On Mon, 22 Feb 1999 11:28:26 EST, Lftlesl@aol.com wrote:
>
>In a message dated 2/21/99 7:09:49 PM Central Standard Time,
jack@cocoinc.com
>writes:
>
><< It would reach atbout 50 psi
> then go hmmmmmmmmmm then it would trip the fuse. I tried a few
outlets all
> the same. Being a beautiful day and determined to work on the car
I rented
> one from Home Depot only to find it would not run at all, tripping
the fuse
> as soon as it started. Is this common with 110 compressors?,
what do most of
> you use? 110? 220? gas? >>
>Jack-
>I've had the same breaker-tripping problem with my 5HP
compressor (110 volts).
>I minimize it by unplugging everything else on the circuit -- we can
live
>without the toaster, microwave, etc. for a few hours . Also make
sure you plug
>the compressor directly into the socket -- don't use an extension
cord. With
>these precautions, I can get through an afternoon using the
compressor with
>only a couple of trips to the breaker box.
I'm kind of concerned about this. First off, your compressor should
indicate how many amps it will draw. Household 110v circuits
are either rated at 15 or 20 amps. (except maybe for some
special circuits like dryer if not 220v?) Obviously it would be better
to use a 20 amp circuit. Next, is the circuit protected by ground
-fault detection? These circuits are pretty sensitive to poor
grounding conditions.
I don't know if the NEC has any limits on branch circuit runs
for 20 amp circuits. I don't think an extension cord (if it is
big enough in wire gauge) is going to cause your problem, but,
while I don't have AC induction motor data handy, I imagine if
there is a voltage drop, your motor will draw more current
than the amount on the data plate. So you might put on a
voltmeter and see what you are getting at the end of the cord.
In commercial settings there limits on when you are allowed to
use outlets. A commercial site would probably have to hardwire
the compressor to a branch circuit.
Another problem may be that the motor starter is just "across
the line". When an AC motor starts, there is a tremendous
current draw until it starts to get up to speed (probably around
1800 rpm). I don't know if household circuit breakers are designed
to trip on instantaneous current, of if there is some slight delay.
scott s.
scott s.
.
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