relay or solenoid

I have a manual battery isolator for the Aux Battery in the rear of the vehicle, plus a tmax system fitted , however i want to be able to engage the aux from the cab via a rocker switch, Should I be using a relay or a solenoid, (i just happen to have solenoid from an old tmax system knocking about)

Generally the terms get mixed and physically they are very similar ie they use an electro magnet to move something. It's normally taken that a relay is used to open and close a circuit remotely and a solenoid is used to cause linear movement. So solenoid to lock the doors relay for battery cut off.
Are you sure what you have is a solenoid and not a relay?

Jam1 said:

Generally the terms get mixed and physically they are very similar ie they use an electro magnet to move something. It's normally taken that a relay is used to open and close a circuit remotely and a solenoid is used to cause linear movement. So solenoid to lock the doors relay for battery cut off.
Are you sure what you have is a solenoid and not a relay?

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yup. it's a solenoid, from a T-max dual battery system,

Jam1 said:

Generally the terms get mixed and physically they are very similar ie they use an electro magnet to move something. It's normally taken that a relay is used to open and close a circuit remotely and a solenoid is used to cause linear movement. So solenoid to lock the doors relay for battery cut off.
Are you sure what you have is a solenoid and not a relay?

Click to expand...

The confusion arises when a solenoid actually "does" both functions - like on a pre-engaged starter. Although the solenoid doesn't actually directly connect the power, like a relay would in this case.....

nigel cartwright said:

yup. it's a solenoid, from a T-max dual battery system,

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I suspect, and am happy to be corrected, that its just a large heavy duty relay....

we have some here, on dual battery systems that are physically quite large....

nigel cartwright said:

yup. it's a solenoid, from a T-max dual battery system,

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It look like this?

Jam1 said:

It look like this?

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exactly the same

Disco1BFG said:

I suspect, and am happy to be corrected, that its just a large heavy duty relay....

we have some here, on dual battery systems that are physically quite large....

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thats pretty much what im aiming for, want to put it across the postive or negative (dont think it matters) terminal of the aux

nigel cartwright said:

That sounds prety much what im aiming for

exactly the same

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Tis a relay then - a large and "don't drop it on your toe relay", but a relay non the less...

( there is one on a digger here that is the size of a pint pot, 24V, and if you connect it to power on the bench, the damn thing jumps into the air - made me jump the first time i tested it!)

Disco1BFG said:

Tis a relay then - a large and "don't drop it on your toe relay", but a relay non the less...

( there is one on a digger here that is the size of a pint pot, 24V, and if you connect it to power on the bench, the damn thing jumps into the air - made me jump the first time i tested it!)

Click to expand...

not that big ,around 2.5 inches , 1.5 diameter,, makes a reassuringly solid 'clonk' when it's connected,

Yep, It's a big relay. But it could be called a solenoid, in the electrical switching service, at a certain contact size (nobody knows what size) a relay becomes a solenoid. Depending on who's designing or using the circuit it could be a contactor, that's what people in the electricity supply game tend to call them. If you go very small in the electronics business they are called reeds. People who use them every day tend to know instinctively what to call them, but basically they all do the same job, use a small electric current to switch a larger electric current.

Use the solenoid you would need a serious relay to carry full load battery amps.

brian47 said:

..snip.... But it could be called a solenoid, in the electrical switching service, at a certain contact size (nobody knows what size) a relay becomes a solenoid.

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It could be called a solenoid, but that, IMHO would not be technically correct - a quote from wikipedia :- https://en.wikipedia.org/wiki/Solenoid
explains this pretty well....

"In engineering, the term may also refer to a variety of transducer devices that convert energy into linear motion. The term is also often used to refer to a solenoid valve, which is an integrated device containing an electromechanical solenoid which actuates either a pneumatic or hydraulic valve, or a solenoid switch, which is a specific type of relay that internally uses an electromechanical solenoid to operate an electrical switch; for example, an automobile starter solenoid, or a linear solenoid, which is an electromechanical solenoid. Solenoid bolts, a type of electronic-mechanical locking mechanism, also exist."

brian47 said:

.....snip..... it could be a contactor,

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I blinkin knew there was another name that is used, but could I remember it . Thanks for reminding me[/QUOTE]

Disco1BFG said:

It could be called a solenoid, but that, IMHO would not be technically correct - a quote from wikipedia :- https://en.wikipedia.org/wiki/Solenoid
explains this pretty well....

"In engineering, the term may also refer to a variety of transducer devices that convert energy into linear motion. The term is also often used to refer to a solenoid valve, which is an integrated device containing an electromechanical solenoid which actuates either a pneumatic or hydraulic valve, or a solenoid switch, which is a specific type of relay that internally uses an electromechanical solenoid to operate an electrical switch; for example, an automobile starter solenoid, or a linear solenoid, which is an electromechanical solenoid. Solenoid bolts, a type of electronic-mechanical locking mechanism, also exist."



I blinkin knew there was another name that is used, but could I remember it . Thanks for reminding me

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[/QUOTE]

Think solenoid activated high load switch.

wammers said:

Think solenoid activated high load switch.

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its a blinkin relay, or a contactor, it's not a solenoid

Disco1BFG said:

its a blinkin relay, or a contactor, it's not a solenoid

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Nope it looks like a solenoid activated high load switch to me. Just like a starter solenoid. Which is also a solenoid activated high load switch. There are contacts in it that's for sure. But you can call it a contactor if you really want to.

Just to be a Pedant - in the automotive industry - must relays contain a solenoid .!

what ever it is.. it worked...!