Inductors or solenoids???

[ChrisGreece52]

If it says "high voltage", anything like "Nixie", "flyback", or "arc", or has any numbers with more than two digits ending in a "V", please, for the love of God back away from the circuit.

i did not get that sr.....but why ?

[c4757p]

Oh dear Mary mother of.... add "mains" to the above list.

[c4757p]

Because you will toast your ass.

[ChrisGreece52]

LOL thanks i will but the first one seems ok right ?

[c4757p]

The first one seems OK, but it's still a boost converter, so you may be able to give yourself a bit of a small zap off it if those LEDs aren't there to clamp the output voltage. You still won't die. It should be reasonably save unless you go mucking about with the voltages and component values. Note that I've successfully used almost the same exact circuit, with just a few modifications, to convert 12V into 300V at enough current to cook you. Inductors always have the potential (heh.) to be unsafe because they can "generate" voltage.

[ChrisGreece52]

The first one seems OK, but it's still a boost converter, so you may be able to give yourself a bit of a small zap off it if those LEDs aren't there to clamp the output voltage. You still won't die. It should be reasonably save unless you go mucking about with the voltages and component values. Note that I've successfully used almost the same exact circuit, with just a few modifications, to convert 12V into 300V at enough current to cook you. Inductors always have the potential (heh.) to be unsafe because they can "generate" voltage.

OK ill keep searching

[JackOfVA]

In the radio side of engineering, a solenoidal inductor means one that is wound around an open, straight core, which may be air (if the wire is large enough diameter to support it) or plastic or ceramic or similar material, or a magnetic rod core. Its purpose is to act like an inductor, e.g, in a tuned circuit or to provide inductive reactance where DC may need to pass but AC signals need stopped (RF choke is one example.)

In industrial electrical work, or automotive use amongst others, a solenoid means a mechanism whereby a electromagnet pulls (or, less commonly, pushes) an armature. Its purpose is to convert electrical energy to a mechanical action.

Also in automotive use, a high current rated relay used to connect the starter motor to the battery is often called a solenoid instead of a relay.

These terms are widely used in American engineering use, but I don't know if the UK or Australia have different words.

[c4757p]

Also in automotive use, a high current rated relay used to connect the starter motor to the battery is often called a solenoid instead of a relay.

Automotive didn't even occur to me. They seem to have invented a completely different set of terms for just about everything...

[IanB]

A solenoid means an electromagnet designed to pull some kind of iron bolt or plunger. I didn't even know there was another meaning out there...

[c4757p]

The relay that switches the starter motor in a car is indeed routinely called the "start(er) solenoid". I suppose they need some name for it - I know at least in my car, the coil current of this beast is so high that it is itself switched by a smaller relay! Which one is the "starter relay"?

I guess the coil in a relay technically is a solenoid, but I kind of thought we agreed to call it a 'relay' when the thing it moves is an electric switch! 

And the all-knowing Wikipedia confirms that it does not have to move anything at all to be a solenoid.

This was new to me too, actually. I double-checked before attempting an answer. Didn't remember about the automotive one though.

[IanB]

I quickly checked Wikipedia, but it affirms the main principle. The primary purpose of a solenoid is to generate magnetism, not to have inductance. In essence, a solenoid is a physical device, not an electronic device. This is true even if the magnetic field is not immediately used for any specific purpose.

[c4757p]

The primary purpose of a solenoid is to generate magnetism, not to have inductance.

Tomato, tomato.

Er... that doesn't work so well in print.


But yes, I agree 

[NiHaoMike]

The relay that switches the starter motor in a car is indeed routinely called the "start(er) solenoid". I suppose they need some name for it - I know at least in my car, the coil current of this beast is so high that it is itself switched by a smaller relay! Which one is the "starter relay"?

I guess the coil in a relay technically is a solenoid, but I kind of thought we agreed to call it a 'relay' when the thing it moves is an electric switch! 

And the all-knowing Wikipedia confirms that it does not have to move anything at all to be a solenoid.

This was new to me too, actually. I double-checked before attempting an answer. Didn't remember about the automotive one though.

I thought the solenoid was the part that mechanically engaged the starter.

[c4757p]

You have a point - it often does both, though it varies from car to car. Mine is purely electrical with a separate, "automatic" mechanism to engage and disengage.

[SeanB]

So you have a Bendix starter, not too common nowdays except on smaller motorcycles. The most common now is the preengaged starter with overrun mechanism. There the solenoid engages the starter gear onto the flywheel before the starter is powered by a set of large contacts that only close when the gear is fully engaged. As the engine starts to spin up the gear can move faster than the motor can drive it because it has an overrun clutch that allows it to run faster than the shaft but not the other way.

The Bendix uses a spiral cut keyway on the motor shaft. As the motor starts the inertia of the large mass gear cause it to move out and engage the flywheel. When the flywheel speeds up as the engine fires it pushes the gear back down out of engagement.

[ChrisGreece52]

In the radio side of engineering, a solenoidal inductor means one that is wound around an open, straight core, which may be air (if the wire is large enough diameter to support it) or plastic or ceramic or similar material, or a magnetic rod core. Its purpose is to act like an inductor, e.g, in a tuned circuit or to provide inductive reactance where DC may need to pass but AC signals need stopped (RF choke is one example.)

In industrial electrical work, or automotive use amongst others, a solenoid means a mechanism whereby a electromagnet pulls (or, less commonly, pushes) an armature. Its purpose is to convert electrical energy to a mechanical action.

Also in automotive use, a high current rated relay used to connect the starter motor to the battery is often called a solenoid instead of a relay.

These terms are widely used in American engineering use, but I don't know if the UK or Australia have different words.

Thanks for the information!!!

[ChrisGreece52]

I quickly checked Wikipedia, but it affirms the main principle. The primary purpose of a solenoid is to generate magnetism, not to have inductance. In essence, a solenoid is a physical device, not an electronic device. This is true even if the magnetic field is not immediately used for any specific purpose.

so an electromagnet could be also called a solenoid

[AlfBaz]

so an electromagnet could be also called a solenoid

You can call it what you like
So far we have inductor, relay, solenoid and now electromagnet

A generalisation for each of them could be something like this

They're all inductors, hell even a piece of wire has inductance but generally speaking when referring to an inductor, you are referring to a device that provides an inductance value and that inductance is affecting the electrical signal, by design or by frustration

A relay has a fixed core within a coil that when energised will attract an armature that does something, such as switch contacts and if the contacts are big enough you can call it a contactor.

A solenoid will have a moving core. When the coil is energised the magnetism pulls a plunger into the coil, the plunger is usually attached to some mechanical actuator. In the case of a starter motor, it moves the starter motor's cog into the flywheel gear and makes a large contact to provide current for the starter motor. Starter motors are normally series motors who's terminating speed is when the armature throws the windings out in a big sparkly mess... So its good to have it not start until the cog is fully engaged

An electromagnet will generally have a fixed core and nothing else. When the coil is energised the core becomes magnetised and that's it. These tend to be DC only. Metal scrap yards tend to use them to pick up metallic waste. In steel making plants several of them are placed in a row to pick up large metal slabs. I'm sure the magnetic field generated by electromagnets have many more uses but in some instances they may be called something different again, such as field or winding...

[mikes]

I'm surprised no one has mentioned that the "strange shaped" inductor is simply wound on a toroidal core. This is commonly done to prevent field leakage, the flux stays within the core.

There's no way to easily calculate the inductance. It will depend on the permeability of the core. Toroid manufacturer's often color code the cores, but there's no standard for that. Coming off a PC motherboard, they could have been painted a certain color just to add bling.

[ChrisGreece52]

so an electromagnet could be also called a solenoid

You can call it what you like
So far we have inductor, relay, solenoid and now electromagnet

A generalisation for each of them could be something like this

They're all inductors, hell even a piece of wire has inductance but generally speaking when referring to an inductor, you are referring to a device that provides an inductance value and that inductance is affecting the electrical signal, by design or by frustration

A relay has a fixed core within a coil that when energised will attract an armature that does something, such as switch contacts and if the contacts are big enough you can call it a contactor.

A solenoid will have a moving core. When the coil is energised the magnetism pulls a plunger into the coil, the plunger is usually attached to some mechanical actuator. In the case of a starter motor, it moves the starter motor's cog into the flywheel gear and makes a large contact to provide current for the starter motor. Starter motors are normally series motors who's terminating speed is when the armature throws the windings out in a big sparkly mess... So its good to have it not start until the cog is fully engaged

An electromagnet will generally have a fixed core and nothing else. When the coil is energised the core becomes magnetised and that's it. These tend to be DC only. Metal scrap yards tend to use them to pick up metallic waste. In steel making plants several of them are placed in a row to pick up large metal slabs. I'm sure the magnetic field generated by electromagnets have many more uses but in some instances they may be called something different again, such as field or winding...

THANK YOU!!!

[JackOfVA]

I'm surprised no one has mentioned that the "strange shaped" inductor is simply wound on a toroidal core. This is commonly done to prevent field leakage, the flux stays within the core.

There's no way to easily calculate the inductance. It will depend on the permeability of the core. Toroid manufacturer's often color code the cores, but there's no standard for that. Coming off a PC motherboard, they could have been painted a certain color just to add bling.

And if it's a ferrite core, the ferrite mix may have been selected to provide high loss (low Q) if its purpose is to suppress unwanted high frequency noise, or EMI suppression as it's known. Using a high loss ferrite core for other purposes will lead to "interesting" results.

My guess is that the toroid cores are EMI control devices, but it's certainly possible they are filtering inductors in the switching supply. These two uses have rather different core material requirements.