I have a Sears air compressor that is 240 and uses a different plug.
It's a PITA because I have to add a new (240) outlet to every house I
move to. Can I simply convert the motor to 110? How difficult is this?
Or do I need to buy a new compressor?
If the motor is dual voltage, which it will say on the name plate, you can
convert it. However whatever the amperage draw is at 240 volts will be
double at 120 volts, which pretty much means you'll need to run a dedicated
<dan> wrote in message
You must move very often.......
With that said, why dont you just take the outlet with you when you
move? It's not all that hard to add a dual breaker, piece of wire and
an outlet in a box, assuming this is in an open garage. Surely not
worth buying another compressor if that one works. Besides, 240
motors are much more efficient. From experience, I found that many
120v compr... wont start in cold weather, while a 240v one will.
Tell us the (real) horsepower of the motor or how many amperes it draws
at 240 vac and lots of guys here will be able to give you a more
My guess is that unless you imported a small compressor from somewhere
where 220 or 240 is the standard "household voltage" it's probably got
such a large motor that you'd be hard pressed to run it off a 120 volt
20 ampere circuit.
I said (real) in my first paragraph because more often than not the
advertised horsepower of air compressors and vacuum cleaners is
exagerated hype. They use some stupid "peak horsepower" measurement of
the energy the motor puts out when they apply a load which is large
enough to cause it to stall.
Agree. Some motors are dual voltage and you can alter the
connnections. But motor will take at least twice the current on 120.
Also the starting curent of a 2 HP motor, for example will/may be much
higher than when 'running'.
My neighbour modified his dual voltage bench saw motor from 240 to
But encountered a) A lot of voltage drop on 120 volts and b) The
circuit breaker would sometimes trip.
Had to suggest to him that he install a a 240 outlet and convert back
to 120 volts.
You move that much?!
Some 240v motors can be changed; others can't.
Normally they will give amperage for both 240 and 120v if they can.
There are exceptions; my 2hp dust collector says it is 240v only, but I
opened it up and found the conversion was simple. I called the manufacturer
about it. They recommend 240v only because 120v will lead to excessive
So, if it doesn't show it as being 120/240, check the 240 amperage. If it
is 9a or more you probably wouldn't want to run it on 120v even if you
could. If under, it might be worth digging further.
(I did convert the DC to 120v, putting it on a 10 gauge multiwire circuit;
so excessive voltage drop)
Maybe he can't, because......
"It's time to change partners again!"
Which is a line from the song "Alma" by Tom Lehrer:
Check the motor nameplate to see if it can be run on 110.
I had a fella give me a old Sears (Simpson, Sears, and Roebuck, as
a matter of fact) compressor mounted on a green horizontal tank,
he said it just made a funny humming noise. It had a black motor
on it, 240 only - not a dual voltage motor. Sure did hum funny on
110. I happened to have a dual voltage motor. I prefer them on
110 because so many places I work don't have 220 handy.
Keep the whole world singing . . . .
If this is bigger that 1HP you won't be using 120v.
Why not put a dryer plug on it. Everywhere has a dryer receptacle.
You can generally use a breaker 2.5 times the FLA of the motor per
430.52 if it is internal overload protection.
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