Tip & How-To about Air Tools & Compressors

Air compressor will not start

An electric air compressor motor may start up fine on an empty tank but not when the tank has air in it. Additional torque and power is required to start when not empty. The electric wires may be too small or their length too long and represent electric resistance in the circuit. Larger gage wire will have less resistance and provide more power at motor start up under load.
A motor uses 6 times the amps when starting, a normall size and length wire is capable to deliver this power momentarily. The problem is when the wire is lengthened without using a larger gage wire. Resistance consumes power and the wire resistance will consume power causing a voltage drop to the motor. A motor, as most electric loads needs plus or minus 10% of its rated voltage to operate. What I'm saying is that a larger gage wire must be used, 1 gauge size to 25 feet, 2 gage sizes to 50 feet, or more size larger when using extension chords depending on length. I keep some romex of heavy gage with chord ends on it to use as temporaty long extension chord for compressor or welder use.

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2 Answers

Will an electric motor with more horsepower and more rpm hurt a compressor pump?


Electric motors seem to turn around 1125 rpm or 3600 rpm. The pulley size on the motor and pump must be adjusted to achieve the desired result without overheating /loading the motor. I have seen pumps turning from 800 to 1200 rpm using different pulley size on motor, motor hp and motor rpm. Some brands will turn same pump from 1200 to 3600 rpm depending on if was electric or gas motor. This will certainly shorten the life of the pump but will most likely work. Most turn an average of 1200 rpm for good balance of long life and good supply of air. Pump rpm is usually limited to the power of the motor. Cost effective match of 1.5 hp motor will turn pump about 1000 - 1200 rpm for about 5cfm. Rol Air 2hp motor turns 2 cyl pump about 1100 rpm for 10 cfm. Good luck

Mar 17, 2015 | Campbell Hausfeld Tank Air Compressor, 1...

1 Answer

Ingersall-Rand T 30 Model 2340 Motor overload trips when trying to fill air tank. How long should it take to fill the tank with air with tank empty. If tank is full it may cycle one time when using air.


You need to know the size of the tank before you can figure pump up time from empty to full. It sounds like you have a bad tank check valve. A bad check valve typically causes the motor overload to trip when starting.

May 21, 2010 | Ingersoll Rand 2340/2475 Electric Air...

1 Answer

air compressor struggles to start but eventually starts


If the proplem only happens after the initial start-up with the tank empty, then your back flow valve is sticking and preventing the compressor from kicking over imediately. If it does it all the time, even when the tanik is empty, then your capacitor on the motor is not charging correctly.

Jan 17, 2010 | Craftsman 3 gal. Air Compressor, 1.5 hp,...

1 Answer

Motor startup trouble while pressure in tank


My first thought was that the check valve is allowing pressure back into the compressor and preventing the motor from turning. That's still my best guess right now.

I think the cold weather start symptom is what you would see with any engine/motor -- it requires more torque to get it going. In this scenario, if the check valve weren't leaking, it would start okay when cold.

May 06, 2009 | Clarke Power Products Inc AC2001 2HP 4...

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