Hello. Long time lurker here with a question I can't seem to find any info on. I have a Champion 80 gallon 7.5 hp compressor and I would like to add an electric fan to it to help with cooling. My question is can I hook it up to the magnetic starter somehow so that it comes on with the compressor? Any help is greatly appreciated. Thanks.
Adding an electric fan to an air compressor question.
- Thread starter KENWIL138
- Start date
ahazi
Well-known member
The proposed arrangement will not help much. You need to have the extra fan working until the temperature is reduced. Having the fan work only when the pump is on will do very little and will require a much bigger fan. You can use a thermostat that is attached to the motor frame to set up the starting temperature for turning on the fan. Alternatively, just leave the fan on when you expect heavy usage.
I have a 5HP 2 stage compressor feeding an 80 gallon tank and it was used heavily in the last 2 years running some pretty big jack hammers for excavation. I put an extra fan to cool the motor and the pump. The compressor was running for long periods of time with relatively short breaks, all is well and I am done with the heavy construction work.
Ariel
I have a 5HP 2 stage compressor feeding an 80 gallon tank and it was used heavily in the last 2 years running some pretty big jack hammers for excavation. I put an extra fan to cool the motor and the pump. The compressor was running for long periods of time with relatively short breaks, all is well and I am done with the heavy construction work.
Ariel
engineer2
Well-known member
Yes, but why do you think you need one? Hot climate or heavy usage come to mind. Plenty of Champion compressors work fine without one.
One way to do it is to get an 8" axial fan. Simple wiring if you get a 230 VAC one. Yes, you can wire it to the starter contactor coil terminals. Ideally you would wire it to the incoming power in series with a temperature switch mounted to the discharge line and have it run when the temperature exceeds lets say 150°F.
One way to do it is to get an 8" axial fan. Simple wiring if you get a 230 VAC one. Yes, you can wire it to the starter contactor coil terminals. Ideally you would wire it to the incoming power in series with a temperature switch mounted to the discharge line and have it run when the temperature exceeds lets say 150°F.
DeltaWye
Well-known member
If your motor and the fan you want to use are both 240 volt, single phase then you could tap off the load side of the starter. Just add a fuse or circuit breaker ahead of the fan.
If the voltage is different and if your starter has a normally open auxiliary contact, then it's simply a matter of running power to the fan through it. I'm going to be doing something similar but will be using a timer to keep the fan running for a few minutes after the pump cycles off.
If not then it gets more complicated. Posting pictures of your starter, pressure switch (inside, showing how it's wired) and any wiring diagrams will help.
If the voltage is different and if your starter has a normally open auxiliary contact, then it's simply a matter of running power to the fan through it. I'm going to be doing something similar but will be using a timer to keep the fan running for a few minutes after the pump cycles off.
If not then it gets more complicated. Posting pictures of your starter, pressure switch (inside, showing how it's wired) and any wiring diagrams will help.
Well the reason I was wanting it is hot climate (100-110 degrees here in summer) and was to actually be mounted on the outside of the aftercooler I installed. Plus I love little projects like this. 
I was thinking of adding it to the starter wiring I just wanted to be sure because I think I read somewhere at one time that the starter is rated for the motor and the fan could be an extra load it wasn't designed for or something along those lines. Make sense?
I was thinking of adding it to the starter wiring I just wanted to be sure because I think I read somewhere at one time that the starter is rated for the motor and the fan could be an extra load it wasn't designed for or something along those lines. Make sense?pcmeiners
Well-known member
" that the starter is rated for the motor and the fan could be an extra load it wasn't designed for or something along those lines. Make sense?"
No, the fan would only add a small amount of amperage especially at 220v.
No, the fan would only add a small amount of amperage especially at 220v.
manwithtools
ALLIANCE MEMBER
How can you say this without knowing what the fan requirements are? It's incorrect to advise this without knowing all the information regrading the setup.
Motor starters and overloads are not designed to start / protect more than one motor.
manwithtools
ALLIANCE MEMBER
This is correct, adding the fan to the output of the starter is not the correct way to do this. What is the amperage of the fan? Does it have integral overload protection?
brianpgriset
Well-known member
I've run a small 120v Pabst EBM fan by running a separate plug through the pressure switches extra set of contacts. You have to have the extra 120v plug nearby but most of our shops do. I've had no problems with this setup for over 5 years.
You can do it via a relay and feed from motor with a timer for the fan .
Best way is a thermal sensor so fan cycles purely on temp and independent to compressor. I done this for mine when put it in small leen-to on back wall of shop.
Less thermal stress is never a bad thing . I had 2 fans, one for machine and one as extractor in wall .
Best way is a thermal sensor so fan cycles purely on temp and independent to compressor. I done this for mine when put it in small leen-to on back wall of shop.
Less thermal stress is never a bad thing . I had 2 fans, one for machine and one as extractor in wall .
I actually do not have the fan yet. I figured it would have to be 220v since the compressor is. The only reason I really wanted it running while the compressor is was so that it would blow air across the aftercooler and reduce temps even more than the pump pulley fan does. Heck maybe I'll just put a fan I can just turn on manually plugged into the wall. 
MacMcMacmac
Well-known member
There might be auxiliary contacts on the side of the starter, as was stated in an earlier post. If not, they can be purchased and installed with little cost and effort.
If you want to get fancy you can use these contacts to trigger a time delay relay with which you can set any post-run cooling cycle you want.
If you want to get fancy you can use these contacts to trigger a time delay relay with which you can set any post-run cooling cycle you want.
ovrrdrive
Well-known member
Mounting it on the aftercooler is a great idea. The air in the tank will hold heat long after the pump has shut off. If it was a intercooler it wouldn't make as big of a difference if it was running after the pump shut off but it would still help. If I was doing it on the aftercooler I would most likely look for a thermostatically controlled switch instead of a timer. The temps are more static on the output than they would be on the head or on a intercooler.
More cooling is never a bad idea. (waits patiently for some smart *** to come up with an example to the contrary... lol)
More cooling is never a bad idea. (waits patiently for some smart *** to come up with an example to the contrary... lol)
manwithtools
ALLIANCE MEMBER
No aux contacts on that starter, they may be available to add. Yep, looked it up; C320KG1 is the part number.
I would use a separate 120 volt circuit (outlet) with the aux contact to activate a relay that turns the fan on and off. An off-delay relay would be ideal, set it to run after the compressor shuts off for a few minutes.
Perhaps look at an automotive electric radiator fan powered by a 12 volt power supply - fairly inexpensive. I bought all the pieces to do this, but have not done it yet. They move a lot of air very efficiently.
I do like the idea of a thermo switch that would run the fan any time the compressor was above a preset temperature better than the aux contact / relay solution.
I would use a separate 120 volt circuit (outlet) with the aux contact to activate a relay that turns the fan on and off. An off-delay relay would be ideal, set it to run after the compressor shuts off for a few minutes.
Perhaps look at an automotive electric radiator fan powered by a 12 volt power supply - fairly inexpensive. I bought all the pieces to do this, but have not done it yet. They move a lot of air very efficiently.
I do like the idea of a thermo switch that would run the fan any time the compressor was above a preset temperature better than the aux contact / relay solution.
I appreciate all the replies. I don't really want to have it on a temp sensor just because this fan would be to cool the aftercooler more than a fan for the compressor pump itself. That's why I was wanting it to run while the compressor is running. Not against having it run for a min or two after the compressor shuts off but it needs to run when compressor starts. I am interested in the 12 volt idea. Would the 12 v power supply attach to the starter somehow? Thanks again.
Just add a 230V breaker next to the contactor (starter) housing and hardwire to the 208/230V fan. Use the same wiring methods you see for the compressor. My view is if you need to ask this stuff on a forum, youre probably much better off paying a friendly local electrician, since you
This is done all the time inside a typical outside AC condenser unit, except your fan wiring isn't protected inside a single enclosure. So a breaker or fuse needs to be added. What fan and housing are you gonna use?
This is done all the time inside a typical outside AC condenser unit, except your fan wiring isn't protected inside a single enclosure. So a breaker or fuse needs to be added. What fan and housing are you gonna use?
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I agree that an electrician will be the best idea if I feel that this is way over my head. I just wanted to ask and see how involved any of this is. I don't have any particular fan picked out just yet. At first I figured it would have to be a 220 volt but now there is 12 volt and 120 volt that have also been mentioned. I honestly like the 12 volt idea since that particular style fan (radiator cooling fan) would probably fit perfect on the aftercooler.
manwithtools
ALLIANCE MEMBER
que, you no habla HVAC condensers.
apollo11
Banned
I hard wired my compressor and a 12v fan w/adapter to mine. Flip the switch, both turn on and off. Compressor cycles normally but fan is continuous.
no its OK
Condenser fans are usually all fractional HP motors PSC type, yes they are internally protected against thermal overloads. Most are 208/230 and are safe to connect to the starter. Since the fan wiring will be unprotected and lighter gauge it should be fused just after the starter. The fans wiring determines the fuse/breakers rating not protection for the motor. Any electrician will easily know how to wire all this in accordance to local regulations. Fan blades and UL listed motors can be had for under a hundred. Many of these motors are universal replacement types and have 3 speed taps / amperages.
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pcmeiners
Well-known member
From years of experience I know a fan suitable for an aftercooler is fractional HP, an extremely small load. You have little experience with aftercoolers or fans or you would not make your comment.
manwithtools
ALLIANCE MEMBER
No, it's not okay. The fan cannot be added to the motor starter/overload combo. You clearly do not understand how that starter and overload work. The overload is set to protect the compressor motor, additional loads are not permitted.
If there was a way to connect the fan to the starter ahead of the overload unit, then it could work as along as the fan wires were protected by fuse or circuit breaker.
If you look at the picture the OP provided, someone has attached a wire to the starter at 6/T3. This is not permitted because the device is not dual rated for terminations. In other words, only one conductor per terminal is allowed - the overload input bar is the one conductor.
It looks like the are tapping one hot leg of the 240 and ground, this is also not allowed. The ground wire is now current carrying.
Your analogy to an AC compressor and fan is incorrect. In an AC unit the contactor and overload are separate. The compressor has it's own overload and the fan is integrally protected. The contactor feeds both motors, but the overload is stand alone. In the OP's case the contactor and overload are connected as a rated assembly.
If there was a way to connect the fan to the starter ahead of the overload unit, then it could work as along as the fan wires were protected by fuse or circuit breaker.
If you look at the picture the OP provided, someone has attached a wire to the starter at 6/T3. This is not permitted because the device is not dual rated for terminations. In other words, only one conductor per terminal is allowed - the overload input bar is the one conductor.
It looks like the are tapping one hot leg of the 240 and ground, this is also not allowed. The ground wire is now current carrying.
Your analogy to an AC compressor and fan is incorrect. In an AC unit the contactor and overload are separate. The compressor has it's own overload and the fan is integrally protected. The contactor feeds both motors, but the overload is stand alone. In the OP's case the contactor and overload are connected as a rated assembly.
manwithtools
ALLIANCE MEMBER
I made the comment because I operate a UL508A control panel fabrication facility. I know what UL permits to be connected to the motor starter / overload combination and what they do not.
Hmm a sheet metal fabricator ...hardly an expert on commissioning a large single phase compressor ...please cite the UL regulation that prohibits a fan load of around 0.3 KVA or less to be added to this beast of a starter? UL cares about limits being exceeded and such on their listed component , NOT what wires go where, that's the NEC! so a local electrician would assure no rules are being violated. Remember the OP will not apply to UL to certify his installation. YOU on the other hand as an OEM , couldn't change a screw size without consulting a UL inspector. Please don't confuse them*.
* perhaps re-read UL508A article 1.4
1.4 An industrial control panel does not include an evaluation of the controlled equipment such as motors, heaters, lighting, and other loads connected to power circuits. Unless specifically noted on the wiring diagram of the industrial control panel, an industrial control panel does not include equipment mounted remotely from the panel and connected via a wiring systems or equipment field installed on or within the industrial control panel.
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manwithtools
ALLIANCE MEMBER
You obviously do not know what a UL 508A panel shop is or does. I'm not a sheet metal fabricator (although I do modify a lot of metal enclosures) and I'm not an OEM that submits products for UL approval.
We assemble and wire control panels using UL listed or recognized components and then WE apply a UL label that we control to the completed controls package. We do not consult a UL inspector, they periodically visit us unannounced to inspect our certification process and spot check our work.
I think you are a bit far off track on the UL 508A article 1.4 terminology. I'm very familiar with the article and what it's stating, you are not interpreting it correctly.
"An industrial control panel does not include an evaluation of the controlled equipment such as motors, heaters, lighting, and other loads connected to power circuits." What that statement means is that we don't and cannot evaluate the items such as motors, heaters, etc. that are outside the cabinet. That's a field inspectors job, we are responsible for everything inside the cabinet and it's adherence to UL, NFPA and NEC codes and the design of the control circuit and it's suitability to control the intended loads. That means I'm responsible for motor starter and overload sizing for the motor circuits.
Here's a picture of a portion of a little cabinet we built recently; 600 amp main feed with over 45 motor starters and VFD's.
One motor per overload, this is plainly stated in UL 508A Article 34.3.1: "Motor overload protection shall be provided for each individual motor circuit."
In this case the intended load is a motor (Compressor.) and it needs it's own overload because that motor does not have integral overload protection. If you add another motor (fan) then it needs a separate overload, it can be integral to the fan motor, but it cant be wired to the compressor motor overload.
This really needs to be moved to the electrical section of the forum.
We assemble and wire control panels using UL listed or recognized components and then WE apply a UL label that we control to the completed controls package. We do not consult a UL inspector, they periodically visit us unannounced to inspect our certification process and spot check our work.
I think you are a bit far off track on the UL 508A article 1.4 terminology. I'm very familiar with the article and what it's stating, you are not interpreting it correctly.
"An industrial control panel does not include an evaluation of the controlled equipment such as motors, heaters, lighting, and other loads connected to power circuits." What that statement means is that we don't and cannot evaluate the items such as motors, heaters, etc. that are outside the cabinet. That's a field inspectors job, we are responsible for everything inside the cabinet and it's adherence to UL, NFPA and NEC codes and the design of the control circuit and it's suitability to control the intended loads. That means I'm responsible for motor starter and overload sizing for the motor circuits.
Here's a picture of a portion of a little cabinet we built recently; 600 amp main feed with over 45 motor starters and VFD's.
One motor per overload, this is plainly stated in UL 508A Article 34.3.1: "Motor overload protection shall be provided for each individual motor circuit."
In this case the intended load is a motor (Compressor.) and it needs it's own overload because that motor does not have integral overload protection. If you add another motor (fan) then it needs a separate overload, it can be integral to the fan motor, but it cant be wired to the compressor motor overload.
This really needs to be moved to the electrical section of the forum.
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With all the discussion above I would think the best way to handle this is some type of sensing switch that can operate off a separate 120v line. A search for current sensing relay turned up a lot of options.
http://www.productsforautomation.co...MIucfoso6v1gIVBo5pCh2uFA2FEAQYCCABEgLeP_D_BwE
Something like the above (just am example from my search) would let you connect just about any fan without ever taping into the actual compressor wires.
http://www.productsforautomation.co...MIucfoso6v1gIVBo5pCh2uFA2FEAQYCCABEgLeP_D_BwE
Something like the above (just am example from my search) would let you connect just about any fan without ever taping into the actual compressor wires.
engineer2
Well-known member
manwithtools
ALLIANCE MEMBER
In other words, I am responsible for all the components inside the panel but I can't control what someone might ultimately connect to it, therefore my listing does not cover anything outside the cabinet. But I must design to the expected loads
This looks like a good current sensing option.
http://electronicaircleaners.com/aprilaire-51.aspx
http://electronicaircleaners.com/aprilaire-51.aspx
bingo just like article 1.4 says. But yet you've somehow determined a tiny fan externally mounted has overloaded the system....
A little detail you seem to forget, the OP doesn't have to maintain ANY UL listing unlike you.
Your lack of comprehension of the English language is mystifying..
engineer2
Well-known member
manwithtools brings up a good point. Plus there is no reason to connect anything to T1, T2, or T3.
which is?
nothing he said would be in violation of UL. The fan wouldn't be depending on the starter for protection and would NOT defeat the overload protection for the compressor motor. Someone has UL tinted blinders defeating good sense. He cant seem to think outside the box misinterpreting HIS requirements to UL. I suggest the OP contact a local electrician to get sound advice.
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Lelandwelds
Well-known member
Why fan cool an aftercooler? The ones I have seen are within 10°or 15° over ambient just one third into the cooler. The pumps only get about 25° over ambient. The tank was at ambient. Why fan cool if you already have excess capacity?
If the answer is "because I can", please continue. I am guilty of the same thing just with a different subject.
And, yes, I am the guy who keeps taking the temperature of everybody's beer with the laser.
If the answer is "because I can", please continue. I am guilty of the same thing just with a different subject.
And, yes, I am the guy who keeps taking the temperature of everybody's beer with the laser.
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engineer2
Well-known member
If you are controlling a device such as a fan, there are more logical places to connect it. No need to connect to the motor wires. Just use the extra contacts on the pressue switch. Pick up power from L1 and L2. Done.
sure there a half a dozen ways to safely do it, BUT it has to agree with the person responsible to complete the work. DONE