I think Clare had the best idea about changing your single 115 line to a
220-240 line. Although I don't know if that calls for a third wire or
if you can use the ground as a neutral and drive a ground rod in at the
garage. If possible, that is your best bet for now and down the road.
Double your capacity through the same wires.
IF the circuit is dedicated to the compressor you can get away with
L1 and L2 and ground with no neutral as you do not need any 110 volt
capability. No ground rod issues ar anything, assuming you have a
grounded cable now. You do need to mark the white wire red, or pigtail
a red wire to it to identify the former neutral wire as a live
On 2/11/2011 12:25 PM, firstname.lastname@example.org wrote:
That doesn't sound so great anymore, power for the compressor but no 120
for everything else. I'd be checking to see if the wire can be pulled
or not through the old conduit. If so then install a legal/code/safe
run with 240 and a neutral. But if he just wants to inflate tires why
bother. On the other hand he mentions sandblasting, either a tiny
blaster, way too much patience, or go with the 240.
Oh my more setbacks. Trying to compare my 25+ year old 1hp Sears
compressor to the one in the link. My 1 horsepower puts out 5.8 SCFM @
90PSI. Yours is rated different, it puts out 5.2 CFM @ 90PSI. So we
need to convert SCFM to CFM or vise versa. I want to see how my old 1HP
compares to the new 2HP.
I can think of another. It possible that there is some design
difference in how the motor is wound or some other aspect that makes
it more difficult for it to stall if someone shuts it off and then
immediately back on when it's pumping under high pressure.
Far as I know they all unload when the motor stops I wouldn't bet on
starting against high head pressure.
I think the answer is closer to what clare wrote. In looking around, the
motors I saw on compressors were capacitor start, capacitor run. Those
motors, in general, have relatively high starting torque and relatively
low starting current for that torque. I have seen no reason to believe
"special compressor motors" are anything but standard cap start, cap run
The problem I have is Jon's 3HP SPL motor. It is a scam rating. Just
like the scam ratings that resulted in the class action lawsuit, which
the manufacturers settled. If Jon knew it was not a real number then why
post it? (And then there was Jon's 2.3HP miscalculated value.)
A scam "peak" 3HP motor has a peak (near stall) torque that is equal to
the normal running torque of a 3HP motor. It is not the starting torque
of a 3HP motor.
For many of its smaller compressors, Grainger gives both the scam "peak"
HP (competitive with Jon's scam rating) and a real HP.
I haven't seen any reason to believe that the "real" HP is not the
appropriate rating. Because there are plenty of scam ratings, you can't
compare compressors based on HP rating (as many people here have said).
Even with real HP ratings you need to compare the air you need with what
a compressor provides (also as many people here have said).
============This is similar to joule ratings on surge suppressors. In that case
there is not a defined way to measure the joule rating. So some
manufacturers use deceptive ratings. As a result, some major
manufacturers no longer give a joule rating.
On Mon, 07 Feb 2011 10:56:41 -0500, email@example.com wrote:
I asked about how to choose a reliable used compressor, not how to
select an appropriate one, but your comment is constructive, and
deserves a response.
I will be using the compressor for small construction and woodworking
projects. The tools I'll probably use most will be a utility stapler
and a finish nailer. I might do some painting, but that will so rare
that I wouldn't want to get a larger (costlier, heavier, more power
hungry) compressor to keep up with a paint gun.
Last time I owned a compressor it was a dual-tank Emglo. I think it
was rated at 1 1/2 HP and drew about 14 amps. I'll be perfectly happy
to get something similar now, although I'd prefer one that's less
noisy. I understand that the lubricated models make less noise.
You can get some good deals at pawn shops. Buy a brand name, and buy one
that looks clean, that's about all I can suggest. If you're just going to
use it for nailers, etc, you don't need much, and as long as it will build
up pressure, and doesn't leak, there isn't much else. Take a bottle of
Windex, and pressure it up, and test for leaks. Open up the bleeder valve
on the bottom once it's pressured up, and see if any water comes out. If it
does, pass. It means the owner hasn't bled it regularly, and there will be
water and rust inside the tank.
Heart surgery pending?
Read up and prepare.
Learn how to care for a friend.
Download the book.
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