for as long as you like.  When done, kill the power to the motor and let it spin down on its own.  Reload and repeat.

[rdy-b]

when you extract honey you have to be able to control the speed like a throttle
reason is the balance is always changing with the amount of honey that gets extracted
so you ramp up the speed-sometimes you have to run real slow for a long time till
you find the SWEET SPOT of your balance for a particular load-you have to have the ability to change the speed
and when you change speed you have to be in the power band all the time-cant lose torge- or the weight of a full real of honey will over run the motor with the speed of the real versus the speed of the motor-then the motor frys-thats why controllers will
cut power to the motor on the cheaper ones and on the more expensive ones will act with electric braking -to keep the speed in the desired power curve-RDY-B

[hankdog1]

With an air cooled one i think it would be bulky.  A wet clutch may be a better solution but then you are adding weight.

[Tommyt]

The one in the link above is what I imagine is used in Open faced Fishing reels
when we king fish or tarpon they smoke reels but a high end open reel, using a nylon set of washers holds up OK
 There is no where the amount of time on the reels verse the extractor but IMHO its the same concept

 Here is the diagram of the above post to help see how he made it he has more pic's but I liked this one


Tommyt

[Acebird]

that generates more torque (up to a point).

“up to a point” is a very small range of speed for an AC induction motor unless you have a drive that can vary the Hz/Volts supplied to the motor (inverter drive).

Since the AC induction motor is designed to work best as a fixed RPM, how about we gear it down to about 60RPM with a pulley system and connect it to Ron’s extractor unpowered. Load up his frames and use a hand crank to slowly get the thing up to 40 to 50 RPM. Then hit a power switch to the AC motor! The motor then takes over and extracts at 60RPM for as long as you like. When done, kill the power to the motor and let it spin down on its own. Reload and repeat.

This will work but you have to insure that the crank is removed before you power up or you could get hurt.

when you change speed you have to be in the power band all the time-cant lose torge

I agree with you but for a hobbyist running 2 to 4 medium frames this inertia load is not that great compared to a commercial machine running 10-20 deeps.  The concept of my machine was envisioned by seeing a video of an African using a battery operated drill with essentially a paint mixer bit to spin two frames by hand in a barrel.  You could very easily use Bluebee’s idea and use a variable speed drill as the hand crank to get the extractor going.  Then the motor can be very small because you don’t need a lot of torque to keep it going.  Because of the imbalance problem you do need a slow speed to shed some of the honey from the frames before you increase to the next speed higher.

[Acebird]

Tommyt, just so you have something to think about:

Lets say your extractor need a 1 HP motor to run it at full speed.  If you have a clutch that slips back so it will only go 1/2 speed then that clutch will be burning off 1/2 HP in a constant slip application.  One HP is a small electric burner turned to the 1/2 way mark as a comparison.  You are talking about a lot of heat that you have to dissipate through the clutch (which would be the metal pulley in your diagram).

[Tommyt]

Ace 
 Thats not mine thats from the link up top
I destruct more than invent :-D

Tommyt

[WPG]

simplest clutch...V-belt but...dissipate a lot of heat.

The slippage and heat will degrade the belt and create lots of little beads of rubber that will get down into the honey....ick.

bluebee the snowblower transmission you speak of would not last at all in a slip situation.  The rubber friction wheel would wear out in no time flat.

Wrong. It doesn't have to slip.

Dadant made just that kind of speed control decades ago for all sizes of extractors.
One difference-the large wheel was on the end of the basket shaft.
The small rubber drive wheel moved across the surface of the shaft wheel.

Fill the basket, make sure the adjustment has the drive wheel on the outer edge of the basket disc, start the basket spinning by hand, flip the electric switch, wait a little for the weight to balance and move the lever to push the drive wheel across the flat wheel and gradually increase the speed of the spinning basket.
When it is spinning as fast as you wish leave it to spin until your done, then turn it off and let coast to a stop or use the hand brake.

Parts are still available.
No fancy electronics.

I have an old self-propelled lawn mower with a very similar variable drive. Works great, goes years without parts replacement.


Adapting some snowblower parts may work just great, especially if free!

[Acebird]

Wrong. It doesn't have to slip.

Try using a snow blower transmission for an extractor and let us know how it works for you.

The slippage and heat will degrade the belt and create lots of little beads of rubber that will get down into the honey....ick.

There are billions of riding lawn mowers out in use doing exactly that.  Bringing a blade under a good load up to high speed.  If your drive is below the spinning basket you wouldn't care about transmission dust. ;)

Seriously, if you wanted to make a high production extractor I would start with an automatic washer.  In the spin cycle a cloths washer brings a high inertial load up to speed.  Most machines already have a two speed AC motor, belt drive with intigrated clutch appropriate for like loadings.  Remove the agitator and install a cage to hold the frames and you are good to go.  Depending on the design you may have to remove the pump.  You certainly would have the rinse cycle to automatically clean the basket when you are done.