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-   -   Contactor relay source (http://www.homebrewtalk.com/f170/contactor-relay-source-252031/)

njbabs 06-18-2011 05:36 PM

Contactor relay source
 
I'm trying to determine whether this is an appropriate relay for a build per theelectricbrewery.com to use as a disconnect with a switch after the SSR. Would this work?

http://www.newark.com/jsp/search/pro...sp?sku=12T3481

I know this isn't a coil contactor like @ http://www.theelectricbrewery.com/co...part-2?page=13
hence the question.

djsethall 06-18-2011 05:41 PM

Do you plan on doing multiple batches at one time? If you do, you will need to run your HLT and your boiler at the same time. But yes, that relay will work

njbabs 06-18-2011 07:59 PM

I'm planning a two vessel system for now with a combo HLT/Kettle. Not anticipating serial batches (yet?). Thanks.

John0872 06-28-2011 06:57 PM

This is the one a lot of people, including myself, use.

http://www.pioneerbreaker.com/Produc...CN-PBC302-120V

P-J 06-28-2011 07:53 PM

Quote:

Originally Posted by njbabs (Post 3015885)
I'm trying to determine whether this is an appropriate relay for a build per theelectricbrewery.com to use as a disconnect with a switch after the SSR. Would this work?

http://www.newark.com/jsp/search/pro...sp?sku=12T3481

I know this isn't a coil contactor like @ http://www.theelectricbrewery.com/co...part-2?page=13
hence the question.

I had not seen that contactor from newark.com before. IMHO it is an excellent unit for a few reasons. It's rated very well for our purposes. It's DIN rail mountable which gives nice options for laying out an all electric controller. It's a DPDT contactor which expands the possibilities for a variety of control methods. It is a lot smaller than the typical contactor. It is also enclosed making it much safer when you put your hands in the controller during setup and diagnosing during the build.

Thanks for posting the link. I know what I'll be using now on some of my controller diagrams.

P-J

Walker 07-14-2011 05:14 PM

That newark contactor is nice, but does anyone have better specs on it?

Looking at the table newark has for that family of contactors (here), it claims that the coil resistance is "1.6" for the 120v coil relays.

If that's 1.6 Ohms, then that would mean that the coil pulled 75 amps, which can't possibly be true.

sdugre 07-14-2011 08:24 PM

I think the inductance of the coil has a more significant affect on the current draw than resistance.

To illustrate, I have a 120V contactor coil with a resistance of 340 ohms that only draws 45 mA. If you were to calculate it with ohms law you'd get 353 mA.

Walker 07-14-2011 08:30 PM

good point.

P-J 07-14-2011 11:20 PM

Quote:

Originally Posted by Walker (Post 3086087)
That newark contactor is nice, but does anyone have better specs on it?

Looking at the table newark has for that family of contactors (here), it claims that the coil resistance is "1.6" for the 120v coil relays.

If that's 1.6 Ohms, then that would mean that the coil pulled 75 amps, which can't possibly be true.

The link posted for the contactor lists the resistance as
Quote:

Description
POWER RELAY, 120VAC, 30A, DPDT, DIN RAIL
Relay Type: Power
Coil Voltage VAC Nom: 120V
Contact Current Max: 30A
Contact Voltage AC Nom: 277V
Contact Voltage DC Nom: 28V
Coil Resistance: 1.6 kohm
Contact Configuration: DPDT
RoHS Compliant: Yes


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