Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 67 users online :: 5 registered, 1 hidden and 61 guests


Most users ever online was 218 on Wed Dec 07, 2016 6:58 pm

Registered users: Bing [Bot], Exabot [Bot], Google [Bot], grumpyoldman, Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

Fridge compressor + regular compressor

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
Sponsored 
  • Author
    Message

Fridge compressor + regular compressor

Unread postAuthor: pipeboyswe » Mon Jul 25, 2011 12:44 pm

Hi today i tested to plug in the regular shop compressor to my friggy and the results were amazing! Alot faster filling times! :D But before i did that i poured in some synthetic motoroil (10W-40) and when i did come to about 500psi the compressor sounded wrrarrrr and then did shut down, i plugged out the hose and some oil dripped out (Only 1-2 drops). After 10 sec i plugged it in again and it worked again but this time only to about 300psi and the same sound again.
Have this happend to any of you? I think it is the motoroil reacting with the orginal oil in the friggy that makes it sticky and make the piston to stop.
Should i try to tip the compressor over and hope that the oil will drain out and then pour in some oil made for compressors?
What do you guys think?
  • 0

Attachments
2stagecompressor!.jpg
Do not take this picture too serious, i made it in paint, pictures from google and 3mins to spare xD
Last edited by pipeboyswe on Mon Jul 25, 2011 1:12 pm, edited 1 time in total.
User avatar
pipeboyswe
Specialist
Specialist
 
Posts: 40
Joined: Tue Sep 01, 2009 8:52 am
Location: Sweden
Reputation: 0

Unread postAuthor: warhead052 » Mon Jul 25, 2011 5:45 pm

I think you are over working your fridge compressor. Try linking up 2 fridge compressors to each other, same way as you would a regular to the fridge, and turn them on at the same time.
  • 0


warhead052
Major General
Major General
 
Posts: 1769
Joined: Mon Mar 21, 2011 5:41 pm
Reputation: 0

Unread postAuthor: Technician1002 » Mon Jul 25, 2011 6:23 pm

In normal use depending on the refrigerant the compressor was designed for, simply keeping the pressures in normal operating ranges will go a long way. The sudden BRRRR is often the starting relay turning back on. It uses the run current to know when to turn off when the compressor comes up to speed.

If the compressor was an R134a type, set the air compressor pressure regulator to about 35 PSI and don't pump over 450 PSI. Too high an inlet pressure with a high discharge pressure will overload and stall the compressor. This can lead to the motor overheating and burning out. Pressure well above 450 PSI on the outlet can lead to valve failure or a blown head gasket.

If the compressor is an R22 model, it will have a lower displacement (pumps slower) but will be able to take a little higher pressure on the inlet and outlet. You really need to limit the inlet pressure on the R134a models as they were designed for lower inlet pressures. High pressure will overload them and let out the magic smoke.


In simple terms of the volume of air, when you pump 1 atm (0 PSI) of air it will pump slowly and you can reach fairly high pressure without stalling the motor. When you double the inlet pressure to two atm (14.7 psi) you are asking the motor to haul twice the material up to a high pressure. This almost doubles the load on the motor. Increasing to 3 atm (29.4 psi) again increased the load on the motor and increases the pumping rate. If you feed it about that pressure for an R134a compressor and output about 150 PSI, your have the compressor in the normal operating range. When you shove 8 atm (7 bar or ~100PSI into the inlet and expect an outlet pressure above 300 PSI, you have it fatally overloaded. It will overheat and go up in smoke if it runs long that way. If you are lucky, it will stall, kick in the start, then trip out due to too high of current.

You may have burnt the insulation on the motor winding on the first try so the windings are stating to burn out. This may be the reason for the lower pressure on the second run.

It does help to know what you are doing when you play with a fridge compressor so you don't burn it up early in the life.

If you have an AC Wattmeter such as the Kill-a-Watt, you can monitor the power used by the compressor to tell when it is up to full load. Full load amps is marked on most compressors. When you exceed full power current, it will be overheating. This overload is what kills many AC compressors in a heat wave. The inlet pressure is high due to a hot room, and the outlet pressure is way too high due to the hot outdoor temperature. Sagging voltage from an electrical overload increases the compressor current and hastens the burnout.

Full load Amps is listed on the compressor nameplate as FLA. The maximum start current is marked as LRA which stands for Locked Rotor Amps.

Kill-a-Watt meter

Image
  • 0

User avatar
Technician1002
Chief of Staff
Chief of Staff
 
Posts: 5190
Joined: Sat Apr 04, 2009 11:10 am
Reputation: 14

Unread postAuthor: Crna Legija » Tue Jul 26, 2011 1:37 am

yeah its amazing difference, buy my compressor got to 900psi and would have go more but i stopped it.

i bought a spray gun compressor it puts out 40psi and i have it hooked up permanently now, would it be safe to run both compressor from one power cord so one switch would turn them both on/off?
  • 0

'' To alcohol... The cause of, and solution to, all of life's problems.”
--Homer Simpson

Add me on ps3: wannafuk, 8/11/11 cant wait
User avatar
Crna Legija
Major General
Major General
 
Posts: 2333
Joined: Sun Jul 20, 2008 5:14 am
Location: australia
Reputation: 0

Unread postAuthor: Technician1002 » Tue Jul 26, 2011 1:45 am

On the power cord issue, the correct answer is "It depends"

What is the cord rated for? Is it a light duty cord or a large wire size monstor?

What is your total connected load? How much power does each compressor draw? Is it less than the current rating of the cord?
  • 0

User avatar
Technician1002
Chief of Staff
Chief of Staff
 
Posts: 5190
Joined: Sat Apr 04, 2009 11:10 am
Reputation: 14

Unread postAuthor: jhalek90 » Tue Jul 26, 2011 1:48 am

Crna, just plug the both into a power strip with a switch. That would work.
  • 0

jackssmirkingrevenge wrote:I wonder... if you put flammable vapours inside a lady... could you get her to diesel?

POLAND_SPUD wrote:Anything is possible with the proper 3-way valve.
User avatar
jhalek90
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 498
Joined: Fri Aug 14, 2009 5:37 pm
Reputation: 0

Unread postAuthor: Crna Legija » Tue Jul 26, 2011 3:31 am

jhalek90 wrote:Crna, just plug the both into a power strip with a switch. That would work.


ahahah yea double plug and use the wall switch.
  • 0

'' To alcohol... The cause of, and solution to, all of life's problems.”
--Homer Simpson

Add me on ps3: wannafuk, 8/11/11 cant wait
User avatar
Crna Legija
Major General
Major General
 
Posts: 2333
Joined: Sun Jul 20, 2008 5:14 am
Location: australia
Reputation: 0

Sponsored

Sponsor
 


Return to Pneumatic Cannon Discussion

Who is online

Registered users: Bing [Bot], Exabot [Bot], Google [Bot], grumpyoldman, Yahoo [Bot]

Reputation System ©'