Hi everyone, I am in the process of making a new 18 frame radial honey extractor. My abilities stop when it comes to electrics.
This is what I would like to do if anyone can help me with a setup that would be awesome.
I need a motor that can gradually spin, slow to start then speed up as the load starts to lighten. Max weight would be approx 50kg at the start and max rpm would be about 180 to 200 at the end.
it would be awesome if it could be programmed to work through say a 5 min cycle. alternatively a dial that I can adjust over the 5 mins would work to.
thanks heaps Drew
Can you explain the reason for variable speed?
Just curious as it adds to the complexity.
Will this be ac mains powered or battery?
I’ve seen clothes dryers used as centrifugal devices in other industries.
Constant torque will accelerate much like you describe. Decel might be natural after removing power.
Thanks Inow, the reason is if it spins too fast at the start the wax will collapse under the weight of honey so a slow start gives it a bit a time for some honey/weight to come out of the frames and finishes faster to remove as much as possible.
It will be 240 power.
here is a pic of a commercial 1, not sure if that’s helpful?
That makes sense.
Easy peasy!
Just buy a cheap chinese vfd. Check the specs first for maximum ramp rate.
A Toshiba that I just looked at was 600 seconds. Program it for 5 minute ramp up and 5 minute ramp down.
Connect a bath fan timer to the “run” terminals.
It will ramp up for the set time. Run for the fan timer setting. Then ramp down at the set rate
Up and down ramps can be different.
A .4 kw vfd will run a 1/2hp motor. A 1kw is not much more money and will control larger than a1 hp motor.
Should be less than $100
For those in USA. A vfd will run a 240v 3 phase ac motor on 120v household power.
Can you see the hp and gear ratio?
I wish? I will do some googling to work out what you have said earlier 
can you add some links to the items you have mentioned?
Also can I just connect a motor directly to it and let the vrd control the speed or do I need to find a motor gearbox setup?
You will need some type of reduction. Best to just find a 90 deg gear motor.
Slowest ac motor is 1800 rpm. 5:1 is a good place to start.
The closest you can match maximum motor speed to what you need the better.
The vfd will overspeed the motor if needed.
Righto I think I’m pickin up what your puttin down. I’m not 100% sure what the bath fan is for?
is it ok if I find some part and list them up here for confirmation that I going to get the right stuff?
This example is 700rpm Only .16 hp though
VFD example unknown specs
And a timer
So the fan switch simply cuts power after set time?
No, it turns of the vfd. Then the vfd ramps down to zero.
Motor would work for manual operation, not with a vfd.
If it’s powerful enough.
You need a simple 3 phase motor to use the ramp function of speed control.
You would need the manual to see if it will ramp up and down at the rate needed.
I don’t have 3 phase power though?
That’s one of the things the vfd does.
Connect 1 phase to input.
Connect 3 phase to motor.
Connect timer to vfd on/off terminals.
That’s It!
Set maximum speed of motor.
Set to ramp up over 5 minute period.
Set to ramp down over x minute period.
To start cycle. Set timer to total run time less ramp down time.
Spin cycle will start at 0 rpm when timer is turned.
Ramp up for 5 minutes.
Run at full speed until timer runs out.
Ramp down to 0 rpm at the ramp down rate.
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Ask 2 things before buying.
Will it work with single phase input?
Can ramp up be set to 5 minutes?
would these 2 work together?
Yes, but you need to ask the questions mentioned above.