High Power Relay

Can anyone recommend a packaged solution for a higher-ish powered AC relay to run off Arduino, 20+ amps? (note, I can probably build one but was looking for a mount-able packaged solution)

I found a few 10A ones on ebay but would prefer to hear from folks who have driven higher loads (2hp pump for example).

Or, if folks are using smaller relays to drive ac coiled commercial style relays, that would be good to hear too, or TRIACs, or whatever.

Thanks in advance.

kev_rm: Can anyone recommend a packaged solution for a higher-ish powered AC relay to run off Arduino, 20+ amps? (note, I can probably build one but was looking for a mount-able packaged solution)

I found a few 10A ones on ebay but would prefer to hear from folks who have driven higher loads (2hp pump for example).

Or, if folks are using smaller relays to drive ac coiled commercial style relays, that would be good to hear too, or TRIACs, or whatever.

Thanks in advance.

20 amps OK, but at what maximum voltage? Single phase or 3 phase? What relay coil voltage do you wish to have?

Lefty

Sorry, to clarify, 120V 60hz, 20A Single Phase. Suitable for inductive loads as well.

Relays made for air compressors, heat pumps, and such, might work

Found the below, assuming 10ma is doable @ 5V :) A little pricey $33

http://www.teledynerelays.com/pdf/industrial/sh.pdf

lots of relays made for the arduino.

http://www.ebay.com/sch/i.html?_trksid=p5197.m570.l1311&_nkw=arduino%20relay&_sacat=0&_from=R40&_clu=2&_fcid=1&_localstpos&_stpos&gbr=1

kev_rm:
Found the below, assuming 10ma is doable @ 5V :slight_smile: A little pricey $33

http://www.teledynerelays.com/pdf/industrial/sh.pdf

Yea, but not a slam dunk working into inductive loads like motors. And SSRs working at these currents require a large heatsink.

Lefty

controlling a 20amp AC motor @120VAC is a serious load and you need a relay rated well above the motor amps. Here is the type of relay you should be looking for:

http://www.ebay.com/itm/3EA-DELTROL-12VDC-CONTACTOR-RELAY-NORMALLY-OPEN-30-AMP-/190774211566?pt=LH_DefaultDomain_0&hash=item2c6b0773ee

or

http://www.ebay.com/itm/425BXX-12VDC-STRUTHERS-DUNN-30-A-AMP-12VDC-COIL-/290805751256?pt=LH_DefaultDomain_0&hash=item43b55f9dd8

Lefty

Was looking for a recommendation? Anyone have direct experience with a high power application?

zoomkat: lots of relays made for the arduino.

http://www.ebay.com/sch/i.html?_trksid=p5197.m570.l1311&_nkw=arduino%20relay&_sacat=0&_from=R40&_clu=2&_fcid=1&_localstpos&_stpos&gbr=1

kev_rm: Was looking for a recommendation? Anyone have direct experience with a high power application?

zoomkat: lots of relays made for the arduino.

http://www.ebay.com/sch/i.html?_trksid=p5197.m570.l1311&_nkw=arduino%20relay&_sacat=0&_from=R40&_clu=2&_fcid=1&_localstpos&_stpos&gbr=1

Well the highest current rating I could find from that list is a 30 amp rated relay. ( http://arduino.cc/forum/index.php?action=post;quote=1045897;topic=139180.0;num_replies=8;sesc=ba0bf09b4674226035a12331ef203a12 )

But be aware that because a motor is a very inductive load, contact current and voltage rating alone is not enough to properly select a relay to safely control an AC motor of any significant power. Note the horsepower rating on that relay ( 1/2 HP ), so even though 1/2 horsepower is only 3.1 amps at 120vac (1HP = 750 watts) it takes a 30amp current rating to support that much motor power. So whatever relay you select be sure it's rated for both the maximum amps and voltage and if controlling a AC motor, also it's maximum horsepower rating.

Lefty

Lefty

Can anyone recommend a packaged solution for a higher-ish powered AC relay to run off Arduino, 20+ amps?

Not exactly common in the realm amateur hobbyist electronics: high-power AC mains voltage (+20amps) and neatly pre-packaged. Your pickins are gonna be pretty slim.10 amps-no problem, but I don’t think I have ever seen a manufactured product capable of that much current and driven by 5v arduino. In my experience, I have used heavy duty HVAC relays to switch 25-30 amp loads; but they don’t come cheap new (check ebay), and you will need a smaller relay to drive the coil. Another already-mentioned possibility is an SSR w/ heatsink.

If you like to experiment, you might try a car starter relay. The insulation on the contact wiring probably is good for 120v.

What about this? Says it's rated to 30A and has that friendly look to it.

http://www.dx.com/p/1-channel-5v-30a-high-power-relay-module-for-arduino-8051-avr-pic-dsp-arm-153000#.VbqusJNVhBc