Sucking disc solenoid?

[Arnak]

Hi Folks,

I recently purchased for ebay a sucking disc solenoid which reputably has a lift capacity of 2.5kg.

It is a 20mm 12V Holding Electromagnet Lift 2.5kg Solenoid
Type: HCNE1-P20/15

It is powered by 12v and has a power rating of 3 Watts.

It can actually manage to lift a 6" rule if you get it near the middle and that is about it's limit.

I am powering it by a 12v 15 watt wall wart, is it a case that there is not enough power from the transformer?

Perhaps the unit is faulty?

Why do they call it a sucking disc solenoid please.

Thanks for any advice.

Martin

 

[PTsideshow]

http://www.made-in-china.com/showroom/wdq7609122/product-detailveGmdshurlcb/China-Sucking-Disc-Type-Electro-Magnets-HCNE1-P-Series-.html

[Arnak]

Hi PT,

Thanks for the link but I'm afraid that still doesn't answer a few of my questions like should it need more power from the wall wart etc.

Martin

[andyf]

If it only requires 3W, a 15W wall wart should be more than adequate to power it. If you have a car and some jump leads, try it on a car battery.

But it may just be a duff Ebay item, in which a different letter should be substituted for the first S in "Sucking solenoid". I've never heard that expression before, but searching on Ebay brings up a few; all from Hong Kong, so something may have been lost in translation. All are 12v, the first allegedly needing 0.2A for 10Kg and the second (from a different seller) 0.2A for 2Kg. Something doesn't sound quite right there. 12V at 0.2A is 2.4 watts, by the way. I'm no expert on electromagnets, but 2 or 3 watts doesn't really seem sufficient to hold 2Kg.

Contact the seller and if necessary start a formal dispute.


Andy

[PTsideshow]

It is some kind of holding electromagentic solenoid, from what little that can be gleaned from the google search for sucking disk solenoid. All seems to be Chinese manufactures web sites or exporters or trade sites but that is the name used must be a very technical term 

[mklotz]

Are you sure you're completing the magnetic circuit?  Try lifting a smooth metal plate with a diameter somewhat larger than the diameter of the solenoid.

[Weston Bye]

Sucking seems to be an Asian equivalent  or characterization for solenoid operation, be it a disk-type or plunger-type  solenoid.  I've seen it on many translated prints (we manufacture solenoids where I work)  A sucking solenoid is what we would call an ordinary pull-type solenoid.  I don't know what they would call a push-type. Spitting?

I've seen the pulling force as well as the stroke distance of the solenoid referred to as suckage.

[PTsideshow]

Sucking seems to be an Asian equivalent  or characterization for solenoid operation, be it a disk-type or plunger-type  solenoid.  I've seen it on many translated prints (we manufacture solenoids where I work)  A sucking solenoid is what we would call an ordinary pull-type solenoid.  I don't know what they would call a push-type. Spitting?

I've seen the pulling force as well as the stroke distance of the solenoid referred to as suckage.

Boy am I good or what "technical term"  the force might refer to the holding and not lifting power. Since the photo's of them appear to have no moving parts in the coil assembly. 

[Arnak]

Hi Guys,

Thank you all very much for the words of wisdom and advice

The circuit is just 2 wires straight to the wall wart so yeah is connected OK.

I agree, I don't see how 3 watts can produce a 2.5kg force.

Happily I only want it to pick up swarf from the mill and the lathe so it only needs to be a bit better than it is.

I'll have to contact the seller and see what he can tell me, it could certainly be faulty.

Martin

[andyf]

Martin,
For swarf pickup, one of these is handy http://mikesworkshop.weebly.com/handy-swarf-pick-up-tool.html .

Mike gave me one, and it's great for cleaning up. Just wave it around over the chips, then hold it over the waste bin and use the screw in the side to pull the magnet away from the end so the junk drops off . No good for non-magnetic stuff, of course.
No wires, batteries or other inconveniences  .

Andy

[Lew_Merrick_PE]

Martin,

1) Commercial electromagnets are measured by lifting essentially pure iron with a machined smooth surface in a fixture that makes intimate contact between the face of the electromagnet and the plate using a load cell to calculate the force.  If the part you are wanting to life is not pure iron (i.e. it is steel with some alloying agents), you will not reach maximum force.  If the part you are wanting to life does not have a perfectly flat and smooth surface, you will not reach maximum force.  This is the first issue.

2) Quite a few vendors of commercial electromagnets lie through their teeth as to the lifting power of their units.

Electromagnets (and other inductors) are all about amp-turns.  At 12V, 3W is (3/12 =) 0.25A (in quick & dirty numbers).  With enough turns, 0.25A is enough to lift a 2.5 kgF (5.5 lb or 24.5 N) load.  Please note the qualifier with enough turns.  The resistance of the magnet wire acts to reduce the active voltage in such a circuit.  The heat generated by the inductor is I²r (I being current, r being resistance).  Balancing these to come up with an "optimum" inductive magnet is no trivial task.

While I am sure that there are good, honest companies in China, my overall experience dealing with Chinese manufacturers is that there is no aspect of design requirements that they will not shortchange upon if they feel they can get away with it (and shave a few more pennies into profit).  Please believe that I can make citations in this regard all day long.  Caveat emptor is the only "rule" many businesses in China regard as functional.

[Arnak]

Hi Andy & Lew,

Andy, thanks very much for the Pick up tool, brilliant.

I will make a couple of those.

Lew, thanks very much for the info, it seems obvious that this magnet must be faulty.
It can only just pick up 6" steel rule if touched in the middle, now that can only be a few grams let alone a KG.

You make some good points regarding the spec of those magnets as well, I don't know about being short a few turns more like a few hundred.

I think that in this case the only sucking bit is me being the sucker who brought it.

Martin

[DavidA]

This may sound a little silly,  but is your rule steel or stainless steel ?

Have you tried to lift other items ?

Dave.

P.s. Don't laugh.  People have been caught out by simpler mistakes before today.

[doubleboost]

When i was at tech classes
We were told sucking was for sex 
In the motor trade we had depresions 
He then said you lot make me depressed
I will never forgett those words of wisdom 
John

[Arnak]

Hi DavidA,

Good thought that but the rule is steel.

I appreciate that mistakes like that are easy to make, that's why I make so many.

I won't make any comments about the sex is for sucking as I'll probably end up getting banned. 

Martin

[Deko]

Hi Martin
             Have a look at Arc Euro's site, i think they have just started selling magnetic swarf picker-uperer's for want of a better name

       Cheers  Derek.

[Arnak]

Hi Derek,

Thanks for the tip, I'll pop over and have a look.

Martin

[hopefuldave]

Ah, I remember that, is it the S.I. or ANSI system that has the Lovelace as the derived unit of suckage?

Dave H. (The other one)

[Arnak]

Hi Andyf,

Thanks to your advice I made a great pickup tool as per that url you supplied.

I brought 10 magnets for about £6 from Ebay, some for other projects.

Having checked out the one from Arc at about £17, a bit too expensive that, I made one in a very short time and can highly recommend that method.

The plastic pipe was a cistern overflow tube, just the right inside diameter for the magnet plus a bit of gaffer tape to close off the end.

Works a treat so I'll probably make another one for the mill and have one for the lathe and mill.

Martin