Wiring compressor so I don't leave it on

[ericm]

The electrician is doing some of the wiring on the shop. I had the idea of running a 120v wire to the a switch by the man door (next to the light switches) which I would use to trigger a solenoid that switches power to the 5hp compressor. When I leave for the day I would flip that switch off along with the light switches.

The electrician suggested a countdown timer switch like the spring loaded ones that turn on the heat lamp in a motel room but I kinda don't like that as they tend to go off when I'm in the middle of something.

Any other ideas?

 

[u2slow]

If the compressor uses a starter/contactor, it's very easy to switch the control power at the light switch.

If it's just a line-start pressure switch on the machine, then you may as well train yourself to switch it locally, or kick off the breaker when you close up the shop.

 

[Citation]

If the compressor uses a starter/contactor, it's very easy to switch the control power at the light switch.

If it's just a line-start pressure switch on the machine, then you may as well train yourself to switch it locally, or kick off the breaker when you close up the shop.

I agree with this.

A number of threads have covered this topic. With a starter contactor it's relatively easy as you just need to wire a low current (but 240V) relay inline with the pressure switch. You flip the switch, the relay turns off then the pressure switch can't turn on the motor. You could even make it a simple switched outlet by the compressor then get a simple 12 control (240V double pole) relay and power it off a simple 12V wall wart. Plug a lamp into the other plug in the switched outlet. If the lamp is on, so is the compressor.


If your compressor doesn't use a starter then it may be worth it to add one. A 5ho motor rated relay is basically a starter.

 

[larry4406]

I plan to do similar but also install an electric ball valve that shuts off the air.

 

[ericm]

A lot of the more affordable 5hp compressors use pressure switches. I was planning on converting to a contactor.

My present setup has a 2hp compressor with the usual pressure switch, in a cabinet. For whatever reason, I sometimes forget to shut it off.

I'm also considering plumbing in an electric valve to close off the piping when the compressor is turned off.

 

[ArcReactorKC]

If we are going to "automated" solutions like your electrician is suggesting you could put an aqara presence sensor and a smart relay in that would only allow the compressor to run when it senses a living human in the shop.

 

[wyliesdiesels]

A lot of the more affordable 5hp compressors use pressure switches. I was planning on converting to a contactor.

My present setup has a 2hp compressor with the usual pressure switch, in a cabinet. For whatever reason, I sometimes forget to shut it off.

I'm also considering plumbing in an electric valve to close off the piping when the compressor is turned off.

if no contactor on the current setup, you would need a motor rated switch such as the leviton model below

Leviton 60 Amp 600 Volt Industrial Grade Double Pole Single Phase AC Manual Motor Controller Toggle Switch - Black MS602-BW MS602-BW - The Home Depot

Leviton's line of industrial grade AC Manual Motor Controllers provide safe, reliable control of a variety of motor loads. Typical applications include manual ON/OFF switching control of bottling lines,

www.homedepot.com

 

[mm08822]

Or just fix all of the leaks so the system holds pressure.

 

[ArcReactorKC]

Or just fix all of the leaks so the system holds pressure.

I would still suggest shutting off the compressor when it will be unattended for a while.
There are many cases of a leak causing compressor over run.

 

[kabinenroller]

I wired a 110volt light fixture with a red LED bulb to one leg of the 220v on the disconnect box for my compressor. When the power is turned on by flipping the disconnect box lever the compressor gets 220 and the fixture gets 110. My compressor is in a separate room of my shop and the fixture is in the main work area within clear sight from anywhere in the work area. I also have a ball valve on the outlet port of the compressor so that there will be no bleed down of pressure when the compressor is not powered.

 

[Bert_]

Just install a contactor with the coil tied to the lights. Lights off = compressor off

I wired a church kitchen last year. Plumber installed a circulating pump for hot water. They were talking about a timer or a dedicated switch. I told them I'll just put it on with the lights. Simple and they have been happy.

 

[SouthernIllinois]

If the green light is on, the compressor is energized. If it’s not, the disconnect is open (off)

If the red light is on, the Milwaukee, Dewalt and Stihl chargers are energized. If it’s not, the power to them is secured.

The lights are port & starboard running lights off an old Great Lakes Freighter.



The compressor disconnect switch (pic was before wiring was in place)



The tool battery charging station (panel cover is off because we are still wiring the shed)

 

[no704]

Good time to also set up an automatic drain.

 

[niget2002]

My plan is to install a pool pump timer on mine. I'm going to set an "off" time at 10pm. I'll manually flip the switch to turn it on. If I forget to turn it off, it will turn itself off.

 

[mm08822]

My plan is to install a pool pump timer on mine. I'm going to set an "off" time at 10pm. I'll manually flip the switch to turn it on. If I forget to turn it off, it will turn itself off.

Check the hp rating of the time clock.

 

[niget2002]

Check the hp rating of the time clock.

The one I'm looking at supports a 40A load.

 

[Ultradog MN]

You can buy a "Compressor Minder".
Wear it on your belt.
The two cables are taped to your testicles and the white probe pushed into your urethra.
Strong voltage is applied if you stray more than 50' from the compressor.

 

[mike93lx]

The one I'm looking at supports a 40A load.

That's not the same as a HP rating.

For example, a 50a 6-50 plug is only rated for 3hp.

This thread has some info on why there is a difference

hp vs. current rating

why on many contactors or switches, they give you a hp. rating and also the max. current. and the flc for a motor matching the hp rating is way lower than the max. current rating for the switch? we surmise here that it is factoring in the start up current, but would like to know if someone...

forums.mikeholt.com

 

[rust in the eye]

If the compressor uses a starter/contactor, it's very easy to switch the control power at the light switch.

If it's just a line-start pressure switch on the machine, then you may as well train yourself to switch it locally, or kick off the breaker when you close up the shop.

I've been told that breakers should not be used as a switch. They certainly aren't designed as such.

 

[Norcal]

The one I'm looking at supports a 40A load.

Ampere rating & HP rating are not the same.

 

[dchawk81]

If the green light is on, the compressor is energized. If it’s not, the disconnect is open (off)

If the red light is on, the Milwaukee, Dewalt and Stihl chargers are energized. If it’s not, the power to them is secured.

The lights are port & starboard running lights off an old Great Lakes Freighter.



The compressor disconnect switch (pic was before wiring was in place)



The tool battery charging station (panel cover is off because we are still wiring the shed)

The Edmund Fitzgerald?

 

[rooster59]

As long as I shut the ball valve on the compressor it won’t run when I’m gone. It’s now a habit.

 

[MFortie]

I did what you suggested (relay off a light switch), except I sourced the 120v off one of my banks of lights. I always shut off my lights when I close up the shop, so the comp is definitely off.

In my shop I have three bays. Each bay has a bank of 4 lamp fixtures. Each fixture is controlled by two switches - two lamps per switch (multiple fixtures per switch). I rarely light up all the lamps, so I tied the comp relay to the least used bank.

 

[wyliesdiesels]

I've been told that breakers should not be used as a switch. They certainly aren't designed as such.

depends on the breaker. some are actually

 

[wyliesdiesels]

The tool battery charging station (panel cover is off because we are still wiring the shed)

ummm yellow is not a permissible color for the grounded/neutral conductor, nor is black for the grounding/equipment grounding conductor

 

[niget2002]

Ampere rating & HP rating are not the same.

Gotcha. Found it:

2 HP, 24 FLA @ 120 VAC, 60 Hz; 5 HP, 28 FLA @ 240 VAC, 60 Hz

The Weg motor on my air compressor is only 3HP

 

[APEowner]

I went with the pilot light solution for both the compressor and the phase converter.

 

[u2slow]

I've been told that breakers should not be used as a switch. They certainly aren't designed as such.

That is more about opening them under load.

Some breakers are marked/designed for switching duty.

Like anything, if it wears out, replace it.

 

[Norcal]

That is more about opening them under load.

Some breakers are marked/designed for switching duty.

Like anything, if it wears out, replace it.

The SWD rating on 15 & 20A single pole breakers is intended for fluorescent lighting, there is also a HID rating available but both those types of lighting are pretty much obsolete.

 

[sparky 1971]

I put switches for both of my compressors near the light switch. The 60 gallon switch is right under the light and the 30 gallon is about 5' away because I am too lazy to get out a bender and piece of EMT.

 

[PoorUB]

My compressor controls are wired to the shop lights. Works great for me. A count down time would be my second choice. A switch by the door is just one more thing to remember. Do some sort of control that you don't have to think about.

 

[jblnut]

I have a bathroom fan timer wired in to control a contactor that controls the entire circuit the compressor is on. It’s rare that I run the compressor longer than 60min but if I need to I’ll go push the button again. I have a 120v light wired to the contactor that lights up when it’s pulled in. If I’m doing air things and see the light is out I go push the button again. No big deal.

 

[Bert_]

I've been told that breakers should not be used as a switch. They certainly aren't designed as such.

Breakers under 60 amp are cheap and easy to replace. You can buy several breakers for the price of a contactor or knife switch.

I use the breaker to control the auger motor all the time on farm bins. Up to 10hp 1 ph motors.

 

[rust in the eye]

Breakers under 60 amp are cheap and easy to replace. You can buy several breakers for the price of a contactor or knife switch.

I use the breaker to control the auger motor all the time on farm bins. Up to 10hp 1 ph motors.

I have to wonder if all the cycling when being used as a switch compomises its intended function. Like most things it works until it doesn't. Consequences of a failed breaker?

 

[Bert_]

The

I have to wonder if all the cycling when being used as a switch compomises its intended function. Like most things it works until it doesn't. Consequences of a failed breaker?

Yes it wears them out. The catch inside gets weak. It will trip before it's supposed to and often you won't be able to reset it.

 

[wyliesdiesels]

I have a bathroom fan timer wired in to control a contactor that controls the entire circuit the compressor is on. It’s rare that I run the compressor longer than 60min but if I need to I’ll go push the button again. I have a 120v light wired to the contactor that lights up when it’s pulled in. If I’m doing air things and see the light is out I go push the button again. No big deal.

no overloads on the contactor for the compressor? does the motor have built-in OL protection?

Is that cordage going into the panel? (white cable top of panel)?

 

[sparky 1971]

Is that cordage going into the panel? (white cable top of panel?

Looks like ancient UF to me. That might have been installed by Abe Lincoln during in apprenticeship.

 

[whateg01]

If your compressor doesn't use a starter then it may be worth it to add one. A 5ho motor rated relay is basically a starter.

A starter does include a contactor, but a contactor is not a starter. Without the overload, is just a contactor.

 

[jblnut]

no overloads on the contactor for the compressor? does the motor have built-in OL protection?

Is that cordage going into the panel? (white cable top of panel)?

The contactor/timer is on a 50a breaker inside the panel if that’s what you mean by overloads ? The compressor motor also has that annoying little red button on the side that’ll pop if something gets pissy out by the compressor.

Looks like ancient UF to me. That might have been installed by Abe Lincoln during in apprenticeship.

Yes it’s older UF running a 1hp dust collector.

 

[wyliesdiesels]

The contactor/timer is on a 50a breaker inside the panel if that’s what you mean by overloads ? The compressor motor also has that annoying little red button on the side that’ll pop if something gets pissy out by the compressor.

nope. a breaker is not the overload protection for a motor of this size. notice the FLA on the motor nameplate is a lot lower than 50a? the red button on the back of the motor is part of the overload assembly in the motor however some motors do not have this integral overload protection so it needs to be provided with the contactor aka starter. it would go below the contactor then the motor connections are terminated on the load side lugs of the overload

the breaker is solely for short circuit and ground fault protection. it will not protect the motor or wiring.