Small Air Compressor - Initial Set-Up

[Wagtail]

I've recently bought a small replacement air compressor. I've assembled it according to the instructions yet it is not running up to a 'useable' psi. The power source required is a standard (Australian) 220V 50Hz.

My only thinking is that, perhaps, I need to leave it 'plugged in' (not running) to charge up the capacitor.

Am I on the right track?

 

[newbury]

Need more details, like model etc. but I've always just plugged them in and they ran. Also mine always came assembled.

 

[old and tired]

Check your manual again to see if you need to run a break in period... I had a cheap one which required leaving it on for a certain amount of it running (not sure what needed to be seated...)

 

[SPYDERLK]

I've recently bought a small replacement air compressor. I've assembled it according to the instructions [[[yet it is not running up to a 'useable' psi.]]] The power source required is a standard (Australian) 220V 50Hz.

My only thinking is that, perhaps, I need to leave it 'plugged in' (not running) to charge up the capacitor.

[Am I on the right track?]

[[[ What does this mean?]]]
[No.]

 

[masseyrider]

I've recently bought a small replacement air compressor. I've assembled it according to the instructions yet it is not running up to a 'useable' psi. The power source required is a standard (Australian) 220V 50Hz.

My only thinking is that, perhaps, I need to leave it 'plugged in' (not running) to charge up the capacitor.

Am I on the right track?

I've only ever purchased 3 new compressors.
The only assembly they ever needed was attaching things like wheels and handles etc.
The other was putting oil in the compressor.
Never a problem otherwise.
Ask the place where you bought it or call the 800 number of the manufacturer.

 

[Wagtail]

[[[ What does this mean?]]]
[No.]

OK, 'usable psi' means just that... it attempts to pressurise the tank, the psi on the gauge rises to, maybe, 10psi... which is an unusable amount for what I require.

And, yes, the assembly was was simply attaching the handle/wheels & such out of the box... my last compressor worked 'straight out of the box'.

The brand is from a local hardware store (A$100.00) and rated for 150psi.

I'll check the oil level. Ta for that.

As to the "No" answer to my "am I on the right track"? Why do you think I started this thread.

 

[KennyG]

Off the wall question - is the drain valve closed? I've forgotten to close mine before and couldn't figure out why the pressure wasn't coming up.

 

[Wagtail]

Off the wall question - is the drain valve closed? I've forgotten to close mine before and couldn't figure out why the pressure wasn't coming up.

Not off the wall at all! I always drain the tank after use and went out to ensure that the valve is shut. Perhaps it was sticking... we'll see.

I will get back to everyone once I get this thing going.

 

[LittleBill21]

10 psi? either valve is open, or safety valve is open, or compressor is shot

 

[WinterDeere]

You did a really poor job of explaining the problem, and I can't even imagine what you mean by charging a capacitor... on AC power.

Is it running indefinitely, and just never reaching the pressure that would cause it to turn off? If so, then it is one of a few things, in rough order of probability:

1. No outlet fitting connected, it's just open. Many compressors come without an outlet fitting, since there are so many standards, they let you buy and attach whatever you intend to use. Feel for leaking air at one of the ports downstream of regulator.

2. Open or leaking drain cock valve. Put hand around drain, and you'll hear and probably feel if this is leaking or open.

3. Open or leaking emergency pressure blow-off valve. Same thing, put your hand around it, you should hear and feel air rushing out.

4. Belt or coupling between motor and compressor is missing or derailed.

5. Compressor itself is defective. Is this a piston type, diaphragm type, etc? If piston type with oiled crankcase, did it come pre-filled with oil?

 

[Wagtail]

^^^
Well I'm sorry that I wasn't able to adequately explain what the problem was as I'm not familiar with air compressors. I realise that there are many different types of compressors; mine has no belt, is wheel portable... just a small 'shop' compressor. I know that there is a large capacitor as there is a bloody big warning label.

Anyway, an update: It looks to be working now.

I checked the tank drain valve, open & shut it a few times, then left it shut. <possible 'fault'.

I then plugged it in to a power outlet and let it sit for a couple of hours. <Just to ensure that the capacitor was fully charged.

I checked the oil level and it was good.

I've just now turned it on and it has fully charged the tank (152psi) and automatically shut off. I'll check if it holds that pressure in a couple of hours, followed by turning it off, discharging the tank and then recharge to ensure that all is well.

Thank you for the constructive suggestions.

 

[Midniteoyl]

Unless you have some sort of 'starting capacitor' I don't know of any that have a capacitor. That said, a normal capacitor would be charged before you moved your hand to the start switch. I think you found the real culprit in a sticky drain valve.

 

[Wagtail]

Unless you have some sort of 'starting capacitor' I don't know of any that have a capacitor. That said, a normal capacitor would be charged before you moved your hand to the start switch. I think you found the real culprit in a sticky drain valve.

I agree on the capacitor... but it didn't hurt to eliminate it as a fault. No harm/no foul.

The compressor did bleed down a wee bit (130psi) after leaving it for a couple of hours. Still, I was able to use it to inflate the front tyres on the Z-turn.

I drained the tank and put it away in its corner of the workshop.

Thanks again to all.

 

[WinterDeere]

Glad you have it working. Sounds like it’s was the drain?

Just to close the loop on the capacitor, most single-phase motors (including compressors) have a capacitor which is momentarily switched in to start the motor, and sometimes a second to correct motor power factor. But these capacitors charge and discharge literally 100 or 120 times per second, depending whether you’re in a 50 Hz or 60 Hz country.

The warning is there, because depending on the instantaneous voltage at the moment when it was disconnected from power, some voltage can remain on the capacitor for hours after disconnecting. But there is no long-term (beyond milliseconds) capacitor charging effect requiring you to leave it plugged in for any period of time. Things like that are only applicable to DC circuits.

<— electrical engineer