×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

"COS" feature on electric actuators. What is meaning?

"COS" feature on electric actuators. What is meaning?

"COS" feature on electric actuators. What is meaning?

(OP)
Hello:
I use electric actuators for motorized valves and dampers in power plants applications.

In some catalogues of electric actuators, I have seen a column entitled "COS" and has some values, usually from 0.6 -0.9.

I can't found what is the mechanical meaning of this feature, and how it's related with the quality or benefits of an electric actuator.

I will really apreciate comments. Thanks in advance.

RE: "COS" feature on electric actuators. What is meaning?

It is related to the electric performance rather than the mechanical. COS is the abbreviation of cosine.
It refers to the Power Factor (PF) of the electric consumption.
PF= cos phi
If cos phi = 0.6, it means PF= 0.60

RE: "COS" feature on electric actuators. What is meaning?

(OP)
Thanks aolalde for your answer, now specs. has more sense.

RE: "COS" feature on electric actuators. What is meaning?

That would be power factor AT FULL LOAD.  At lesser loads the pf will be lower.

RE: "COS" feature on electric actuators. What is meaning?

One of the search pages shows a cosine relation to the centerline of the actuator to that of the disc(i.e driver and driven) and the resultant force transmission. Did you speak to the manufacturer?

RE: "COS" feature on electric actuators. What is meaning?

I would tend to agree more with quark...I doubt that it could be a power factor..

just a hunch..ask the mfr as quark recommended..

RE: "COS" feature on electric actuators. What is meaning?

Calfersoporte:

Could you post all the data displayed for the referred electric actuator?
It will be wise to analyze it considering what Quark is trying to mean.

RE: "COS" feature on electric actuators. What is meaning?

"in some catalogues of electric actuators, I have seen a column entitled "COS" and has some values, usually from 0.6 -0.9."

Which catalogs and which actuators?

RE: "COS" feature on electric actuators. What is meaning?

(OP)
Thanks to aolade, rbulsara, quark.

Next I include some specs. as apears on Catalogue:

S4 service - D.R. : 30%
Nominal type torque (lb-ft): 44
Output speed (RPM): 11
Time/turn (sec/turn): 5.42
Power(Kw): 0.1
Sped (RPM): 750
Current rated A: 2.5
Current start A: 3.0
COS:  0.95
Eficiency: 18%

This is an example of information that appears on specs.

Thanks everybody again for all you valuable comments.





RE: "COS" feature on electric actuators. What is meaning?

To me, COS is related to the parameters of the electric actuator.

RE: "COS" feature on electric actuators. What is meaning?

(OP)
BJC:
Thanks for your interest on my reply.

Catalogues are for LIMITORQUE L120 Series (appears power factor in place of COS), BIFFI F01 series (same as Limitorque), ROTORK Series AQ (same as Limitorque), L.Bernard(COS in place of power factor)

With the help of all repliers (thanks aolalde,DickDV,quark,rbulsara), now specs. of manufacturers are clear and I can to choose best option on specific actuators.

RE: "COS" feature on electric actuators. What is meaning?

It looks like power factor.  What is the language where the valves are installed.?
I would guess Limatorque sold the valves somewhere where english is not the native language.  They want the nameplates in whatever so they hire a translator to rewirte nameplates and manuals.  The translator looks up "Power factor" sees Cosine and put COS in place.  

RE: "COS" feature on electric actuators. What is meaning?

(OP)
BJC:
Language is english, and valves are installed in México. Limitorque is prefered brand here. Thanks for your comments.

RE: "COS" feature on electric actuators. What is meaning?

Calfersoporte.
Have you tried writing Limatorque?
http://www.limitorque.com/products/l120/apps.asp
They use to have good customer service.  They are supposed to be keeping record on all those valves in the Nuke plants. I know a lot of those were changed out.
It was always scary checking out so,ething like an SMB4.  I use to use an electrican at the valve, one at the MCC and one at the control panel when I tested them. All of them ready to throw a switch, breaker or clutch at a moments notice.   If the limits weren't set the operator could drive the stem right thought the bottom of a valve.
Laguna Verde had a few Limatorques if I remember right, but there was some German made (Auma I think) and some Hatachis which were Limatorques made under license.

RE: "COS" feature on electric actuators. What is meaning?

(OP)
BJC:
Thanks for valuable comments.
I will write Limitorque in order to improve technical literature that I had.

RE: "COS" feature on electric actuators. What is meaning?

Maybe the COS is there to indicate the apparent power that will be consumed.  The kVA will be the kW/PF.  From this the actual current use can be calculated.  The kW is only the useful work performed.  The kVA is the actual power required.  Could be a marketing ploy?  

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources