Electrical problems with a compressor

I am trying to hook up a compressor; it’s the puma one shown on this e-bay add:

http://cgi.ebay.com/12v-1-5-gal-air...ryZ11751QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I have it all hooked up and it runs great, for a few minutes, and them it blows the 30 amp inline fuss I put on the hot wire. I hooked it up by running a 10 gage wire from my battery to the compressor, with the fuss placed on this wire, then another 10 gage wire from the compressor to the ground screw used by the battery. Everything works fine for a few minutes and then the fuss blows. Am I doing something wrong, or does anyone have any ideas? I’ve gone through two packs of fusses trying to fix this problem and am out of ideas.

I don't think the compressors are intended to run a 100% duty cycle.. trying using a thermal breaker.. atleast you wont have to replace a fuse each time..

Steev said:

I don't think the compressors are intended to run a 100% duty cycle.. trying using a thermal breaker.. atleast you wont have to replace a fuse each time..

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Actually, they are rated for 100% duty cycle...
I am interested in finding out any other info that you may get on this subject, as I have one coming to me in the mail this coming week. Where did you mount it? You may need to run wire larger than 10 gauge if you have it mounted in the back of your jeep, due to the length of the wire. You may also want to use a larger fuse. This thing draws 30 amps, according to the spec sheet.

The wire coming off the compressor is 10 gauge, which is why I ran 10 gauge to it. I ran about 20 feet of wire, maby alittle less, would that make the fuse break?. I mounted it on the floor in the back, it's not the best mounting location in the world, but will do for now. If I can't get it to work with 10 gauge I will try a thicker wire, but that means re-running the wire, which is something I don't really want to do. besides I was hoping to use it tomorrow.

For the short periods I have been able to use it, its been working great. I aired one tire down to 10 PSI and then aired it back up to 28 PSI fairly quickly. Havn't been able to really time it however since one tire is about all I can do before the fuse breakes.

FiFo said:

The wire coming off the compressor is 10 gauge, which is why I ran 10 gauge to it. I ran about 20 feet of wire, maby alittle less, would that make the fuse break?. I mounted it on the floor in the back, it's not the best mounting location in the world, but will do for now. If I can't get it to work with 10 gauge I will try a thicker wire, but that means re-running the wire, which is something I don't really want to do. besides I was hoping to use it tomorrow.

For the short periods I have been able to use it, its been working great. I aired one tire down to 10 PSI and then aired it back up to 28 PSI fairly quickly. Havn't been able to really time it however since one tire is about all I can do before the fuse breakes.

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I'm not an electrician, but I do know that the smaller the wire, the more resistance and that resistance only increases with length. You mentioned that you were using 30 amp fuses. That is the amperage at which the fuse will blow, so since the compressor draws that much under normal use, you would be better off using a 35 or 40 amp fuse and larger gauge wire.

Does the wire get warm?

What pressure is the tank at when the fuse blows? It sounds like the pressure switch is set too high and the compressor is stalling against the load.

If the compressor really does draw up to 30-amps, that's why you're blowing 30-amp fuses. I certainly wouldn't recommend running a 40-amp fuse on 10-gauge wire either. I would also seriously consider running heavier wire as you're dropping 1.2 volts over that 20' of 10 guage. Here's a calculator that might help you out. http://www.powerstream.com/Wire_Size.htm

old_man said:

What pressure is the tank at when the fuse blows? It sounds like the pressure switch is set too high and the compressor is stalling against the load.

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X2Xvoltage drop.

I have 6 ga. to my compressor in the cargo area. The next time I tear into the interior, I'm going to switch it to 4 ga.

Well, i pulled out all of the 10 gauge wire that I was using. Am I reading the chart that is linked above correctly in that I need to run 6 gauge?

The compressor either blows the fuse once the PSI goes much above 100 PSI if you start it up from empty and just let it run. If you hook it to a tire and let it run so that the PSI never has a chance to build up it runs for a minute or two and then blows the fuse. I'm going to rewire it over the weekend with a lower gauge wire and see if that fixes it.

Oh, and the wire did not seem to get warm, cut the fuse sure did.

go with a thicker wire, make it as short as possible and run it to a higher amp fuse. resistance= voltage/amperage. if your voltage stays the same, and the resistance increases, then your amperage decreases which will make the heat go up and everything work harder to get the needed power to the compressor. also, 30 amps is probably an average so you should always go a little higher so as to compensate for the inconsistancies in life...
the rating of the fuse isnt how much it puts out all the time, the fuse is just a connection that, if over exerted, will "break" so that the circut is not connected. you can run a 50 amp fuse with a 30 amp appliance, it will just have 20 available amps that may run through it. may also lower the temp of your fuse...