Amp draw of coil based relays
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Amp draw of coil based relays

 
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Ignoramus21666
Guest
Posted: Tue Dec 06, 2005 11:59 pm    Post subject: Amp draw of coil based relays Reply with quote
Does anyone have any idea as to how many milliamps do small coil based
relays (12v coil) draw, typically?

i

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Tim Shoppa
Guest
Posted: Wed Dec 07, 2005 12:07 am    Post subject: Re: Amp draw of coil based relays Reply with quote
Quote:
Does anyone have any idea as to how many milliamps
do small coil based relays (12v coil) draw, typically?

Automotive relays are typically 150-200mA ("72 ohm coil").

Smallish reed relays with 12V coils are in the 12mA range. ("1K ohm
coil").

As I hint above, relay specs are typically given in coil resistance.

Tim.
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Spehro Pefhany
Guest
Posted: Wed Dec 07, 2005 12:12 am    Post subject: Re: Amp draw of coil based relays Reply with quote
On Tue, 06 Dec 2005 17:59:03 GMT, the renowned Ignoramus21666
<ignoramus21666@NOSPAM.21666.invalid> wrote:

Quote:
Does anyone have any idea as to how many milliamps do small coil based
relays (12v coil) draw, typically?

i

Depends on what you mean by small, but small power relays (eg. a few
A) typically consume in the hundreds of mW (eg. 360mW). At 12V, that's
30mA. You can probaby find some in the 100mA range. Generally, coil
power goes up with switching current, lifetime and voltage isolation,
so relays made to more stringent European safety standards tend to use
a bit more power.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

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Dan Hollands
Guest
Posted: Wed Dec 07, 2005 12:14 am    Post subject: Re: Amp draw of coil based relays Reply with quote
If you know the make an model you can look it up

Or

You can measure the coil resistance with an ohm meter and calculate it

Dan

--
Dan Hollands
1120 S Creek Dr
Webster NY 14580
585-872-2606
dhollan3@rochester.rr.com
www.QuickScoreRace.com
"Ignoramus21666" <ignoramus21666@NOSPAM.21666.invalid> wrote in message
news:Hjklf.19807$bg5.13221@fe84.usenetserver.com...
Quote:
Does anyone have any idea as to how many milliamps do small coil based
relays (12v coil) draw, typically?

i
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Ignoramus21666
Guest
Posted: Wed Dec 07, 2005 12:28 am    Post subject: Re: Amp draw of coil based relays Reply with quote
Thanks, Spehro, Tim, and Dan.

I am trying to buy some cheap relays to let my kid play with his toy
LifeLike railroad.

He is very much into traffic lights and this railroad.

For example, if a train approaches a RR traffic light, and it is red
or yellow, stop the train. If a train approaches a crossing, light red
light on the crossing. Etc. It should be very easy with a 12v power
supply and some relays and alligator clips, and maybe light switches
or some such.

We already have a power supply, traffic light etc.

So, I am looking to buy some cheap 12v coil relays. Hence my question.

i

On Tue, 06 Dec 2005 18:14:51 GMT, Dan Hollands <dhollan3@rochester.rr.com> wrote:
Quote:
If you know the make an model you can look it up

Or

You can measure the coil resistance with an ohm meter and calculate it

Dan



--
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John Fields
Guest
Posted: Wed Dec 07, 2005 1:31 am    Post subject: Re: Amp draw of coil based relays Reply with quote
On Tue, 06 Dec 2005 18:28:54 GMT, Ignoramus21666
<ignoramus21666@NOSPAM.21666.invalid> wrote:

Quote:
Thanks, Spehro, Tim, and Dan.

I am trying to buy some cheap relays to let my kid play with his toy
LifeLike railroad.

He is very much into traffic lights and this railroad.

For example, if a train approaches a RR traffic light, and it is red
or yellow, stop the train. If a train approaches a crossing, light red
light on the crossing. Etc. It should be very easy with a 12v power
supply and some relays and alligator clips, and maybe light switches
or some such.

We already have a power supply, traffic light etc.

So, I am looking to buy some cheap 12v coil relays. Hence my question.

---
Potter and Brumfield T7NS5D1-12

http://relays.tycoelectronics.com/datasheets/T7N_DS.pdf

Digi-Key and Mouser both stock them at $1.32

--
John Fields
Professional Circuit Designer
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Ignoramus21666
Guest
Posted: Wed Dec 07, 2005 1:35 am    Post subject: Re: Amp draw of coil based relays Reply with quote
On Tue, 06 Dec 2005 13:31:57 -0600, John Fields <jfields@austininstruments.com> wrote:
Quote:
On Tue, 06 Dec 2005 18:28:54 GMT, Ignoramus21666
ignoramus21666@NOSPAM.21666.invalid> wrote:

Thanks, Spehro, Tim, and Dan.

I am trying to buy some cheap relays to let my kid play with his toy
LifeLike railroad.

He is very much into traffic lights and this railroad.

For example, if a train approaches a RR traffic light, and it is red
or yellow, stop the train. If a train approaches a crossing, light red
light on the crossing. Etc. It should be very easy with a 12v power
supply and some relays and alligator clips, and maybe light switches
or some such.

We already have a power supply, traffic light etc.

So, I am looking to buy some cheap 12v coil relays. Hence my question.

Potter and Brumfield T7NS5D1-12

http://relays.tycoelectronics.com/datasheets/T7N_DS.pdf

Digi-Key and Mouser both stock them at $1.32

Thanks. I bought some 50 Sigma 12v 4 pole SPDT relays at 60 cents apiece
on ebay... I hope that they should work fine. The power supply has
quite a bit of extra power available after powering the toy train, so
amp draw of coils should not be a huge issue.

i
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Ignoramus21666
Guest
Posted: Wed Dec 07, 2005 1:35 am    Post subject: Re: Amp draw of coil based relays Reply with quote
On Tue, 06 Dec 2005 13:31:57 -0600, John Fields <jfields@austininstruments.com> wrote:
Quote:
On Tue, 06 Dec 2005 18:28:54 GMT, Ignoramus21666
ignoramus21666@NOSPAM.21666.invalid> wrote:

Thanks, Spehro, Tim, and Dan.

I am trying to buy some cheap relays to let my kid play with his toy
LifeLike railroad.

He is very much into traffic lights and this railroad.

For example, if a train approaches a RR traffic light, and it is red
or yellow, stop the train. If a train approaches a crossing, light red
light on the crossing. Etc. It should be very easy with a 12v power
supply and some relays and alligator clips, and maybe light switches
or some such.

We already have a power supply, traffic light etc.

So, I am looking to buy some cheap 12v coil relays. Hence my question.

Potter and Brumfield T7NS5D1-12

http://relays.tycoelectronics.com/datasheets/T7N_DS.pdf

Digi-Key and Mouser both stock them at $1.32


Thanks, that's good stuff. I will try to find something like that for
less on ebay, if not, I will buy some new ones.

i
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Robert Latest
Guest
Posted: Mon Dec 12, 2005 5:35 pm    Post subject: Re: Amp draw of coil based relays Reply with quote
On Tue, 06 Dec 2005 17:59:03 GMT,
Ignoramus21666 <ignoramus21666@NOSPAM.21666.invalid> wrote
in Msg. <Hjklf.19807$bg5.13221@fe84.usenetserver.com>
Quote:
Does anyone have any idea as to how many milliamps do small coil based
relays (12v coil) draw, typically?

Datasheets and ammeters usually have pretty good ideas about how much
current things draw.

robert
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