Honey extractors RPM

[sherwood]

Has anyone any idea what the rpm of a radial extractor would expect to be. I have been offerred motor and gear box for my extractor. I know its powerful enough to drive my 9 frame radial but am unsure if the rpm is sufficient.

 

[oliver90owner]

What is the gear ratio on your extractor and how fast (what rate) do you turn the handle? Easy to calculate from simple observations.

 

[REDWOOD]

http://www.technologystudent.com/gears1/gears6.htm

 

[sherwood]

Thanks Redwood I was aware of this but am trying to ascertain what the expected revolutions on th the shaft ie the driven wheel you would expect to use on a radail extractor(max) would 120rpm be more than sufficient. I have nothing to go by as I have been given shaft with the brackets attached. I beleive these to be from a Thornes 9 frame extractor in stainless steel. I have sourced a food grade bin, a top bar and bearing and a bottom mounting for the shaft so I am on the final stages of the build.

 

[madasafish]

Anything under 6,000rpm and 100bhp per litre is unacceptable.

Sorry wrong forum..

 

[sherwood]

Anything under 6,000rpm and 100bhp per litre is unacceptable.

Sorry wrong forum..

If you cant make a useful contribution why bother

 

[Beefriendly]

Has anyone any idea what the rpm of a radial extractor would expect to be. I have been offerred motor and gear box for my extractor. I know its powerful enough to drive my 9 frame radial but am unsure if the rpm is sufficient.

Can't really answer what the rpm should be, but there is some information on an old BBKA thread,suggest 100rpm is okay with most electric extractros running at around 2800, no idea if it's accurate.
But it's worth remembering the force exerted on a frame in a centrifuge/extractor is a function of the rotation speed of the centrifuge and the radius of rotation. i.e a bigger extractor with a larger diameter will exert more force on a frame than one running at the same rpm but having a smaller diameter.
The equation is: G-force= 1.12 x R x (RPM/1000)²
where R is the radius of the extractor cage.

 

[wightbees]

Why not use some type of electric speed controller on 230v . I use one on 12v to regulate a water pump so I'm sure there's something out there for 230v , kind of like a dimmer switch. Someone must know what I mean ?

 

[sherwood]

Can't really answer what the rpm should be, but there is some information on an old BBKA thread,suggest 100rpm is okay with most electric extractros running at around 2800, no idea if it's accurate.
But it's worth remembering the force exerted on a frame in a centrifuge/extractor is a function of the rotation speed of the centrifuge and the radius of rotation. i.e a bigger extractor with a larger diameter will exert more force on a frame than one running at the same rpm but having a smaller diameter.
The equation is: G-force= 1.12 x R x (RPM/1000)²
where R is the radius of the extractor cage.

Thanks Bee Friendly but I think that 2800 figure is the raw motor speed before gearing can have been applied. I have found one extractor with the raw speed of 4000rpm with a gearing ratio of 27:1 bringing it down to a maximum rotational speed of 150. What i can not ascertain is whether this maximum speed of 150 would be used or whether the speed regulator would be limited to a far lesser figure. I have no idea what g-force would be needed to effectively throw the wax as well as the honey out of the frame I suspect that the weight of honey may have an effect here as well. ie that is why you start of at a slower speed and having spun out some of the honey you are then able to speed the motor up.

 

[sherwood]

Why not use some type of electric speed controller on 230v . I use one on 12v to regulate a water pump so I'm sure there's something out there for 230v , kind of like a dimmer switch. Someone must know what I mean ?

That is what I intend to do but I am still trying to figure out what the optimal rotation speed is that I am going to need. I dont want to buy a motor and then find that it will not reach this speed

 

[Beefriendly]

. ie that is why you start of at a slower speed and having spun out some of the honey you are then able to speed the motor up.

Tend to start at lower speed as frames have unequal amounts of honey. Once most of that has been spun out extractor stops waltzing around the floor and it's nicely balanced (weight wise)can increase to max to get the last drops out....no idea what rpm mine does

 

[wightbees]

With the controller I have it would work as follows. Regardless of size of motor it would hardly work from turning it on and by continue to rotate dial would increase motor speed. So my thinking is, get a slightly bigger motor and turn dial until your happy with speed on controler. Or am I missing something?

 

[Beefriendly]

Thanks Bee Friendly but I think that 2800 figure is the raw motor speed before gearing can have been applied. I have found one extractor with the raw speed of 4000rpm with a gearing ratio of 27:1 bringing it down to a maximum rotational speed of 150..

If you already know all these speeds I'm puzzled why you are asking us amateurs? Shirley more efficient to ask manufacturers.
You are possibly also missing the bit about the radius of the arm which affects the G force applied on the frame. Hell if you can spin 'em by hand it can't be that fast.....

 

[sherwood]

With the controller I have it would work as follows. Regardless of size of motor it would hardly work from turning it on and by continue to rotate dial would increase motor speed. So my thinking is, get a slightly bigger motor and turn dial until your happy with speed on controler. Or am I missing something?

do you have starting point recommendation then for a motor then if I havent got this how can I decide on a more power one. I am thinking of a motor about 90 -120 watts with a reasonable ammount of torque But WHAT final drive speed should i be going for?????????????

 

[wightbees]

From BBKA site... Hand cranked ones usually seem to be geared around one turn by the operator to three on the cage. One turn per second by the operator seems a comfortable speed so that equates to around 180rpm at the cage.

I'm aiming towards an absolute max of 500rpm on my electric conversion....when I get round to it (and get some honey!

 

[wightbees]

Most honey can be extracted at 90 to 100 rpm. Many modern electric spin at 2800 rpm and the angled drive is a 10:1 ratio. Hence loads of torque and 280 rpm maximum. I normally extract in the low range I mentioned 90 to 120 rpm and as I use a mix of unwired comb this extracts it without many breakages. (1 breakage in over 1000 frames spun this season)

The Karl Fritz instructions say wind the motor up to full 9 (280 rpm) and immediately reduce it back down to 2 (90-100 rpm). This gives the power to overcome the initial inertia. The faster you extract the more wax comb gets broken.

Once some honey has come out of the comb you can increase the speed a little. Of course this is radially. With tangential you have to spin a bit then turn the combs over then spin some more then turn them again.

 

[wightbees]

Not sure if this helps but was from BBKA

 

[Beefriendly]

do you have starting point recommendation then for a motor then if I havent got this how can I decide on a more power one. I am thinking of a motor about 90 -120 watts with a reasonable ammount of torque But WHAT final drive speed should i be going for?????????????

To be honest I'd just go out and buy a commercial firms conversion motor rather than pratting around asking endless questions. How much money do you expect to save by DIY?

 

[Fusion_power]

The extractor should reach a maximum of about 350 rpm. Since it is a radial, it should start about 80 RPM gradually increasing to your chosen maximum. Newly drawn comb is very fragile so it should start slow and gradually increase to a maximum that does not cause the wax to collapse. Be cautious with the rotational speed. Larger extractors have to spin relatively slower. They develop more "centrifugal force" because of the larger diameter. Smaller extractors have to spin a bit faster. I've read that some radial extractors can reach speeds of 500 rpm.

I have and use an old Kelley 4 frame tangential extractor that uses a clutch system to permit gradually increasing speed. I usually run at about 100 rpm for 10 to 20 seconds then increase to the maximum of about 258 rpm. It takes about 60 seconds at max speed to spin out one side of a frame. The motor is 1725 rpm with a 1.5 inch pulley pulling a 5 inch pulley, then through the clutch with a 2.5 inch pulley pulling a 5 inch pulley on top of the extractor shaft.

re centrifugal force, there "ain't no such critter". It is inertial force that affects a rotating object and is directed away from the direction of rotation. Just being a bit pedantic because schools teach this to kids wrong.

 

[oliver90owner]

OK, enough of the guessing.

https://www.thorne.co.uk/index.php?route=product/search&filter_name=gears

Gear ratio 2.5:1 increase. One can turn easily at 60rpm, so 150 at the cage is easy. 100rpm can be sustained for a while, so 250rpm at the cage. Most 9 frame radials have a top speed of about 280-300rpm at the cage. If you don't have it, you can't use it. 80W is the typical standard motor power.

Been discussef on the forum soo many times , over the years....