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Hi there,
I have been studying relays and latching circuits myself these past few days. What I seem to have discovered so far is this. With a relay there are two separate parts there is the part that incorporates the electromagnet, and then there is the load part. The rating of a relay will be something like - 12 V, 30 A. So what you have here is that the electromagnet side requires a 12 V source or there abouts to energise the electromagnet, the electromagnet itself will draw power usually milliamps. The 30 A refers to the amount of current the load can handle that is the contacts that the magnet closes once it is energised. In other words, the two parts are electrically separate, you could hook up the load part to a 30 A load like a motor or heater or something that draws heavy power and you could activate that with a simple battery, even a 9 V battery would energise a relay like that.
I have a relay here that is rated 12 V, 8 A and i have tested all round it, it works with a 9 V battery (you might be able to go as low as 5 V but you can not go higher than a 12 V power supply without compromising the integrity of the relay), and the electromagnet draws 30 milliamps while energised.
So if I have my facts right, you can use very thin wire to activate the relay, but you will need something much thicker, I think 10 gauge wire is recommended for 30 amps, that is quite thick, about 5 mm in diameter. any less than that then you are in danger of heating up the wire used and it can cause a fire with that kind of current.
I hope this is helpful for you.
I have been studying relays and latching circuits myself these past few days. What I seem to have discovered so far is this. With a relay there are two separate parts there is the part that incorporates the electromagnet, and then there is the load part. The rating of a relay will be something like - 12 V, 30 A. So what you have here is that the electromagnet side requires a 12 V source or there abouts to energise the electromagnet, the electromagnet itself will draw power usually milliamps. The 30 A refers to the amount of current the load can handle that is the contacts that the magnet closes once it is energised. In other words, the two parts are electrically separate, you could hook up the load part to a 30 A load like a motor or heater or something that draws heavy power and you could activate that with a simple battery, even a 9 V battery would energise a relay like that.
I have a relay here that is rated 12 V, 8 A and i have tested all round it, it works with a 9 V battery (you might be able to go as low as 5 V but you can not go higher than a 12 V power supply without compromising the integrity of the relay), and the electromagnet draws 30 milliamps while energised.
So if I have my facts right, you can use very thin wire to activate the relay, but you will need something much thicker, I think 10 gauge wire is recommended for 30 amps, that is quite thick, about 5 mm in diameter. any less than that then you are in danger of heating up the wire used and it can cause a fire with that kind of current.
I hope this is helpful for you.
YES, possibly, but it may also be the maximum voltage ratings for the relay contacts
NO
The 30 amps is the rating of the relay contacts. The maximum they can switch before sustaining damage
The current drawn by the load is what determines what relay contach ratings you require. I would always use a relay
with ratings somewhat higher than what the load is drawing.
It is likely that the relay will have 2 sets of ratings for its contacts
DC and AC ratings and they will be quite different
Dave
Last edited:
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