Electro scrap magnet

[Mogman]

I have acquired an electro magnet and would like to know what voltage it requires there must be a calculation for it
now my other one runs of a 220 volt 7kw dc generator that is on my duck but would like one on the tracked machine but this one is way smaller and came off a crusher bucket so I’m thinking it may just run from the machine batteries (24v)

thoughts please

 

[Lancs Lad]

I have acquired an electro magnet and would like to know what voltage it requires there must be a calculation for it
now my other one runs of a 220 volt 7kw dc generator that is on my duck but would like one on the tracked machine but this one is way smaller and came off a crusher bucket so I’m thinking it may just run from the machine batteries (24v)

thoughts please

Any idea what it draws mog?

 

[Mogman]

Any idea what it draws mog?

Not even looked at it properly just got dropped on my trailer it’s of one of these

Hartl Crusher - Crusher

Hartl Crusher – Hochwertige Excavator Buckets für Concrete Recycling. Spezialist für Bucket Crushers und Screeners im Bereich Stone Crushing.

www.hartl-crusher.com

 

[Mogman]

Any idea what it draws mog?

enlighten me as I don’t know the voltage, should I stick it on my dc welder, a couple of truck batteries or go the whole hog and give it 220v DC off my duck (which is out on site sadly)
don’t do much with electric hertz () too much

 

[bobthebuilder]

enlighten me as I don’t know the voltage, should I stick it on my dc welder, a couple of truck batteries or go the whole hog and give it 220v DC off my duck (which is out on site sadly)
don’t do much with electric hertz () too much

has it got any plugs /cables out of it ?

 

[Mogman]

has it got any plugs /cables out of it ?

I’ll take pictures tomorrow but has a 3 core cable poking out, quite heavy duty too

 

[doobin]

I’ll take pictures tomorrow but has a 3 core cable poking out, quite heavy duty too

If it was dc 24v it would need to be very heavy cable. Like inch diameter probably.

 

[V8Druid]

could Hartl tell you @Mogman ??

 

[muckyman]

It will be 24 volt

 

[Rob65]

Mog,

I have played with these things quite a lot, but it was a few years ago so I can’t remember all the details.

I suggest the first thing to do is have a poke around with a good test meter. If you check the resistance of the coil and also check for any electrical leakage to the case from both ends of the coil.

The way they fail is either damage to the insulation on the coils (caused by thermal movement or being bashed about on demolition sites) or getting water in them.

i rewound one once so even if it is knackered it may be recoverable.

I made a hydraulically powered generator unit so i could just hook it to the hammer lines on any hired machine rather than have a dedicated generator on the machine driven by a belt. The generator I used was 110v and had windings for welding.I dismantled the thing a few years ago but I still have the generator in the shed so will have a look and see if I can work it out. I think I used the welding windings but regulated it to give between 80 and 100v as I recall that’s what the big magnets used. If you look up Dynaset on the internet you will their (at the time too expensive for me) version of the same thing.

The control system is a bit more complicated than just switching the power on and off. If you just switch the power off the magnetic field takes time to decay and you will be sat waiting for the scrap to drop off. The solution to this is to use some large capacitors to store a charge and when the power to the magnet is cut off a relay switched and used the power in the capacitors to put a pulse or reverse polarity power on to the magnet coil to de-magnetise it.

Going back to you original question, the amount of power it will draw is dependant on the resistance. If for example it measures 2 Ohms and you were to run it on 100v that would draw 50 amps. 50 amps at 100v is 5kw which is about the minimum power you will require for handling heavy scrap. If you are just wanting to use it for ‘Hoovering up’ small stuff 2 or 3 kw may be sufficient.

Please let us know how you get on.

 

[Mogman]

Mog,

I have played with these things quite a lot, but it was a few years ago so I can’t remember all the details.

I suggest the first thing to do is have a poke around with a good test meter. If you check the resistance of the coil and also check for any electrical leakage to the case from both ends of the coil.

The way they fail is either damage to the insulation on the coils (caused by thermal movement or being bashed about on demolition sites) or getting water in them.

i rewound one once so even if it is knackered it may be recoverable.

I made a hydraulically powered generator unit so i could just hook it to the hammer lines on any hired machine rather than have a dedicated generator on the machine driven by a belt. The generator I used was 110v and had windings for welding.I dismantled the thing a few years ago but I still have the generator in the shed so will have a look and see if I can work it out. I think I used the welding windings but regulated it to give between 80 and 100v as I recall that’s what the big magnets used. If you look up Dynaset on the internet you will their (at the time too expensive for me) version of the same thing.

The control system is a bit more complicated than just switching the power on and off. If you just switch the power off the magnetic field takes time to decay and you will be sat waiting for the scrap to drop off. The solution to this is to use some large capacitors to store a charge and when the power to the magnet is cut off a relay switched and used the power in the capacitors to put a pulse or reverse polarity power on to the magnet coil to de-magnetise it.

Going back to you original question, the amount of power it will draw is dependant on the resistance. If for example it measures 2 Ohms and you were to run it on 100v that would draw 50 amps. 50 amps at 100v is 5kw which is about the minimum power you will require for handling heavy scrap. If you are just wanting to use it for ‘Hoovering up’ small stuff 2 or 3 kw may be sufficient.

Please let us know how you get on.

Cheers for that the magnet has never been fitted so brand new
as for the generator I converted a proper belt drive one to hydraulic (220 VDC) and got all the control box with it that is on the duck works ok but can’t travel with the generator running as the travel motor robs too much oil and it looses power to the genny which then drops the scrap off (need to find a better place to get hydraulic power from to stop this)
it’s only going to be for light stuff Probably

 

[Lancs Lad]

enlighten me as I don’t know the voltage, should I stick it on my dc welder, a couple of truck batteries or go the whole hog and give it 220v DC off my duck (which is out on site sadly)
don’t do much with electric hertz () too much

Robs the man

 

[Rob65]

Mog,
The system I made had the generator and control unit right on the back of the magnet.
That way you just shackle it on to the machine, plug the hoses in and you are good to go. Press the hammer button, magnet comes on, finger off the button magnet off. Simples.

It was about as simple as I could make it so that it could easily be moved between machines and even hung on a hired machine with no mods other that maybe adjusting the oil flow. Even that became unnecessary as after having blown a few seals on the hydraulic motor I put a flow restrictor and pressure relief valve on it that solved the problem.

Running at 220v sounds a bit high to me as you run the risk of over heating the magnet. Any idea how many amps it’s drawing? It’s probably ok if you are sitting in one place picking up, slewing and dropping scrap fairly quickly as the power is not on for long. If you want to pick up scrap and then carry it with the power on for a few mins you could well end up cooking the magnet.

If memory serves (which is not always the case these days ) the smaller 24 inch magnets were 5kw and the bigger 32 inch ones were about 8kw and they used to make quite a lot of steam when used in the rain.

 

[Mogman]

This is only a small magnet

the yellow wire is connected to the body
and the blue and brown have 1 ohm across them



this is the plate of it so I’m thinking 40cm x 50cm and 24v

if you look above the fuel tank you can see the generator that I got of a scrap handler with all the switch gear and magnet (40” I think)

 

[JD450A]

Hartl Crusher Shop | Iron Separator HBC 950 - Magnet Options

Hartl Crusher Shop | Iron Separator HBC 950 - Magnet Options im Hartl Crusher Shop.

www.hartl-crusher.com

24VDC

 

[Mogman]

Hartl Crusher Shop | Iron Separator HBC 950 - Magnet Options

Hartl Crusher Shop | Iron Separator HBC 950 - Magnet Options im Hartl Crusher Shop.

www.hartl-crusher.com

24VDC

now I looked last night and couldn’t find that

now to stick it on a set of batteries to see what it does Then sell the other one I have

 

[JD450A]

now I looked last night and couldn’t find that

now to stick it on a set of batteries to see what it does Then sell the other one I have

Those batteries ought to be trickl........ nah.

Let me know what you want for the other one Could use a magnet in a day or two to sweep the field.

 

[Mogman]

Those batteries ought to be trickl........ nah.

Let me know what you want for the other one Could use a magnet in a day or two to sweep the field.

Easy tiger

 

[Rob65]

This is only a small magnet
View attachment 34488
the yellow wire is connected to the body
and the blue and brown have 1 ohm across them
View attachment 34489

View attachment 34491
this is the plate of it so I’m thinking 40cm x 50cm and 24v
View attachment 34490
if you look above the fuel tank you can see the generator that I got of a scrap handler with all the switch gear and magnet (40” I think)

At 1 ohm on 24v that’s going to pull 24 amps so just shy of 600 watts. Do you know what the duty cycle on them is? If they are rated as 100% for continuous use you could probably get a bit more holding power from them by running on a slightly higher voltage for intermittent use.

They are so small, if you have a pair you could mount them side by side

 

[Gez_lewis]

ive never seen a 24v one, what will something like that hold?
I’ve always just used presumed they need a geny on the machine so stuck with a grab