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Compressors?? perfect air? Post New Topic | Post Reply

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daniel kempton Posted: Mar 08, 2008 03:29 PM	Compressors?? perfect air? I'm in the process of building my first rig, I've read alot from people who wish they would have spent the extra money in the begining instead of later. Which is one of the reasons that I've upgrade to the e-30, but the main complaint that I see is everyone wants more air. I've spoken to several different distributors and there advice ranges from 5hp, 7.5hp and 10hp. all the way from 40gallons up to 120 gallons. What do I need??? Is it power or capacity that matters? Would 2 5hp 60 gallon tanks plumbed together be better than 1 10hp 120 gallon tank? Just looking for some good ideas. I'm putting it together in a 16ft box truck, and I'm going with shore power. How much cfm? What psi? Thanks
Arville Brown Posted: Mar 08, 2008 05:07 PM	Check out eaton compressor they have great products and raelly good price I have had my compressor for 5 years with no problems
Linerman Posted: Mar 08, 2008 05:50 PM	You just need a compressor that can give a min. of about 120 psi and 15 cfm's. Since your running an electronically driven proportioner you really don't need a huge compressor. Just make sure that the compressor you do choose isn't gonna run constantly so probably one 5hp 60 gal. would do. Some people run even smaller compressors without any problems.
Gerry Wagoner Posted: Mar 09, 2008 03:44 PM	You won't be able to to run anything beyond a 5-hp on shore power. oG
Tim O'Keefe Posted: Mar 09, 2008 09:17 PM	I believe Circle-D has a 10hp he runs on shore power. I know others with 7.5hp with good results too. Eaton has a constant run feature so once the motor starts it stays running thus reducing the huge initial amperage draw. Tim Granite State Spray Foam Co.
daniel kempton Posted: Mar 09, 2008 11:42 PM	I checked out eaton, seems like they have great prices and all of the reviews that I have read looks like they keep their customers happy. I guess I'm going to go with a 5hp two stage 60 gallon, my box truck has two 20gallon tanks underneathe the box, I was thinking about plumbing them in too, to give me a 100 gallon capacity. I'm planning on getting a refrigerated air dryer too (from eaton). Are they needed? I was advised to not build without one. It's almost as expensive as the compressor.
philip mullins Posted: Mar 10, 2008 01:39 AM	i also give props to eaton. good product. good price. and unmatched customer service. i use thier 7.5 on shore power with no probs. learn about different viscocity oils for different seasons. it realy does make a difference. in ur area i would recomend that you spend the money on the ir all season synthetic oil since it can go from 30 degrees to 90 12 times in a single day there. terry has an e30 and he uses one of those cobalt compressors with no issues. he saved several hundred dollars and if he ever does have a prob he will pull up to any lowes and exchange it.tx
Tim Trott Posted: Mar 10, 2008 07:10 AM	I bought a 10hp rotary screw single phase compressor with air conditioned dryer and 120 gal holding tank from Eaton Compressors. It's large and expensive 5-plus grand- but fit into the front of our 16 ft trailer. It runs on "shore power" through a 130 Amp cable connected to a subpanel in the trailer. We have an assortment of 100 amp breakers to patch into a scenario of circut boards. The compressor is the most quietest one i've ever heard, you can have a conversation leaning on it without yelling. The air supply is more than sufficient to get the job done.
Circle-D Posted: Mar 10, 2008 12:58 PM	Yes, as Tim says, I run a 10 hp single phase 120 gallon from Eaton on shore power with no problems. I would recommend them highly. I will be buying another for my shop soon.
quentin Posted: Mar 11, 2008 09:02 AM	Eaton is near me and I was looking at them too. If anyone is in the area to pick one up instead of having it shipped, drop me a line. Working on an E-30 setup myself and have a 29.5ft trailer I am modifying to put it all in. Hoping to have it set and ready when the season hits back in a month!
Terry Adams Posted: Mar 11, 2008 10:34 PM	like trout said I've been using a kobalt for almost 3 years now. couple minor issues, hose to cutoff broke, cutoff switch went out, used the one off my craftsman till they sent me one the next day. Its a 5hp peak 3.5hp running. Does all I need using shore power - air drier, e-30, ipm02 pumps and fusion ap. I have less than 1,000 in both air comp and air drier.
Gerry Wagoner Posted: Mar 16, 2008 10:54 AM	It would help to establish the parameters of "shore power." Running a 10hp electric motor requires 3-phase and unless you work exclusively with industrial customers you won't find that level of power on many jobs sites. The same goese for a "true" 7.5 hp. electric motor - they require 3-phase power. How are you pulling 100-130 amps of 220 into your trailer? Most temporary electric services are doing good to have 50-60 amps. regards, oG
Circle-D Posted: Mar 16, 2008 09:50 PM	Hi Olger, I respectfully disagree with you. My Eaton compressor runs a single phase 10 hp motor. By the time I arrive at the site the permanant power and wiring are already installed and it is generally a 200 amp service now a days. I get power to my trailer via a 3 wire cable I purchase from Trystar cable in MN. It consists of 3 separate #4 copper cables and is rated at 125 amps at 70*. It is soft, flexible and easy to handle. Attach to it a 100 amp breaker and plug into the customers panel. It may not be the best but it works for me.
Terry Adams Posted: Mar 17, 2008 11:35 PM	Down here there is no difference between temp power and perm power. How are they choking it down where you're at ?
philip mullins Posted: Mar 18, 2008 11:27 AM	eaton and several other manufacturers strongly recomend that peeps DO NOT run thier compressors on a generator. i do not know what a true 7.5 horse is or how it differs from other 7.5's. but, my eaton 7.5 with 120 gallon tank pushes 32 cfm @ 120psi. and it pulls about 330 amps on startup. this is possible on single phase 220 due to the use of a starting cappacitor. i also have a genset for my rig. i have never installed it. it is on a trailer incase i ever need it. never have.
Posted: Mar 20, 2008 12:27 PM	Hi there, If I am reading your post corretly, you are saying that your compressor on start up is pulling 330 amps right and are using a start up cap?. I ask because we are having a problem with our rig where when the compressor starts up (10 hp atlas copco) the draw is so extream that the volts drop to 170 then once the gen sees this picks up the pace and spikes it to 290+ then levels back out at 230. This spike is killing our equipment and nobody seems to have an answer. I know that we should switch to a continuous run compressor but if a start up cap will work then I would go that route. So the question is again,do you run a cap with you system and if so has it solve this problem? Thanks Tyler
Tim O'Keefe Posted: Mar 20, 2008 08:23 PM	Northstrar, It sounds like you need a bigger generator. If it is drawing down like that it means the engine doesn't have enough power to turn the alternator end as the power draw comes on. Then it overrevs and the resultant voltage spike. The volts and hertz are both factors of the revolutions of the engine. Most generators have an under and over rev safety feauture but it doesn't sound like yours has that. I rented a generator once for a large compressor and when it would draw down on startup the generator would bog and shut off. I wouldn't waste money on trying to make the compressor work. You are going to cook something sooner or later! Tim Granite State Spray Foam Co.
quentin Posted: Mar 21, 2008 10:06 AM	Save yourself the trouble all down the line and look at an Eaton screw compressor. I thought pretty hard on it and it will draw less power, be more consistent and last a LOT longer than a pump compressor. It is CFM not a ton of pressure you need and they are the way to go on that. You can then keep the trigger hammered and as long as your heaters hold up you won't need to wait for the compressor to recover. Then it is how long YOU can spray without a stop and not the equipment.
Posted: Mar 24, 2008 09:12 AM	Hi Tim, We are running with a 40kw gen in the truck at the moment, which does not have a soft start function on it. But we did connect the system to out other truck gen unit that does have a soft start (40kw aswell) with the same result. You can have everything else disconnected and run the compressor with the same spiking results. So possibly we could have a too small of a gen but on paper it shows that we have ample power to boot. So again I will pose the question and see if anybody has used or uses a capacitor to aid with the compressor start up. Thanks Tyler
John Shockney Posted: Mar 24, 2008 04:01 PM	? Are you running single phaze or 3 phaze? That will effect the way a capastor or capastors would be wired into the system and if it would help. And I know that power companys use very large caps. in their power grid to reduice voltage spikes. And yes your 40kw gen shouldn't drop that much or spike that high the governer should mantain constant rpm. generator governers have several adjestments including speed and Sensitivity you may want to take the gen to a service center and have it load tested make shure the center that you take it to has a load bank big enough to fully test your generator. The gen info comes from 15 years of working on high end RV's, as an electric and hvac tec. Hope this is helpfull Thanks John AIRPRO hvac & spray foam
Michael Flander Posted: Mar 25, 2008 10:38 AM	Wouldn't a capacitor of this size be just as expensive as making the change to a constant run compressor(You would really just have to change the pump to one with head unloaders). I don't know much about caps, but a quick google search showed them to be pretty spendy...
quentin Posted: Mar 25, 2008 11:33 AM	Any capacitor that big would be a huge cost! One reason I am looking at an Eaton screw setup is the constant run ability of it and the power requirements for the amount of air are a lot less then. I don't have the figures in front of me but they were pretty reasonable in a 3 phase setup. They also didn't mention anything about a problem running on a generator when I talked to them and they know that is my plan at the moment.
Posted: Mar 25, 2008 04:46 PM	Hi John, To answer your question about our compressor, is wires for 3 phase. As to the gen govener, we have played with it extensively, as well as swaped it for a new one with the same results. It does not matter what adjustments we make, it still resutls with a huge spike whenever the compressor kicks in. We have been in contact with reps for our generator, air compressor, electricians and our spray foam parts dealer and we keep going around in circles. So if a capacitor does not work, we shall be switching to a new compressor.
Lane Hogstad Posted: Mar 25, 2008 04:58 PM	Does it so it when the compressor has no pressure or all the time?
Posted: Mar 27, 2008 09:29 AM	All the time, compressor void of pressure or not. Anybody have a good line on a new/used screw compressor? I see that most of the replies talk about eaton compressors, what is the norm for spray rigs down there (I'm in an igloo up here in Canada lol). Kohler? Ingersol Rand? any comments on these guys?
Circle-D Posted: Mar 27, 2008 03:03 PM	I shopped them all, Kohler, IR, Curtis. I found the best bang (cfm) for my buck at Eaton.The only drawback is a waiting time as they can't build them fast enough.
Michael Flander Posted: Mar 27, 2008 04:46 PM	I have some tidy 7d's in stock. They are made by US Air compressors. Digital controls, easy to use. 34 cfm, soft start, even maintenance alarms. Mike Flander 763-428-5075
John Shockney Posted: Apr 01, 2008 10:13 AM	Sorry I didn't grt back to you sooner. In my hvac experance 3ph motors don't need capasitors for start up due to their nature they have high starting torque. There are some systems that control the speed of a 3ph motor by changing the cycles of the power going to the motor through the use of electronics and capasitors. But, a cheep thing to try first is change the motor side pully to one size smaller, I know this would reduce air output but it might get you by. Or you could replace the motor with a larger one this would reduice starting and run amps due to more windings in the motor. Sorry I couldn't be more helpfull thanks John AIRPRO
Kevin Morse Posted: Apr 03, 2008 09:24 AM	Why not try our GCRS40-40 generator/compressor? Unit is 40 kw with an integral 40 cfm rotary screw air compressor slaved to the engine. No electrical requirement for the compressor. Please visit our website at www,morseindustrial.ca or email for more info at kmorse@morseindustrial.ca