Compressor build questions

[Daddyoneleg]

Hello,i'm trying to put a compressor together and have a few questions.First of all this is what I have so far... The head is an IR 242-5n,the tank is an Eagle 80gal upright. I have purchased a Baldor L1410TM 1725 rpm single phase motor. I am trying to keep costs inline and need help with a Mag starter and a pressure switch. I don't know where to start.I don't want to spend the same on a starter as I did on the motor. The pump is a two stage 175 psi. Max rpm is 1040 and I have it sheaved to turn at 917 because @ 1040 the motor was drawing 25 plus amps @175psi on a test spin.I borrowed an amp meter from a friend. What starter and pressure switch should I use? Any help would be awesome. Thx.

 

[zkling]

Hi, Welcome to GJ Sounds like you are building up a nice compressor.

A 5hp motor or a REAL one like you have is really at the very top end for a pressure switch. It really should have a mag starter that is triggered by the pressure switch on the low side but the actual motor current is thrown through the mag switch.

Surplus center has quite a few cheaper pressure switches, if you are just using it to trigger a mag starter you can get away with a lower current unit. Since you have a 2 stage compressor, you need something in the ~120-175psi on/off range pressure switch.

As for an economical mag starter, ebay would probably be a good bet for a big name unit like Square D, Allen Bradly, Seimens. Voltage and current rated for your motor.

 

[Daddyoneleg]

Thx zkling, Just wondering if the on/off should be on the pressure switch or on the Mag or both. The motor is rated for 23 amps and has a manual overload reset and it did not trip when I was pulling 25 plus amps. Apparently that's where the service factor of the motor comes in. At 1.15 sf it won't trip or overheat.I have learned you can run into the SF but be prepared to shorten the long term overall life of the motor.Man it was movin' good air,from 120psi to 175 in 2min exact.I want everything to last so I changed from 1040 to 917 rpm.All being said, where would a guy set the Mag overload amps at ? Lots to learn... Thx

 

[Daddyoneleg]

I ordered a WEG 20-32 Amp adjustable motor starter with a reset only.I will have the on/off on the pressure switch. I did find out that CONDOR makes pressure switches with contactor built in and you don't need a mag starter it will handle a 5hp max setup.I see Quincy compressor uses CONDOR on some of their 5hp models. Now to find a pressure switch.... One really intresting fact I found out that Craftsman's best Pro 2-stage 80gal comp has a head hour rating of 1500hours[IF THE DUTY CYCLE IS OBEYED} and QUINCY COMPRESSOR has an hour rating of 50,000 + hours with a 100% duty cycle. Man you sure get what you pay for !!!! -Cheers