Air compressor help

Magmotor said:
IBall: would you show me where in Ohms Law that you multiply ohms x volts and end up with Amps???:wow2: Using Ohms Law (EIR)with your information of 6.25 ohms, 12v you come up with 1.92 amps....using (PIE) with 12v you come up with 240 WATTS!!!....In an A/C system the 6.25 is impedance, not Ohms. You can't mix A/C values with D/C values in the same formula. :shrug:
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Boy I did screw the pooch on THAT.

Well that's a whole different story isn't it?

So if I correct the formula it still nets 20A! Of course we have no idea if the motor is in line. I better double check my numbers next time!
:deadhorse:

Edit, so I should scroll down before responding, OP says the motor is marked 600W. That is 50A!
So 10g would be just OK for a short 5' run, or so. So now we are looking at a 100A fuse or breaker though. And a bigger relay! I'd still go bigger on the cables, a lot bigger.
 
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IBallEngineer said:
Boy I did screw the pooch on THAT.

Well that's a whole different story isn't it?

So if I correct the formula it still nets 20A! Of course we have no idea if the motor is in line. I better double check my numbers next time!
:deadhorse:

Edit, so I should scroll down before responding, OP says the motor is marked 600W. That is 50A!
So 10g would be just OK for a short 5' run, or so. So now we are looking at a 100A fuse or breaker though. And a bigger relay! I'd still go bigger on the cables, a lot bigger.
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There's is nothing on the motor. I said the cable is marked 10gauge 600w. Not the motor ! The issue there is no info on the actual compressor. But only info on the pressure switch. That's why I think 25amp is enough. Because that is what the pressure switch is rated. The pressure switch had to be rated properly to what the compressor is rated.

Did you see my pic above ? The one I drew ? I'm attaching alligator clips. I'm not hard wiring it!

20A is nothing. Viair are @ 40A. so this compressor is either 20A or 50A or 60A
 
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I think you guys are trying to do amperage calculations based on the pressure switch ratings. That doesn't work because you don't know what the motor load is. Maybe if you do you calculations based off of the motor horsepower. 1 HP is 746 watts. So at the peak hp, which is 1, the amp draw would be 746/12=62 amps. At the continuous horsepower of .75, the amp draw would be 47 amps. A 50 amp breaker would probably be okay and a 10 gauge wire probably won't burn up but it might get warm. If the wire is very long, it probably needs to be a larger gauge or use two 10 gauge wires in parallel.
 
kolelt said:
There's is nothing on the motor. I said the cable is marked 10gauge 600w. Not the motor ! The issue there is no info on the actual compressor. But only info on the pressure switch. That's why I think 25amp is enough. Because that is what the pressure switch is rated. The pressure switch had to be rated properly to what the compressor is rated.

Did you see my pic above ? The one I drew ? I'm attaching alligator clips. I'm not hard wiring it!
Click to expand...

The switch was rated for AC, not DC.

Well 10G is just too small for my comfort. If you run it to air up 4 tires that thing is going to get really hot. Even 6 feet will likely melt insulation eventually. If you were only going 2 feet it would still only be "ok", for me.

Let us know how it goes!
 
lol I'm just lost now. Why would they have 10gauge wire original. ( unless it was mounted close to the battery ?) I want to have cables long enough to attach it to battery and let the compressor sit on the ground.

I do not want to hard wire or or install solenoid. I want it as simple as possible.

Is there a way for me to read how much amps it's drawing ? Let's say I hook it up the battery and put a multi meter on it somewhere ??

Man this compressor is truly a beast then isn't it ?
 
kolelt said:
lol I'm just lost now. Why would they have 10gauge wire original. ( unless it was mounted close to the battery ?) I want to have cables long enough to attach it to battery and let the compressor sit on the ground.

I do not want to hard wire or or install solenoid. I want it as simple as possible.

Is there a way for me to read how much amps it's drawing ? Let's say I hook it up the battery and put a multi meter on it somewhere ??

Man this compressor is truly a beast then isn't it ?
Click to expand...

Not with a basic DMM. They max out at 10A--most of them. You can get a clamp meter like this:

https://www.amazon.com/Auto-ranging-Digital-Clamp-Meter/dp/B001VGND88

or wire in a 100A external shunt and then use your meter doing a little math. Or something like this would work and you could install it permanently. I would say that's a good idea if you are going to be running that beast. This is a pretty good price, considering a 100A shunt alone costs about that much.

https://www.amazon.com/bayite-6-5-100V-Display-Multimeter-Voltmeter/dp/B013PKYILS/ref=pd_cp_469_1?_encoding=UTF8&pd_rd_i=B013PKYILS&pd_rd_r=05YND1KT8Q9K8S2HD16T&pd_rd_w=aQHZK&pd_rd_wg=hzzTo&psc=1&refRID=05YND1KT8Q9K8S2HD16T:

...Or I guess you could just cannibalize a decent heavy duty pair of jumper cables, cut off the clamps on one end, and wire those directly to the compressor. You would have no fuse, no switch and probably no insurance. I'd keep a fire extinguisher nearby but if you're careful it would work. Don't say I told you to do it. Connect the positive first, and then connect the negative to the engine hanger, not to the battery post. Slightly safer.

In Brazil I saw crazy stuff like that all the time. Here's an AC hookup from a favela:

Gato.jpg
 
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I'm going to have to tap into the 10g wire. I took apart top part of the compressor. To see if I can possibly change the existing wires straight to thicker ones. And they sit behind all the electrical, below all the brushes ect.

I was also think of just rednecking a cable with inline fuse holder and start at 20amp and hook it up. See at which amp fuse it will stop burning the fuse
 
I think you guys are trying to do amperage calculations based on the pressure switch ratings. That doesn't work because you don't know what the motor load is. Maybe if you do you calculations based off of the motor horsepower. 1 HP is 746 watts. So at the peak hp, which is 1, the amp draw would be 746/12=62 amps. At the continuous horsepower of .75, the amp draw would be 47 amps. A 50 amp breaker would probably be okay and a 10 gauge wire probably won't burn up but it might get warm. If the wire is very long, it probably needs to be a larger gauge or use two 10 gauge wires in parallel.
 
kolelt said:
I'm going to have to tap into the 10g wire. I took apart top part of the compressor. To see if I can possibly change the existing wires straight to thicker ones. And they sit behind all the electrical, below all the brushes ect.

I was also think of just rednecking a cable with inline fuse holder and start at 20amp and hook it up. See at which amp fuse it will stop burning the fuse
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aside from the electrical part,

make sure you run an OPEN air chuck. you don't want it to hold back any air, or build any pressure.
 
pauldub said:
I think you guys are trying to do amperage calculations based on the pressure switch ratings. That doesn't work because you don't know what the motor load is. Maybe if you do you calculations based off of the motor horsepower. 1 HP is 746 watts. So at the peak hp, which is 1, the amp draw would be 746/12=62 amps. At the continuous horsepower of .75, the amp draw would be 47 amps. A 50 amp breaker would probably be okay and a 10 gauge wire probably won't burn up but it might get warm. If the wire is very long, it probably needs to be a larger gauge or use two 10 gauge wires in parallel.
Click to expand...

If you look above, that is exactly how I calculated the draw. But I would never run a 47 amp steady draw off a 50A circuit. 80% is kinda my limit.
 
TheDurk said:
If you look above, that is exactly how I calculated the draw. But I would never run a 47 amp steady draw off a 50A circuit. 80% is kinda my limit.
Click to expand...

Looks exactly like this

Puma DE07 12-Volt 3/4-HP 50Ah Oil-Less Continuous Duty Tankless Air Compressor

And comparing this specific compressor to this EXACT ONE
Portable 12 Volt Compressor | Truck n Tow.com

50amps or 60amps is what I need. This is a industrial compressor ! It's a beast. Very excited to use it. My friend even gave me the hose reel that was attached to it. I guess you can almost run air tools of it.
 
He used 20 foot 10gauge wirenwithout issues. Thanks Durk. I'm get 50amp breaker. Looks like people are really liking it. In future I can add the tank under the truck. Where the one spare goes.
 
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If it were me, I would run at least 4 gauge wire with a 80 amp fuse on it and call it a day. When you want to use the thing, put the fuse in it, when you're not using it, pull the fuse.

Done...

One other thing, how are you going to regulate the pressure in the tank? Won't this thing just keep running and build up pressure since there is no pressure switch? Or is there some kind of relief valve that will let the excess pressure escape?
 
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I appreciate the advice everyone has given me. I will be running 50amp. Which is like minimum. No reason to overkill it. According to TheDurk, the link he shared. Guys ran 50 amp breaker without issue. Starting amps are below 50amp. So ....

Another question. Is it safe to jump from 10g wire to like 8 or 6 gauge ? As in use a but connector ? Because like I said. I opened up the compressor to look inside. The original wires run below all the electrical stuff. And I can see few stuff are sprig loaded. So I'm not messing with it. In other words, impossible to change the original wires for thicker wires. And not to mention the thick wires wouldn't probably fit inside the motor. So there is a reason why they simply ran 10gauge.

So again, if I leave about 1 foot of 10gauge wire and add 6-10 foot of 8 or 6 gauge. Will that be ok?
 
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