Hi guys I’m trying to wire a night switch on my air compressor. I have a 5hp motor on a magnetic starter. Would a regular light switch between the pressure switch and the magnetic starter work ? It’s a 220v single phase set up. Just would like a switch for safety as the breaker is out of hand. Thanks.
Night switch on air compressor
- Thread starter Tapdataz
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wyliesdiesels
Well-known member
What do you mean "the breaker is out of hand"?
yes you could use a snap-switch but make sure its rated for 240v
yes you could use a snap-switch but make sure its rated for 240v
ddawg16
Well-known member
I can relate.....I got complaints from neighbors because I forgot to turn off my noisy 'oilless' compressor.
Use a standard photo sensor switch to activate a relay putting power to your compressor.
rlitman
Well-known member
Assuming you actually have a magnetic starter, then yes, the switch wouldn't need any special current rating, since the pressure switch would only see the current needed to power the contactor coil.
MatBirch
Well-known member
Does your pressure switch not have an On/Off lever switch?
Otherwise, yes any switch in the control side of the contactor that's rated appropriately should work.
By doing that, the OP would have to start the compressor every time the pressure went down, in most cases that would mean start the compressor & wait for the safety valve to pop off, which is why we don't have 3-wire control for air compressors.
No, the 'start' button hands over control to the pressure switch. 'Stop' disables the pressure switch from starting the comp. That's how we run our machines at work... maybe there's a control relay in there, I forget.
^^ I think the start button is magnetically held on (closed) , the off power button disengages (opens) the on power button,as would a power failure .
If someone wants a simple way to shut down a compressor at night, a relay wired into the control wiring of the mag starter & controlled by the shop lights or a selector switch also wired into the starters control circuit would be simple and easy.
Wrench97
Well-known member
As long as it's a 120v coil on the mag starter just wire a normal switch in series with the pressure switch circuit, mines been like that for over 20 years.
alfredeneuman
Well-known member
The same is true for a 230V compressor. You just need to have a switch rated for 120/277V instead of 120 V only. The switch only needs to be a single pole.
nadogail
Well-known member
IMHO, I imagine that all that is required is a single pole, single throw switch in series with the contator coil winding.
For those with any knowledge of motor control circuits, it should be elementary. Any one who can "Hot Wire" a car probably has the required skills.
My own compressser has a lever on the pressure switch. I also the option of pulling the plug from the wall receptacle.
For those with any knowledge of motor control circuits, it should be elementary. Any one who can "Hot Wire" a car probably has the required skills.
My own compressser has a lever on the pressure switch. I also the option of pulling the plug from the wall receptacle.
ddawg16
Well-known member
I just used a switch rated for 240Vac @ 20A.
juddspaintballs
Well-known member
I also had mine on a switch rated for 240v at my last house. I put the switch next to the garage light switches and turned it off anytime I went inside. I had a pressure switch go bad one time when I wasn't home and the compressor ran for a few hours. Never again.
sz0k30
Well-known member
Why bother with a switch at all? I have a ball valve right outside the tank. When I/m done using the compressor I just turn off the valve - no air going anywhere, no compressor cycling.
Like Judd said, pressure switches go bad, contactors weld closed, OLs go bad etc.
ddawg16
Well-known member
I need to install a 240Vac light near the switch so it will get my attention if it's on. I have a bad habit of forgetting to turn it off.
Luckily, my system is tight...as long as a hose is not plugged it, it will stay pressurized for weeks.
exranger06
Well-known member
I have a 240V rated toggle switch for my compressor. I also have a 120V indicator light to remind me if it's on. The light is on anytime the toggle switch is on, whether the compressor is actually running or not. I just had to run a neutral wire to the light for 120V. Attached are pics of the switch and light, and a crude wiring diagram of how it's hooked up.
Attachments
ddawg16
Well-known member
A single pole switch would also work....
Thanks for the suggestion....I forgot I have a neutral in that box....but my box is only a single wide.....
I guess it's a trip to the big box store....
exranger06
Well-known member
If you used a single pole switch, the light might turn on even if the toggle switch is off. If the pressure switch closes, the voltage from L2 would go through the coil and through the pressure switch, making the indicator light up. Using the double pole switch like I did prevents that from happening.
Milton Shaw
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- Feb 11, 2011
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Some pressure switches have the unloader on them. If the compressor is cut off besides from the from the pressure switch, the compressor would be trying to start next time with full head pressure. That may or not be a problem but would cause hard starts. and could trip overloads. I used a motorized ball valve wired to the lights circuit to isolate my compressor from the air lines and prevent it from ever running when lights are off.
rlitman
Well-known member
I do something similar. A night switch that disables the pump doesn't deal well with leaks in your system (and if you have a QD somewhere, you have a leak somewhere). If I switched the pump off and left, most likely I would have to wait an entire pump cycle every time I turn the switch back on, since the tank would empty itself after a few days (it's a big tank). With the motorized valve, I just open the valve, hear air rushing in to charge the lines, and go.
I will say that the motorized ball valve is kind of harsh on my regulator, because of that rush of air every time I open it.
In my case, I have a wifi relay controlling the ball valve, and can control it from a number of ways. That way, when someone goes into the garage just to get something from the freezer, it doesn't open the valve when the lights come on. And I can also turn it on when I'm using one of the outdoor hose reels.
I put a switch in line with the 120v coil side of my mag starter. It already had a switch on the starter box, I simply added another switch. Right by the door of my shop I have 3 switches, lights, compressor and 3ph rotary converter. When I leave i turn everything off. Simple clean and easy.