Air compressor advice needed

[Norm in Fujino]

While in the states recently assembling building materials for a container load to Japan, I spotted this Harbor Freight Model 95386 Air Compressor on sale for $99.99. I knew I was taking a chance, but I picked one up and threw it in the container. The container arrived day before yesterday, so yesterday I opened up the compressor and tried it out. Since Japan has 100V current, I of course hooked up through a 15A 100v->120V transformer--the same one I normally use for the BT3000.

I followed the break-in instructions (yes, of course, I had oil in it), and I was intending to run the compressor for 30 minutes as the manual said, but it ran for only about 5 minutes, then I noticed the motor sound change slightly (it sounded like it was running slightly faster but threadier), and then the transformer popped its built-in circuit breaker and turned off.

This kind of activity continued thereafter: 5-6 minutes of operation, then the transformer breaker would pop. This happened even tho I was on a dedicated circuit, no extension cord, and had the air valve wide open. When I tried closing the air valve to compress the tank, the compressor would run till I got about 50 psi in the tank,then the motor would start laboring, slow down, and the transformer breaker would pop again.

I thought the problem might be the aging transformer, so today, I went into Tokyo and visited the transformer shop at Akihabara where I bought my previous one. The guy there suggested I get an industrial use 20A model (sold "naked" without box or plugs or breaker, just terminals), so I got it and brought it home. We have 20A breakers on all the circuits of our house, so I figured if the compressor was drawing enough current to damage the transformer, it would pop the house breaker first.

Well, the performance seemed marginally better, so long as I didn't try to actually compress air in the tank. When I closed the air valve to compress air, it got to about 70 psi before the motor began laboring, slowing down, then abruptly stopping with a "humming" sound (the new transformer doesn't have a built-in breaker). Interestingly, it didn't pop our 20A house breaker, so I assume the compressor motor is drawing >15A but <20A. I quickly turned off the machine, of course, but the performance was the same thereafter. The motor labors as air is compressed, eventually just stalls.

I know this isn't the forum for electric motor advice, and since I'm using the thing on a transformer in a foreign country, all bets are off, anyway, but has anybody a clue what the problem might be? Did I just get a DOA lemon?

I will try the compressor and new transformer on a couple of different house circuits tomorrow, and as a last resort (just to eliminate the circuits as a possible problem), I will wire an "extension cord" with romex directly to the circuit panel and hook the compressor to it as a test, but if things don't get better fast, I'll just have to buy a compressor here, and chalk my $100 loss up to Harbor Freight experience.

TIA for any advice.

[master53yoda]

Is the transformer getting hot, if it is it isn't big enough for the load.

In order to elliminate a transformer problem I would connect it direct into the the house through a #12 extension cord, it should run on the 100v system as they can typically go to about 96 Volts. I twill need to be on a 20 amp circuit.

If your power there is 50 Hz instead of 60 that will make a speed difference on a induction motor that the universal motor in the BT3000 and your other hand tools won't have a problem with. Do you have any other induction motor tools that you are using.

The transformers are probably buck and boost transformers and do not serve high induction loads well. unless they are very heavy.

That compressor is really about a true 1 hp compressor. Most compressors are now rated at peak HP instead of normal Hp.

let us know how it comes out.

[Norm in Fujino]

Is the transformer getting hot, if it is it isn't big enough for the load.

The transformer itself wasn't hot, but the connections got hot once when I tried running it on an extension cord (and it wouldn't even start, to boot).

In order to elliminate a transformer problem I would connect it direct into the the house through a #12 extension cord, it should run on the 100v system as they can typically go to about 96 Volts. I twill need to be on a 20 amp circuit.

I've tried it on two transformers, a 15A and 20A, and I also tried it on direct Japan 100V current (wouldn't even turn over). I think I've eliminated the transformer as an issue, especially since I bought a new 20A trans today.

If your power there is 50 Hz instead of 60 that will make a speed difference on a induction motor that the universal motor in the BT3000 and your other hand tools won't have a problem with. Do you have any other induction motor tools that you are using.

Only our refrigerator, and it runs well on a standard transformer.

What gets me is this: the specs say the startup draw is 15.5A, and running draw is 7.4A. I could understand its not wanting to start on my old 15A transformer, but once it gets up and is running, why can't it continue, if it's only drawing 7.4A? And is it supposed to bog down like this as the air pressure increases in the tank?

[WayneJ]

When I worked for Harbor Freight we had a high return rate on those compressor, both the 95386 and the 40400 (both the same comp) Yor probably got a bad one. Make sure that the termal breaker on the side of the comp isn't tripping out. It could have a bad breaker.
Wayne

[master53yoda]

what is the power frequency

If it is 50 Hz it may not be getting the speed high enough to keep the start circuit Centrifugal switch open. Which will bog down the motor, over heat and shut off on internal safety. If it is realy close to the speed it opens at, as the compressor comes up to pressure and slows down just enough to re-energizer the start switch. If this is happening it will in time blow the start capacitor and then it will not start no matter what. I have seen this issue on motors connected to a generator that is to small.

the refrigerator has a current relay on the start circuit so the 50hz wouldn't cause the same problem.

[dbhost]

I have this compressor, and I could have sworn I read all the way through the owners manual. I do NOT recall seeing anything in my manual about any break in period. And I have used mine for about a year now... I hope I didn't mess it up...

[Norm in Fujino]

I have this compressor, and I could have sworn I read all the way through the owners manual. I do NOT recall seeing anything in my manual about any break in period. And I have used mine for about a year now... I hope I didn't mess it up...

The manuals change over time; the paper manual I got was quite a bit different from the online manual, which you can download HERE. The online manual's section on breaking in the compressor has the following:

Initial run of the Air Compressor
5. Break in the new Air Compressor as follows:
a. Check the oil level (See Checking the Oil).
b. Make sure the Power Button is OFF and the unit is unplugged. Insert a male coupler (sold separately) into the female Quick Coupler and fully open all regulators and valves.
c. Plug in the Power Cord.
d. Turn the Power Switch ON.
e. Let the unit run for 30 minutes. Air will expel freely through the Coupler.
f. Turn the Power Button OFF.
g. Unplug the Power Cord and remove the male coupler

[dbhost]

Mine is the 40400, and my paper manual, I just re-checked, didn't say a word about any break in procedure. It was rather adamant about making sure that it was NOT run without oil though. (I am guessing they have problems with customers not filling them with oil prior to running them...)

Should I be worried I didn't do the break in?

[Norm in Fujino]

what is the power frequency

If it is 50 Hz it may not be getting the speed high enough to keep the start circuit Centrifugal switch open. Which will bog down the motor, over heat and shut off on internal safety. If it is realy close to the speed it opens at, as the compressor comes up to pressure and slows down just enough to re-energizer the start switch. If this is happening it will in time blow the start capacitor and then it will not start no matter what. I have seen this issue on motors connected to a generator that is to small.

Well, I know nothing about motors, so this lemon is soon to be SEP (Somebody Else's Problem). I'll donate it to the first motor whiz who wants it. Then again, maybe I should save it for the extra tank. If I decide my next compressor is too small, I could gain some extra tank capacity that way.

[Norm in Fujino]

Followup on the compressor.
Sure enough, the compressor is for 60Hz only, not 50/60Hz as you often see, so it may well be related to that difference (eastern Japan has 50Hz current).
At any rate, I didn't have time or knowledge to fool with it, so I immediately ordered a different compressor here in Japan. Made by PUMA in Taiwan, it has the same basic performance specs as the HF model, but it's got better construction, substantially quieter motor, and is several pounds heavier. It also cost 3x as much, but that's part of the joy of living in Japan . At the same time, it worked right out of the box, so I can't complain about that.

An acquaintance in town is going to take a look at the HF compressor this afternoon. I'll give it to him if he wants it. Otherwise, I'll try to find a home for it somewhere in western Japan, since they use 60Hz current there.