wiring air compressor auto drain to magnetic starter?

[roll_the_dice]

I have had my new air compressor for a month or so now and want to incorporate an auto drain, but only want it to run while the compressor is running. I don't use the compressor everyday and I cut it off when not in use, so I don't want the drain to run while the compressor is off for a day or two at a time.

I have read I can wire the drain into the magnetic starter, but where? Do I wire it into bottom where the motor is wired? Below is a picture of my magnetic starter. Thanks for any help you can provide or if there is an easier way to achieve what I want, I am open to suggestions...Thanks

 

[lakeroadster]

The easiest... put a ball valve on the drain. At the end of each day you use the compressor, open the valve, drain the water, close the valve.

I made a catch can out of an old folgers can filled with kitty litter. put a shop rag over the can, cut a flap in the lid, easy peazy retro fit for less than 10 bucks.

Do you have manual valves to drain the piping?

 

[roll_the_dice]

Thanks for the suggestion. I am also forgetful and want the auto drain to ease my forgetfulness. I have a ball valve, I have had auto drains in the past at work and like them for the convenience...hence the auto drain at home. I am going to plumb the auto drain outside through an exterior wall.

 

[lakeroadster]

Nice Stepside...

Here's a link to the build thread for my orange crate:
https://talk.classicparts.com/threads/lakeroadsters-build-thread-65-swb-step.13928/

 

[MFolks]

Explore the large Diesel trucks drains,they use air for braking, and must keep water out of the lines.

 

[outdoorspace]

I don't know about your wiring. But I installed an auto drain on mine that runs with the motor, got the 240V solenoid on eBay for $25.

I'd guess you'll need to hook the solenoid between the wire from the pressure switch and the other phase.

 

[wyliesdiesels]

You could wire it through an auxiliary contact

 

[engineer2]

If it is a timed drain, it might be better to wire it so it operates whenever power to the compressor is on. Water in the tank takes time to condense, so it's better to have the drain operating the whole time power is on to the compressor.

How to wire it depends on if the auto drain is 120 VAC or 240 VAC.

 

[BillK]

I dont have one at my present shop but in the last building we were in we had an auto drain that worked simply off air pressure changes. It worked fine for 10 years. No electricity needed. If I remember correctly it would drain the tank when the pressure went down to a certain point. I think it drained at the end of the day after we turned the compressor off and the system bled down overnight ?

 

[roll_the_dice]

Explore the large Diesel trucks drains,they use air for braking, and must keep water out of the lines.

I dont have one at my present shop but in the last building we were in we had an auto drain that worked simply off air pressure changes. It worked fine for 10 years. No electricity needed. If I remember correctly it would drain the tank when the pressure went down to a certain point. I think it drained at the end of the day after we turned the compressor off and the system bled down overnight ?

I have looked at those...I think they work off the unloader before the pressure switch...I may end up doing that. When the pump is running it has a small reservoir that holds condensation. When the pump turns off, it releases the condensation. My only concern with that is in my mind, I would still need an auto drain at the bottom of the tank, since the pressure drains I have seen are at the top.

If it is a timed drain, it might be better to wire it so it operates whenever power to the compressor is on. Water in the tank takes time to condense, so it's better to have the drain operating the whole time power is on to the compressor.

How to wire it depends on if the auto drain is 120 VAC or 240 VAC.

That is exactly what I want to do. I don't care either 120 or 240...240 is going to the compressor already...would I just wire the drain into the same lugs as the motor on the magnetic starter?

 

[roll_the_dice]

You could wire it through an auxiliary contact

Explain more.. please. I am a newbie with electric...I know enough to be scared of it...but can follow directions.

 

[roll_the_dice]

Nice Stepside...

Here's a link to the build thread for my orange crate:
https://talk.classicparts.com/threads/lakeroadsters-build-thread-65-swb-step.13928/

Thanks...a work in progress for sure!

I like your truck too...that is a great build thread. I will have to set some time to go through it. I started looking and really like your tail lights! I don't like the hang on kind either...but my gas cap is near that same section...I will have to see if there is room for both.

 

[MFolks]

Aux contacts are just that,a separate switch, not powered by the contactor ,but moving mechanically,when it energizes,lights,or auto drains,as long as the load does not exceed the contacts amp ratings,it should work good.

 

[MFolks]

If the contactor does not have aux contacts,see if a kit can be bought to install one,the heavy duty armature when it moves when energized, will move the aux contacts.

 

[roll_the_dice]

If the contactor does not have aux contacts,see if a kit can be bought to install one,the heavy duty armature when it moves when energized, will move the aux contacts.

Thanks, that is exactly what I am searching for now. Mine doesn't have aux contacts. Below is a picture of my contactor. I think this aux contactor will work Eaton part # c320kg2. I assume it just plugs in to the side of the contactor?

Would it be bad to connect the auto drain to 2T/1 & 4T/2? Obviously it is only energized when the compressor is running.

 

[sberry]

I can and dont. I have valves and t tube thru the wall. On occasion when I read a drain thread I will walk over and kick them open a few seconds till it clears. Ifin I use it a lot more, sometimes not for a month. Mine runs a couple cycles every day and is on 24/7.
Found free old copper tubing, found all the pieces and had to make 1 flare.

 

[engineer2]

BTW, what is the model of the Compressor? The Eaton starter catalog is online and you can get the specifics on your starter C25DNF340. Champion uses these.
A few ideas depending on what you get:

120 VAC plug-in auto drain off of Amazon
Put a switched 120 VAC outlet next to your compressor power switch; 4x4 box with one outlet and a light switch to power the auto drain.
or
Basic setup: 120 VAC outlet near compressor. Unplug the drain when you turn the compressor off (this is what I do.)
or
Pull a white neutral wire to your mag starter box from a 120 VAC circuit or panel. Cut the plug off the auto drain and wire the hot to either the upper red or the black wires, and the other wire to the neutral. The auto drain will power on when you turn on power to the compressor.

220 VAC plug in auto drain off of Amazon
Cut the plug off the auto drain and wire to the upper red and black wires that feed power to the starter. The auto drain will power on when you turn on power to the compressor.

^^Wylie, does this sound correct?

 

[larry4406]

I want to use the pneumatic tsunami moisture minder on mine.
https://www.aircompressorsdirect.com/Tsunami-152-0000/p11942.html

 

[roll_the_dice]

BTW, what is the model of the Compressor? The Eaton starter catalog is online and you can get the specifics on your starter C25DNF340. Champion uses these.
A few ideas depending on what you get:

120 VAC plug-in auto drain off of Amazon
Put a switched 120 VAC outlet next to your compressor power switch; 4x4 box with one outlet and a light switch to power the auto drain.
or
Basic setup: 120 VAC outlet near compressor. Unplug the drain when you turn the compressor off (this is what I do.)
or
Pull a white neutral wire to your mag starter box from a 120 VAC circuit or panel. Cut the plug off the auto drain and wire the hot to either the upper red or the black wires, and the other wire to the neutral. The auto drain will power on when you turn on power to the compressor.

220 VAC plug in auto drain off of Amazon
Cut the plug off the auto drain and wire to the upper red and black wires that feed power to the starter. The auto drain will power on when you turn on power to the compressor.

^^Wylie, does this sound correct?

I have a Champion compressor.

The 2nd option is what I had in mind, but hadn't thought about using the 2 hot wires to have it on the entire time the compressor was HOT, but using the bottom 2 (2/T1 and 4/T2) and only running it when it was actually running. I could try both and see which one suits my needs better.

Thanks!

I want to use the pneumatic tsunami moisture minder on mine.
https://www.aircompressorsdirect.com/Tsunami-152-0000/p11942.html

I really like the Tsunami moisture minder, but does it remove water from the bottom of the tank too or just from the compressor itself? If from the compressor, do you still need to drain the bottom of the tank separately? Or is there a way to achieve both using it?

 

[exranger06]

How do you normally switch the compressor on and off? Do you have a remote toggle switch? If so, you can wire up a 240V auto-drain so it turns on when you have the toggle switch on, regardless if the compressor is actually running or not. It turns off when you turn the switch off.

You would have a wire connected to one hot leg, then it goes through the toggle switch,(***) then it goes through the pressure switch, then to one of the terminals on the coil of the contactor. The other terminal of the coil connects directly to the other hot leg. (***)
To hook up the auto drain, splice in right where the (***) is above (right between the toggle switch and pressure switch) and connect one wire there. Connect the other wire directly to the other hot leg (where (***) is above.)

 

[roll_the_dice]

How do you normally switch the compressor on and off? Do you have a remote toggle switch? If so, you can wire up a 240V auto-drain so it turns on when you have the toggle switch on, regardless if the compressor is actually running or not. It turns off when you turn the switch off.

You would have a wire connected to one hot leg, then it goes through the toggle switch,(***) then it goes through the pressure switch, then to one of the terminals on the coil of the contactor. The other terminal of the coil connects directly to the other hot leg. (***)
To hook up the auto drain, splice in right where the (***) is above (right between the toggle switch and pressure switch) and connect one wire there. Connect the other wire directly to the other hot leg (where (***) is above.)

The electrical panel is right next to the door I use when I leave. I flip the breaker every day when I am done for the day.

 

[exranger06]

Well in that case I would simply get a 240V auto drain and connect it to L1 and L2 on the contactor. The drain will be on whenever the breaker is on, and off when the breaker is off.

 

[roll_the_dice]

Well in that case I would simply get a 240V auto drain and connect it to L1 and L2 on the contactor. The drain will be on whenever the breaker is on, and off when the breaker is off.

Thanks!

I have been investigating the moisture minder pneumatic posted on page 1. I like the idea of no electric and only runs when the compressor runs. I just need to figure out which I want to do...times with power or pneumatic/no power.

 

[engineer2]

On our Champion, the pneumatic moisture minder is connected to the bottom of the tank via a nylon tube. It is also connected to the unloader line, which triggers its operation when the compressor cycles off.

The moisture minder discharge line will spray rusty water, which can make a mess. You need to route it outside, to a drain or to a bucket. No routing outside for businesses, that's a hazardous waste violation. It's funny that the discharge is 99.9% water (unless your compressor is worn out), yet is considered hazardous waste.

 

[roll_the_dice]

On our Champion, the pneumatic moisture minder is connected to the bottom of the tank via a nylon tube. It is also connected to the unloader line, which triggers its operation when the compressor cycles off.

The moisture minder discharge line will spray rusty water, which can make a mess. You need to route it outside, to a drain or to a bucket. No routing outside for businesses, that's a hazardous waste violation. It's funny that the discharge is 99.9% water (unless your compressor is worn out), yet is considered hazardous waste.

I might end up going this route. I saw a video where someone connected the moisture minder to theirs as well. Could be the easiest solution. Does the Champion at your work just have a T fitting on the unloader feeding the moisture minder? Thanks!

 

[wyliesdiesels]

The electrical panel is right next to the door I use when I leave. I flip the breaker every day when I am done for the day.

How far away is the compressor from the panel and is it in sight?

 

[roll_the_dice]

It is only about 18 foot walk from the panel and it is in sight. Going up through the wall, over and back down the wall is roughly 30 feet when I wired the compressor.

 

[The Tool Tyrant]

Since you have a Champion (I assume it has a centrifugal unloader) here is the link for the retrofit kit...
https://www.ebay.com/itm/CHAMPION-C...806918&hash=item4175ff3c9a:g:ebkAAOSw3R1XT03a

 

[engineer2]

Does the Champion at your work just have a T fitting on the unloader feeding the moisture minder?

Yes:
Line from the bottom of the tank
Discharge line
Line from the unloader
I can try to get a pic Monday.

 

[DieselNut88]

If you still want an aux contact the one you listed is normally closed you would need a normally open. Eaton C320KG1. A circuit breaker should not be used as a disconnect device. It will wear out the breaker over time.

 

[sberry]

Yes it will but if he has simple leak free system may be able to start it while pumped up most of the time. If it was close might even really use a service valve on the tank as the nightly shut off and leave it on.
I got 2 comps, demand and backup unit and its always charged when I turn it on, I can isolate either unit by valve so never really need to start a unit with breaker and one has disconnect switch on the starter. I havnt actually breaker started one in years.

 

[roll_the_dice]

Yes:
Line from the bottom of the tank
Discharge line
Line from the unloader
I can try to get a pic Monday.

Thanks, I would appreciate it.

If you still want an aux contact the one you listed is normally closed you would need a normally open. Eaton C320KG1. A circuit breaker should not be used as a disconnect device. It will wear out the breaker over time.

I was curious about NO vs NC. Thanks!

Yes it will but if he has simple leak free system may be able to start it while pumped up most of the time. If it was close might even really use a service valve on the tank as the nightly shut off and leave it on.
I got 2 comps, demand and backup unit and its always charged when I turn it on, I can isolate either unit by valve so never really need to start a unit with breaker and one has disconnect switch on the starter. I havnt actually breaker started one in years.

My system is leak free...so when I turn on the breaker, it is just turning on the juice...the compressor hasn't ever started with the flip of the breaker except the very first fill. I was on vacation for 10 days recently and I shut it off and when I came back and flipped it on, it was still pumped up and did not turn on.

 

[Matt Matt]

A Auto drain at the bottom of the tank would be a nice feature. But solenoids sometimes tend to get jammed with dirt and rust particles, Having Chiller and flotation bleed before the tank reduces majority of the condensation in my tank year round. My shop is air-conditioned though. The bottom of my tank I’ve added about 1 foot of brass ****** to a ball valve. I empty my tank moisture three or four times a year and I get maybe 1/4 cup.

 

[matt_i]

One way to do this is to use a control transformer 240:120 and then an ice cube relay. You wire the control transformer off L1-L2, the top side of the contactor. A 50VA transformer is pretty std, although 100VA will get you about 1 amp which would be better IMO. You should research the current draw of the intended auto-drain first.

The ice cube relay of about 15A ampacity (std) will have its coil wired to T1, T2 on the bottom side of the contactor. So its energized at the same time as the motor.

You will also use the 120vac present to work your auto-drain. That's going to wire thru an NO contact on the ice cube relay.

In essence this is the same as adding an aux contact to the existing motor starter.

Drawing will have to wait a bit. Be back a little later.

 

[matt_i]

Here's what I had in mind. Would also be good to put a glass fuse on the secondary (120vac) to avoid melting down the transformer in case of short circuit or overload.

 

[Matt Matt]

I’ve also done it this way with a timer relay. You can set a bleed time at the beginning of every cycle.

 

[roll_the_dice]

One way to do this is to use a control transformer 240:120 and then an ice cube relay. You wire the control transformer off L1-L2, the top side of the contactor. A 50VA transformer is pretty std, although 100VA will get you about 1 amp which would be better IMO. You should research the current draw of the intended auto-drain first.

The ice cube relay of about 15A ampacity (std) will have its coil wired to T1, T2 on the bottom side of the contactor. So its energized at the same time as the motor.

You will also use the 120vac present to work your auto-drain. That's going to wire thru an NO contact on the ice cube relay.

In essence this is the same as adding an aux contact to the existing motor starter.

Drawing will have to wait a bit. Be back a little later.

Thanks I appreciate it....especially the drawing. It is amazing the knowledge of the members of this board, especially for electrical. I have learned so much by just searching this board or a google search and that usually leads back here anyway!

 

[engineer2]

Auto drain pics.
The brass device leading into the auto drain is a strainer. It came with the compressor.
We also have a timed drain for redundancy and because we already owned it. McMaster Carr 9831K12

 

[roll_the_dice]

Auto drain pics.
The brass device leading into the auto drain is a strainer. It came with the compressor.
We also have a timed drain for redundancy and because we already owned it. McMaster Carr 9831K12

Thanks, that helps a lot! I am probably going to do that....seems like the best way to achieve what I want.

I like how you guys have the oil drain too. I plan on doing that when I change the oil. Will make it easier.

 

[Dagny]

We wire a lot of farm shops and I like to put all the control wiring on the light circuit in case a hose blows or another leak comes about. also allows for an auto drain on properly sized fuses. a solonoid valve and time delay relay allows the drain to open for 2 or 3 seconds every time the compressor starts.