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Air compressor auto off

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niget2002

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I know this has been discussed, but I want to double check my thinking.

What I'm thinking about doing is running a cable off of a 120v smart outlet to a 120v triggered contactor. Turning the outlet on via Alexa or push-button should activate the contactor.

The contactor I found is for 3 phase, but I should be able to just use two of the poles for switching my load.

Any thing I'm missing with this?

The contactor I'm looking at is this one. My motor is smaller than what's listed in the description.

 
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wyliesdiesels

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Modesto, CA
niget2002 said:
I know this has been discussed, but I want to double check my thinking.

What I'm thinking about doing is running a cable off of a 120v smart outlet to a 120v triggered contactor. Turning the outlet on via Alexa or push-button should activate the contactor.

The contactor I found is for 3 phase, but I should be able to just use two of the poles for switching my load.

Any thing I'm missing with this?

The contactor I'm looking at is this one. My motor is smaller than what's listed in the description.

Click to expand...
what is the HP rating on the motor as shown on the nameplate?
 
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niget2002

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mm08822

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niget2002 said:
I know this has been discussed, but I want to double check my thinking.

What I'm thinking about doing is running a cable off of a 120v smart outlet to a 120v triggered contactor. Turning the outlet on via Alexa or push-button should activate the contactor.

The contactor I found is for 3 phase, but I should be able to just use two of the poles for switching my load.

Any thing I'm missing with this?

The contactor I'm looking at is this one. My motor is smaller than what's listed in the description.

Click to expand...
Using 2 of the 3 poles will be fine.
A 5hp rating should provide longer contact life when using a 3 hp load. Also these contacts will rarely see make/break full load currents. Elsewhere in the circuit will (as it already does today).

You may want to add a local switch to whatever enclosure you are putting this in so it can't be controlled from other sources while performing local servicing. Keep in mind there will be 2 electrical sources on this contactor.

What enclosure will this be housed in?
Use the lugs for connection. Do not use the sta-kon connections for the power circuit.
Is the compressor hard-wired or on a plug/recept?
Motor already has overload protection?
 
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wyliesdiesels

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niget2002 said:
I found this one that's a 2 pole 120vac trigger. It says it's UL certified.

Amazon.com: Appli Parts APAC-1S4024 Heavy Duty 1 Pole with Shunt Contactor 40 Amp 24 Volt Coil Replacement for ac Compressor and Electrical Applications UL 476929 : Industrial & Scientific

Amazon.com: Appli Parts APAC-1S4024 Heavy Duty 1 Pole with Shunt Contactor 40 Amp 24 Volt Coil Replacement for ac Compressor and Electrical Applications UL 476929 : Industrial & Scientific
a.co
Click to expand...
not HP rated and UL doesnt certify, they LIST.

I wouldnt buy no name parts like that
 
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mm08822

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wyliesdiesels said:
not HP rated and UL doesnt certify, they LIST.

I wouldnt buy no name parts like that
Click to expand...
I did see some labeled contactors not specifying rated hp or for a specific voltage use. Then I looked at the mfr's spec sheet and the info was there. A labeling real estate issue I suppose.

However, the descriptions appearing on Amazon are clearly by those not in the know or simply marketing-snakes. Buyer beware!
 
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niget2002

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mm08822 said:
What enclosure will this be housed in?
Use the lugs for connection. Do not use the sta-kon connections for the power circuit.
Is the compressor hard-wired or on a plug/recept?
Motor already has overload protection?
Click to expand...
I unplug electrical devices when working on them.

I have a plastic electric box to house it in. Plan is to mount the box on the wall behind the compressor with a receptacle to plug the compressor into. I haven't decided if the receptacle is hard mounted to the box with a faceplate or a plug on the end of a whip. Idea is that if the 'automation' or contactor ever dies and I need the compressor, I can unplug it from the contact box and plug it back into the wall. I have grommets and strain relief for the power whip into the box and the electrical whip to plug into the 120vac outlet/switch. Although with the box mounted to the wall, it shouldn't vibrate when the compressor is running. I even thought about going crazy and mounting a light fixture on the outside of the box to light up a LED bulb when the 120vac trigger is hot.

I plan on using the lugs. I'm not a fan of the spade connectors. Those things never seem to stay put.

Compressor is plugged in, but I used a twist-lock receptacle. Although the compressor is on pads, so shouldn't walk away from the wall. Or, at least it hasn't in the last 3 years I've had it.

Motor does have overload already on it.
Bad Habit said:
Click to expand...
Thanks for the link. I'll go with that one. Double the cost means double the pleasure I assume?

wyliesdiesels said:
not HP rated and UL doesnt certify, they LIST.

I wouldnt buy no name parts like that
Click to expand...
point made.
 
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