Extractor motor rpm

[Hivemaker.]

You only need to look back at the pic of the ass Fris put on,very big,but can work at very slow speed,without overheating.

 

[JCBrum]

JCBRUM

What does that mean in plain english?

Induction motors (no brushes, no commutator) normally operate at a fixed speed when run from a domestic mains supply, and are very poor at starting under load on a single phase supply, such as 240v ac in houses.

Motors with brushes and commutators, sometimes called 'universal motors' have a wide capability of speed and load, but require quite a complicated controller sometimes.


I would choose a low cost, variable speed electric drill, say £30, if I were making a home made electric extractor.

Have a look at the pictures on the Fragile-Planet website.

 

[VEG]

Had thought of a drill but want something a bit more permanent with a bit more go. Hence me asking about what motor would suit.

 

[JCBrum]

You don't think it looks to big in the harness then?



Frisbee

Beauty is in the eye of the beholder, and love is blind Fris

 

[JCBrum]

Had thought of a drill but want something a bit more permanent with a bit more go. Hence me asking about what motor would suit.

Something with a gearbox on it, with an output shaft speed which you consider suitable and electric connections which provide a reversing capability, and probably about five inches in diameter.

JC.

 

[oliver90owner]

Manual ones: they say about 100 rpm on the crank handle. Gearing is usually about 2 1/2 to one so speed is about 250 rpm at max. Extraction will be faster at higher speeds but does that matter as long as it extracts? Balance is important or the extractor will try to walk away. As others say, max speed is important or frames may explode.

So take it easy and take your time. An electric motor running for a little while longer is better than winding that handle and sweating cobs!

You can also be doing something else while the motor is doing the job for you - but don't walk away! Organising the next group of frames is time well spent, as there will not be that much time available, but it will reduce the turn-around time and increase the output without all that effort.

Having used a mechanical extractor for the past eight years, I am looking forward to my recent 30 quid acquisition making life easier, next year. That included an old extractor (plastic tank and honey valve have been used elsewhere). The frame was scrapped as it was rusty!

It all comes to those who wait patiently for a good deal - well better than a new one from most of the suppliers! I've been patiently looking for the last six years or so!

Cheap and cheerful brushed motors (rotating armature) usually turn that fast 'cos they are cheap and lightweight; they don't have to. I would think an angle grinder gearbox would be adaptable, but don't go for slow speed, high torque from a small cheap one - it may fail on over-torque. The usual motors are only about 80 watts, I believe.

Regards, RAB

 

[JCBrum]

Angle grinders usually go at about 3000 rpm, which is too fast and are not variable speed.

 

[OXFORDBEE]

What about a 3 phase motor?

 

[JCBrum]

3-phase motors are perfect ! ..........

...... IF, you've got a 3-phase electricity supply, ......

 

[roche]

Speed control is a bit of a problem though - need an inverter....

 

[oliver90owner]

need an inverter....

Usually a frequency converter....

Armature/brush motors will work on A?C or D/C and are voltage-speed related. Induction motors are frequency-speed related.

Regards, RAB

Regards, RAB

 

[GingerNut]

Bit of a stutter there RAB

 

[wbchive]

The sky's the limit. You could get a Rover 3.5 litre V8 with an automatic gearbox and you'd have power and variable speed control. I'd go with a decent electric drill though. It's easy to connect to the top of a shaft, it's got plenty of torque and it's variable speed. It may even have reverse, although I can't work out how this would be useful. Speed can be your enemy when extracting. It's better to work at a slower speed for a longer time if you want to preserve the comb.

Steve J

 

[plumber]

motors and gearboxes

had a quick trawl of the flea bay

http://cgi.ebay.co.uk/NEW-24V-DC-MO...s_ET?hash=item3ef7c3c45d&_trksid=p3286.c0.m14

http://cgi.ebay.co.uk/Electric-moto...s_ET?hash=item27ab98fa15&_trksid=p3286.c0.m14

gives an idea of what you could use just gota find the one

 

[JCBrum]

Speed control is a bit of a problem though - need an inverter....

This observation is not a specific characteristic of three phase motors.

3-phase motors can be any type already discussed, but it is unusual to find any that are not induction motors.

The observation is however a characteristic of induction motors in general, including single phase ones.

The use of an inverter to provide speed control by variable frequency is just as applicable whether the induction motor is single or three-phase, and can significantly increase the cost of the installation.

If one did decide to use an inverter for speed control, then there would be little point in choosing anything other than a three phase induction motor ........

Because 3-phase induction motors are self-starting and single phase induction motors are not.

Single phase induction motors are made self starting by an auxiliary starting circuit which simulates 2 or 3 phase conditions for a few seconds, and then automatically disconnects when rotation commences. Usually 2-phase simulation occurs.

The use of an auxiliary starting circuit usually means the starting torque is very poor, but in the case of a honey extractor, the starting torque requirement is also low. If it were otherwise, it would be best to use a separate clutch with a single phase induction motor, and engage the drive only after the motor had started, and developed its full torque.

This is getting more complex than the OP envisaged, I recommend simplicity.

JC.

 

[JCBrum]

had a quick trawl of the flea bay

http://cgi.ebay.co.uk/NEW-24V-DC-MO...s_ET?hash=item3ef7c3c45d&_trksid=p3286.c0.m14

http://cgi.ebay.co.uk/Electric-moto...s_ET?hash=item27ab98fa15&_trksid=p3286.c0.m14

gives an idea of what you could use just gota find the one

Of the two choices offered, the first one is too small and too slow.

The second one is also a bit small, but is too fast, necessitating a further speed reduction of about 2.5:1. The gears usually fitted to a hand powered extractor give a speed increase of approx 2.5:1, which of course is the opposite of what that motor might require.

 

[JCBrum]

It may even have reverse, although I can't work out how this would be useful.
Steve J

When a radial extractor is running the frames tend to 'flop' slightly to one side, opposing the direction of rotation.

This means honey is extracted more completely from one side of the comb than the other.

Reversing the direction makes the frames flop the other way and so ensures complete extraction from both sides.

In some tangential extractors, reversing them makes the frames swing around through 180 deg. so presenting the second side for extraction.

 

[OXFORDBEE]

I've got a 3 phase motor and a GEC VAT20 inverter on my extractor...

 

[JCBrum]

I've got a 3 phase motor and a GEC VAT20 inverter on my extractor...

I bet it's not as pretty as Fris's Ass

 

[VEG]

oxfordbee what size motor did you use?
How is it fitted to the basket shaft direct? or pulleys