Hospital Sterilizer Question

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bcorbin

Senior Member
I'm trying to get power to a large, freestanding sterilizer unit.

The sterilizer literature says:

The sterilizer requires a CBA phase rotation. The correct phase rotation must be present at installation.

I am curious about a couple of things. What exactly is the reason for this reverse wiring config? Aside from that...why don't they just wire the cord and plug, or do it it inside the machine? It seems very odd to provide a receptacle that can't ever be used for any other piece of equipment if you don't need to.

If anyone can shed some light on this, it would be very much appreciated.
 

Buck Parrish

Senior Member
Location
NC & IN
I not sure I understand you.
I am guessing the manufacturer does not want it to turn the wrong way at start up. It may damage the equipment.
 

qcroanoke

Sometimes I don't know if I'm the boxer or the bag
Location
Roanoke, VA.
Occupation
Engineering
I'm trying to get power to a large, freestanding sterilizer unit.

The sterilizer literature says:

The sterilizer requires a CBA phase rotation. The correct phase rotation must be present at installation.

I am curious about a couple of things. What exactly is the reason for this reverse wiring config? Aside from that...why don't they just wire the cord and plug, or do it it inside the machine? It seems very odd to provide a receptacle that can't ever be used for any other piece of equipment if you don't need to.

If anyone can shed some light on this, it would be very much appreciated.

I've never seen instructions that told me to wire it out of phase rotation. Seen plenty that told me to make sure it was in A,B,C rotation though.
I would do as the instructions directed making sure it is out of rotation with a rotation meter.
Otherwise, if the smoke escapes you may own a hospital grade sterilizer.
 

dmagyar

Senior Member
Location
Rocklin, Ca.
Rotation meter

Rotation meter

Sounds like at a minimum you'd need to reference a rotation meter. The "CBA" is somewhat arbritary depending on things like the primary source and connections.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
I'd want to make sure I can see a rotating part and know which way I should see it rotating.
 

nakulak

Senior Member
the rotation isn't arbitrary. rotation is rotation. take c, hook to 1st lead on rotation meter. then take b to 2nd, then a to 3rd. get proper rotation or not on the meter. sure, that's the same as bac and acb, but it's not arbitrary, it's the direction of rotation. (relative to what c, b, and a or l1,l2,l3 leads are on the piece of equipment.) (unless they haven't identified the leads on the equipment, in which case I agree it's arbitrary.)
 

bcorbin

Senior Member
I understand that it needs to be the opposite of the rest of the building.

What I don't understand is why. What exactly about a sterilizer requires this?

It seems to me the phase order reversal should be accomplished inside the machine, and not at the receptacle.
 

mivey

Senior Member
the rotation isn't arbitrary. rotation is rotation. take c, hook to 1st lead on rotation meter. then take b to 2nd, then a to 3rd. get proper rotation or not on the meter. sure, that's the same as bac and acb, but it's not arbitrary, it's the direction of rotation. (relative to what c, b, and a or l1,l2,l3 leads are on the piece of equipment.) (unless they haven't identified the leads on the equipment, in which case I agree it's arbitrary.)
nicely put.
 

John120/240

Senior Member
Location
Olathe, Kansas
phase rotation

phase rotation

Help me understand please; Why specify "CBA" phase rotation
before we know what rotation "ABC" would produce ?
If the rotation is not correct just change any two connections ,right?
Thank You
 

mivey

Senior Member
Help me understand please; Why specify "CBA" phase rotation
before we know what rotation "ABC" would produce ?
If the rotation is not correct just change any two connections ,right?
Thank You
Maybe it is like nakulak said in post #7: the CBA labels are on their terminals/connections. That would be the best situation because that will make your life so much easier.

Swapping two leads will reverse the rotation.
 

Jraef

Moderator
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Probably made by American Sterilizer in New Jersey. In older autoclaves they used an odd custom made multi-port steam valve that directs steam in and out of the jacket and chambers based on timing controls from the control panel. They used small 3 phase gear motors to turn the valve rotor and rotation is critical. If they turn the wrong way, even for a moment, you might damage the teflon seals in the ports and they cost probably about $10,000 to replace by now (I used to work on them in the early 80s, they were $5,000 then!). It's also really difficult to see the rotation as well during setup; the moving parts of the valve are buried inside the case of the unit, up above the door. While it's true that phase rotation is relative, their statement is more akin to "C.Y.A." in case the valve gets damaged. Get a rotation checker so you can CYA too.

That issue was so much of a pain in the rear that the company I worked for made a tidy little business of rebuilding their machines and getting rid of that valve by using MOVs (Motor Operated Vales, not Metal Oxide Varistors). Normally you can't use MOVs on steam because they can't take the heat; the motors fry. But what we did was mount them to a manifold frame made of stainless steel square tubing, then ran the cold water supply through the tubing to keep the valves cool. Worked great, although now I would imagine someone has noticed how much cold water was wasted. Still, probably cost them less in the long run...
 

ron

Senior Member
Instead of thinking about it as CBA, just be sure it is counter clockwise rotation. The building might be that already, you never know.
I design for a building that has (2) utility sources, one clockwise and the other .... well you know.
 

bcorbin

Senior Member
Okay...if they need reverse rotation, why don't they just design the machine with the motor turned around 180? Or just take the standard ABC wires from the power cord and switch them at the motor terminals inside the machine?

What exactly is accomplished by changing the phase rotation at the receptacle, other than making it a PITA to make sure it gets done right? It seems to me this is just shoving the responsibility for it working right from the product designers to the electrician.
 

Crionics

Member
I understand that it needs to be the opposite of the rest of the building.

What I don't understand is why. What exactly about a sterilizer requires this?

It seems to me the phase order reversal should be accomplished inside the machine, and not at the receptacle.

Not exactly a correct statement. Some utilities provide ABC, others CBA...Some plants don't even know what they have until they try to bump a motor. Also, the phase rotation really has no meaning unless referenced from the Utility. I've gotten in to the habit of using 123 nomenclature because of this.
 

Crionics

Member
Okay...if they need reverse rotation, why don't they just design the machine with the motor turned around 180? Or just take the standard ABC wires from the power cord and switch them at the motor terminals inside the machine?

What exactly is accomplished by changing the phase rotation at the receptacle, other than making it a PITA to make sure it gets done right? It seems to me this is just shoving the responsibility for it working right from the product designers to the electrician.
How do they know what rotation you have at your facility?
 

nakulak

Senior Member
they are specifying the rotation order, and that's all you need to check. As someone else said, it doesn't matter what phase is what, but it matters that the rotation direction is correct.
I use my rotation meter once in a blue moon, but it's there when I need it just for wacky units like this.
 
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