3 Phase compressor?
hva...@pop.mpls.uswest.net
When changing out a 3 phase compressor, how can you be certain the new
one turns the right way? Keeping the wiring straight will be easy this
time, but suppose you come onto a job after someone else tears out? Will
it run, would the pressures be goofy, will it give that one huge death
rattle, then sieze???
--
HVACMAN
"Some people are worried about the difference
between right and wrong. I'm worried about
the difference between wrong and fun."
P.J. O'Rourke
AUSTIN1880
>When changing out a 3 phase compressor, how can you be certain the new
>one turns the right way?
Doesn't matter does it ? Unless it is a scroll I would not be concerned about
rotation.
Ted Morgen
hva...@pop.mpls.uswest.net wrote in article
<3595A8AC...@pop.mpls.uswest.net>...
> When changing out a 3 phase compressor, how can you be certain the new
> time, but suppose you come onto a job after someone else tears out? Will
> it run, would the pressures be goofy, will it give that one huge death
> rattle, then sieze???
>
> --
> HVACMAN
>
> "Some people are worried about the difference
> between right and wrong. I'm worried about
> the difference between wrong and fun."
> P.J. O'Rourke
>
noted
that some of them will have better oil pressures running one way from the
other.
Maybe our more learned compressors folks here can expound on this?
Regards,
Ted
paul milligan
"Ted Morgen" <tmo...@evergreen.net> pondered briefly, and wrote:
>Hermetically sealed compressors will run in either direction.
Ummm..... no. _recips_ will. Scrolls will not ( whether
hermetic or not ).
Sonofdawra
>When changing out a 3 phase compressor, how can you be certain the new
>one turns the right way? Keeping the wiring straight will be easy this
>time, but suppose you come onto a job after someone else tears out? Will
>it run, would the pressures be goofy, will it give that one huge death
>rattle, then sieze???
>
>--
>HVACMAN
>
reciprocating. All others require proper rotation. Noise level and pressure
readings should immeditately indicate wron rotation on scrolls and rotarys.
Word of warning from Copeland seminar [you guys at Copeland should be proud of
me for rememebering this since its been several years]: on some of their
semihermetic 3 phase recips, there is a slip plate that alligns ports between
the compressor body and the external oil pump. If the compressor has run
several years in one direction, this slip plate can wear in and will not move
properly to realign ports for reverse rotation. This will cause the compressor
to go off on oil pressure safety. Therefore, if you have a Copeland
semihermetic that suddenly has oil pressure problems after something like an
electrical service changeout, now you have an idea to try. Reverse the motor
and see if oil pressure is fine.
Neil H.
hva...@pop.mpls.uswest.net wrote:
>
> When changing out a 3 phase compressor, how can you be certain the new
> one turns the right way? Keeping the wiring straight will be easy this
> time, but suppose you come onto a job after someone else tears out? Will
> it run, would the pressures be goofy, will it give that one huge death
> rattle, then sieze???
If you are talking about replacing a reciprocating compressor it
shouldn't matter which direction the motor runs. If you are working on a
previously run compressor, take caution -- although the recip will run
in either direction, I've heard that the oil pump on many recips will
not work if the compressor rotation direction is changed.
If you are talking about scroll compressors, use your gauge set -- the
scrolls only pump in one direction, so if the beast isn't pumping at
start-up, it's probably running backwards. As long as you don't
maintain reverse rotation for a long time, you shouldn't hurt the
compressor. I'm still leery of allowing a scroll to run backwards
(because of motor failure problems), but the compressor manufacturers
seem to be doing a good job of "hardening" the compressors against this
type of failure. In your case, you shouldn't need to run the compressor
for more than a minute, so no damage should be done.
If you are talking about screw compressors, reverse rotation may indeed
turn the compressor into scrap.
Neil H.
--
My Email address is Spamouflaged.
Please remove "Spamnot." from my Email address when replying.
R. Bartlett
I've never seen a hermetic thats had an oil pressure tapping-which one are
you refering to?
cheers
richard
Donnelly Refrigeration
On Sat, 27 Jun 1998 21:21:32 -0500, hva...@pop.mpls.uswest.net wrote:
:>When changing out a 3 phase compressor, how can you be certain the new
:>one turns the right way? Keeping the wiring straight will be easy this
:>time, but suppose you come onto a job after someone else tears out? Will
:>it run, would the pressures be goofy, will it give that one huge death
:>rattle, then sieze???
I have managed to get three pase coplamatics to run that were locked up just
by switching to wires.
Still running after about two years.
Donnelly Refrigeration
Somewhere in the USA
red...@YYYearthlink.net
Remove YYY for email reply
hva...@pop.mpls.uswest.net
It's a scroll... Thanks everyone for the thoughtful responses...
catfish
In that case you can't miss it when they are run backwards they sound like
parts will be coming out of the can.
<hva...@pop.mpls.uswest.net> wrote in message
3596C9C0...@pop.mpls.uswest.net...
turtle
this is turtle.
i don't have all the 50 cent words to speak with but this is what you look
for.
scroll or recipicating or what ever . i don't care. if compressor sound
like a 500 pound rattle snake coming from the condenser unit---- cut power
off --- don't wait to see gauges --- cut power off. reverse any two leeds
coming to unit, or any two leeds to compressor. turn unit back on and see if
rattle snake takes off again. this is the way to go at it and don't worry
about who what or ever the type compressor it is. i don't have to think at
all when firing up a 3 phase condenser.
email me and i can cover some cases that the way they have acted before in
the past.
i don't study them , i install them.
TURTLE
hva...@pop.mpls.uswest.net wrote in message
<3595A8AC...@pop.mpls.uswest.net>...
|When changing out a 3 phase compressor, how can you be certain the new
|one turns the right way? Keeping the wiring straight will be easy this
|time, but suppose you come onto a job after someone else tears out? Will
|it run, would the pressures be goofy, will it give that one huge death
|rattle, then sieze???
|
paul milligan
"turtle" <tur...@worldnetla.net> pondered briefly, and wrote:
>scroll or recipicating or what ever . i don't care. if compressor sound
>like a 500 pound rattle snake coming from the condenser unit---- cut power
>off --- don't wait to see gauges --- cut power off. reverse any two leeds
>coming to unit, or any two leeds to compressor. turn unit back on and see if
>rattle snake takes off again. this is the way to go at it and don't worry
>about who what or ever the type compressor it is. i don't have to think at
>all when firing up a 3 phase condenser.
Sorry, you're totally wrong, no matter how glad you are that
you don't have to think.
If it's a scroll or a screw ( or a centri ) , it *DOES* matter
which way it turns, you *MUST* get it right, and you *DO* have to
think, and you *DON'T* 'just reverse any two leads' without knowing
whether or not it was phased correctly to begin with.
Your simplistic approach works for recip and only recips !
HVAC The Critter
Unless it's a scroll, it will run either way. No GOOFY pressures.
Scrolls will let you know if they are running backwards, no pumping
and they scream!
Semi's will run either way as well, although the oil pump sometimes
will give better pressures at a specific rotation.
Finally, the wiring diagram will show you the phases if
it is critical.
turtle
this is turtle.
yes you are right , now this is the simpleton view but, used at first , to
be used as to not mess up anything. i deal with recept. and scroll only , on
air conditioning. i don't get to see many screw type [ is screw type the
thing of future]
on recept. reverse leeds now i have burnt up 2 tranes 10 ton scroll's years
ago , when they came out with scroll on them. they said to remove power and
remove leed off compressor and then return line and power and unit will be
fine . it work . i ask them if they want me to turn around 3 times after
taking leed off , they say no just do this. simple old me done this on the
new scroll compressors and it work. at that time i devised the rattle snake
sound method. i don't understand it but just work on them. let me know of
this.
paul milligan wrote in message <3597645f...@news.mindspring.com>...
Jabarco
(snip)
>if you have a Copeland
>semihermetic that suddenly has oil pressure problems after something like an
>electrical service changeout, now you have an idea to try. Reverse the motor
>and see if oil pressure is fine.
......then, run out to a Copeland parts distributor and get a new oil pump come
back and install it.
Enthusiastically,
Jabarco, HVACR/PTST
Polleke
It does not matter really if not stated on the compressor.
However if it is an old one that always running clockwise please put
it back on clockwise again.
any diesel motor can run in both directions only the injection needs
retiming.
A few compressors will just not turn and take high amps. Reverse
direction and it will be ok.
Oil is other story. If changed direction it is possible to have other
pressure it depends on the layout of the pump.
On Sat, 27 Jun 1998 21:21:32 -0500, hva...@pop.mpls.uswest.net wrote:
|When changing out a 3 phase compressor, how can you be certain the
new
|one turns the right way? Keeping the wiring straight will be easy
this
|time, but suppose you come onto a job after someone else tears out?
Will
|it run, would the pressures be goofy, will it give that one huge
death
|rattle, then sieze???
|
|--
|HVACMAN
|
|"Some people are worried about the difference
|between right and wrong. I'm worried about
|the difference between wrong and fun."
| P.J. O'Rourke
|
|
Paul Deelen
shooter (at) xs4all (dot) nl
Specialised in trouble shooting.
refrigeration and ships are my main fields.
One man problem solving company.
tel/fax +31736139136
JAMES FINUCANE
only beconcerned if it is a compressor other than a recipe., if it is
invest in a phase direction meter