Circuit Breaker Saver

I don't suppose a soft starter would work with a high starting load compressor, or would it?

Other than having your own battery and invertor to start the thing the only other way I can see at this time of the morning is to have your compressor driven by a internal combustion motor, same as a genset....

Are you sure the trips are tripping due to escess starting current and not because they are set to trip on a low earth leakage current? Which under heavy starting (impulse) loads could cause it to trip?

Just some thought ....... John **off to get another coffee**

No way to coordinate the tripping curve of an unknown breaker. Every one is different so even if you found a way to make it work one place, it may not work anywhere else. Besides, it all depends on the existing load at the new location. My suggestion would be to tell the homeowner that they must provide you with a 15A outlet on a circuit that has nothing else running on it. If they forget and the breaker trips, they get charged for the call anyway.

The only other option might be to replace your compressor motor with a 3 phase 230V unit, then buy a VFD that will convert 115V 1 phase to 230V 3 phase. This is a standard option for a number of VFD suppliers now. Even then, if they have 14 amps already running off of that circuit, this is not going to help.

GET AN ADAPTOR and run the compressor off your truck

1 HP = 746 watts. at 12 volts = 62 amps.

You can buy AC generators rated at 1500 watts for trucks that you mount under the hood and run with a pully.

and on to the next one

In a domestic application circuit breakers are not normally rated for use with electric motors and hence can't tolerate the high inrush currents at startup. To work correctly you really need to have a the correct type of circuit breaker installed.

I have seen this problem before and there was a work around of sorts. The way it works is to start the compressor up without a load on it then when it is up to speed connect the load. This is achieved with a diverting valve with one port connected to the load and the other vented to the atmosphere. When the compressor is started it vents the compressed air to the atmosphere then when the compressor is up to speed the compressor output is connected to the load. See diagram below.

The way to test if this will work is disconnect the compressor from the receiver/load then start it several times with it venting to the atmosphere. If the circuit breaker doesn't trip then this technique will work. It may however need a soft start option as well and if both don't work the only option is the correct circuit breaker.

If you only need a small amount of copressed air, how about the old trick used to inflate flat tyres!

Just remove a spark plug from your truck engine and attach a hose to that cylinder with a one way valve to your receiver, then start your engine and you will get a compressed air source...

Okay, so the compressed air is a bit dirty with fuel (even explosive!) and the engine is running unbalanced, but hey ho you can't have everything... and if it gets you out of a mess then its worth a try?

I agree with Electroman's ending comments. Modern homes in the U.S. require GFCI breakers on all outdoor receptacles, which will interpret a large inductive load (your 15 A. LRA motor) as a ground fault and trip. Older homes did not have this requirement. There are GFCI breakers that are made for motors, but they are relatively expensive for residential use, thus are only used in commerical/industrial situations. The open air flow circuit suggestion during motor startup will not help if the breaker is the GFCI breaker normally used on dwellings. I assume that you are using the compressor to run pneumatic nailers, thus would need 80-100 psi. A portable gas powered compressor is best at sites where our truck-mounted compressor is too far from the worksite. Assuming that that your vehicle can be located within reach of your hoses, an inverter (12 VDC to 120 VAC conversion) is your best bet. You might have to run your truck's engine during heavy inverter use to ensure that you won't be stuck at the jobsite with a dead battery. Or you can mount a deep-cycle marine battery in your truck bed, that can be charged by your truck engine, to run the inverter. The aux battery should be "electrically connected" to the vehicle's charging circuit through a battery disconnect. Depending upon your compressor usage, you might need to install a larger alternator/regulator in your truck. This will maintain the MTBF of the charging system, and allow for faster charging of the aux battery.

Hope my four cents is off value.

You do not say what happens in situations after you reset the breaker. Surely it keeps on tripping ??. What do you do then?? you might be able to get a soft-start switch - but I have no info on them.

But that might be unnecessary, first it is worth checking the air pressure in the tank when you start up. If the tank happens to be at full pressure (at the troublesome sites) that might explain the tripping problem

Most compressors do not like starting up when there is pressure in the cylinder. The pressurer makes it hard for the piston to move and that slows the motor down - and therefore draws a high current long enough to trip the breaker.

It depends on the make and type of compressor but if yours has start/stop control (ie, it stops when air is not used - and automatically starts when you use the air ) it should have an off-loader valve that dumps any air in the cylinder so that the compressor can start on no-load until up to speed - then the valve closes(opens) to start pumping air until the pressure builds up to maximum. Then it cuts out again to stop pumping air - either with the motor continuously running but off-load, or via a switch to stop the motor.

If this valve is stick/leaky you might find that is the reason for your random problem.
- If you have an 'economy' version you might find you do not have an off-loader at all. Only a safety valve to dump excess air. All very inefficient - but then you are not paying for the electricity. You must then make sure that the tank is 'empty' before you switch the compressor on.

If the problem is due to vagaries of your particular customers supply - as you said - with other loads plugged in (you would surely find the breaker keeps tripping out at the same address) it might help to run your compressor at the lowest pressure your tools will run at. Or you might have to get to get a slightly smaller compressor or if you need that much air, then a twin arrangement where you start one at a time.

I have used time delay relays in the past to solve this problem. Here's an article for more info.

http://www.edn.com/article/CA198898.html

good luck

IF YOU ARE USING THIS COMPRESSOR TO RUN AIR NAILERS IN YOUR BUSINESS, I HAD THE SAME PROBLEM. I WENT TO MORE THAN ONE SMALLER COMPRESSOR INSTEAD OF ONE BIG COMPRESSOR AND A MANIFOLD TO RUN ALL THE TOOLS. NO MORE TRIPPED BREAKERS, NO MORE WRESTLIN THE BIG COMPRESSOR AROUND, NO MORE HEADACHES. THE OILLESS SINGLE TANK OR PANCAKE COMPRESSORS MADE BY ALMOST ANYONE NOW A DAYS ARE LIGHT, LONG LIVED, EASY TO STORE AND WILL RUN A SINGLE NAILER WITH OUT A PROBLEM. I DONT KNOW HOW BIG A CREW YOU ARE RUNNING BUT I HAVE PLUGGED AS MANY AS THREE OF THESE COMPRESSORS INTO ONE 15 AMP OUTLET AND NEVER HAD A PROBLEM.

A compressor that pulls 15A at startup from 110V would need something like 140A at 12 volts to get going and while this is possible you will flatten the battery fairly quickly. If you can give more info like the expected duty cycle, run current etc it may be possible to work out if it really is practical.

From what you say however it seems that the compressor doesn't always trip a particular breaker every time. If this is the case and resetting the circuit breaker allows the compressor to start then its possible that trying to use some form of soft/unloaded start might work.

If you can clarify with as much detail as you can it may be possible to find a fix.

If you are going to have the need for compressed air on a daily basis, buy a pulley-driven compressor and mount it under your hood.

Some engines have an unused pulley attached to crankshaft, but if not, they are available after-market.

They look like an air-conditoning compressor and provide plenty of output.Your engine will have to idle when in use.

The compressor has an electrical clutch(12 Volt) that disengages it when the setpoint is reached, and re-engages it when the tank pressure drops.

If you would like to see one, visit your local tire dealer that offers road-repair service

for trucks and tractors.There field service trucks will have them mounted.

Here's a chappy, ($10.00?) Just mount an adjustable relief valve, preadjusted to your max required pressure, and install it on the air load line. The compressor motor will keep on running continuously. Your only problem is the whistling noise when the valve opens. it is the same way it has been done on a gasoline engine driven compressors.

A lot cheaper than running your truck engine, paying for soft starters or other fancy toys. And best of all, the customer is paying the bill!

Wangito

I had similar problem, solved it with two things:

1st - got a MUCH quieter belt-driven compressor, the motor runs more efficiently than my old 'bargain store' unit, and starts 'softer'

2nd - always make sure my tank is empty of pressure before turning it on.

I saw the three-way valve idea above and agree this would allow you to start at no pressure and 'save' the air already in a compressed state in your tank, for the price of a valve and some plumbing work. If you decide the cost may be worth it, just make sure the valve is rated for the pressure you're using.

Also, it is true that the BEST solution is to make yourself fully independent of your customer.

If this is how you make your living, rather than a side-job, look into a Honda OHV (4-cycle) motor belt-driven compressor - they're quiet, dependable, and put out the air. Look at colemanpowermate.com for an example - the "Contractor" series wheelbarrow type are awsome for what you describe. Write off the expense on your taxes.

I agree!! that's exactly what I said in my post....

Use a compressor that uses a internal combustion engine... SIMPLE!

I think a twofold solution is best:-

1. Keep the system that you have now, when it works just use it.

2. Add a motor driven compressor (diesel or petrol)as suggested for when the customer AC connection fails, sitting on your truck and just switch over when needed.

That way your costs of diesel or gasoline will be reduced and the noise generated also for most customers, when the AC line stays up....

My original reply waffled on about off-loaders etc. But these comments were to enable you to utilise your existing compressor without going to any great expense

The subsequent replies about starting with zero pressure all make sense - and I like the one about earth leakage. But if this was the case (or if as you guessed something else was plugged in as well) then surely you would keep tripping the breaker.

OK you say, if your customer is home. But what if not???.

And what happens if they stay out for a long time - and lose a freezer full of food. Do they blame you for overloading their circuit and try to sue you.

The cost and inconvenience of all this is part of the solution.

When I bought my compressor, I got the largest I could find which ran off 110 VAC. The first time I used it with an extension cord, I blew the breaker. Let me first assume that you are in the U.S. Most household outlets are 20 amp and use 12 gauge wire. Try and get an outlet which does not have alot of other garbage running on the same circuit. If you HAVE to use an extension cord, use 12 gauge for a short run (say 20 feet max). If you have to make a long run, bite the bullet and get a 10 gauge extension cord. I paid close to $100.00 for my 100 foot cord, but I was sure happy to hear the compressor start with this cord in the line. I don't know if this will cure all your problems, but it certainly helped with mine.