Hi
We have motorized valve which operates on 24 V DC when receives command on its IO's.
Its IO's includes 1AI command /1AO/2 DI (close feedback and open feedbacks)
this MOV operates slowly. Its duty cycle is 80 %. .
Does it means that 80 % ON time & 20 % off time.
in which category this duty cycle falls such as S1, S2,....
Any limits on time cycle.
please guide.

thanks in advance

 

The motor can be running 80% of the time. It can run 48 minutes in an hour. If it runs more than its rated duty cycle then the motor tends to over heat.

 

The motor can be running 80% of the time. It can run 48 minutes in an hour. If it runs more than its rated duty cycle then the motor tends to over heat.

hi david,
80 % duty stands in comparison with hourly basis. or 10 minutes basis. is there specific standard for this.
Does this motor falls in duty cycle category such as
S1: continuous duty
S2: short time duty
S3-S8: periodic

 

Good luck answering your question.

I'm told IEC 60034 covers motor duty cycles, but I don't have a copy.

When I dealt with 90/160° actuators (typically on valves, occasionally on a damper) I could not find a factory guy to explain which "S" class category their smaller torque (HVAC) motors operated under.
The larger torque models were spec'd as being rated for 100% duty cycle, but smaller torque actuators were clearly capable of only intermittent duty. When put in applications where the valve was "hunting", constantly stopping and reversing, the motors failed in a short period. The real problem was PID tuning, but the motor took the blame.

I found a summary of the different duty classes "S" classes here, "Understanding Motor Duty Rating:
https://myelectrical.com/notes/entryid/106/understanding-motor-duty-rating

I remember seeing a statement about the S3 class using a 10 minute interval in 3.3.2 of "Duties of Induction Motors, Chapter 3" from "Electrical Power Engineering Reference & Applications handbook".
https://www.electricalengineering-book.com/pdf/chapter-865728.pdf

But how broadly does that apply, if it even does, to actuators? I'm in the dark, too.

 

Er, ..., Um, ..., Why not ask the motorized valve manufacturer?

I've worked internationally, and I've never understood the attitude that everyone is trying to cheat everyone else and no one is to be trusted. EVER.

And, I don't think I will ever understand it.

Even when I was working in Asia and the Middle East, when I contacted manufacturer's representatives or even the manufacturers themselves I was always pleasantly impressed and was able to get my question(s) answered or help with my issue. A couple of manufacturers even sent technicians to site on two different occasions to help sort the problem(s).

A good manufacturer's representative or manufacturer wants to sell equipment. And they want people to be happy with their equipment--so they can sell more. (Good) Word of mouth is the best advertising in the world. And people remember good service--but not as well as they remember bad service. All you can do is ask--and if they won't oblige, then look elsewhere. Because there is always someone who's looking to help and sell equipment.

Now, that being said, there are unscrupulous people in the world--but, in the business world they don't survive long in the dog-eat-dog world. They might think they are fooling people, but, again: Word gets around. Good words travel slower than bad words.

I guarantee it.

THIS is a question for the manufacturer, or the person who specified this valve for the application. And it's quite often harder, if not downright impossible, to get the latter to respond. A good manufacturer's representative or manufacturer can help determine if the valve is the right one for the application.

Try it. Odds are, you'll probably like it.

 

One would hope that the factory would provide information, but Honeywell had no one who could or would answer actuator questions. If it wasn't printed in the spec sheet or manual, you were on your own.

Back 15 years ago, Beck could not provide a wiring diagram without the serial number from the unit in question, and wouldn't even answer which terminals the power connected to over the phone. I couldn't believe that wiring was that serial-numbered specific within a group or class of actuators.. Couldn't get the serial number until I was on-site and then had to wait a day for a reply. Just plain silly.

 

Sai09
Google "Motor Duty Cycle" and you will find quite a number listed. IEC Standards list more than 20. Others even provide varied shape formulae related to stop-start patterns!
Regards, Phil Corso

 

Good luck answering your question.

I'm told IEC 60034 covers motor duty cycles, but I don't have a copy.

When I dealt with 90/160° actuators (typically on valves, occasionally on a damper) I could not find a factory guy to explain which "S" class category their smaller torque (HVAC) motors operated under.
The larger torque models were spec'd as being rated for 100% duty cycle, but smaller torque actuators were clearly capable of only intermittent duty. When put in applications where the valve was "hunting", constantly stopping and reversing, the motors failed in a short period. The real problem was PID tuning, but the motor took the blame.

I found a summary of the different duty classes "S" classes here, "Understanding Motor Duty Rating:
https://myelectrical.com/notes/entryid/106/understanding-motor-duty-rating

I remember seeing a statement about the S3 class using a 10 minute interval in 3.3.2 of "Duties of Induction Motors, Chapter 3" from "Electrical Power Engineering Reference & Applications handbook".
https://www.electricalengineering-book.com/pdf/chapter-865728.pdf

But how broadly does that apply, if it even does, to actuators? I'm in the dark, too.

Hi david,
thanks for your words. i really appreciate you.
I'll get back to you once i get the answer.
thanks

 

Er, ..., Um, ..., Why not ask the motorized valve manufacturer?

I've worked internationally, and I've never understood the attitude that everyone is trying to cheat everyone else and no one is to be trusted. EVER.

And, I don't think I will ever understand it.

Even when I was working in Asia and the Middle East, when I contacted manufacturer's representatives or even the manufacturers themselves I was always pleasantly impressed and was able to get my question(s) answered or help with my issue. A couple of manufacturers even sent technicians to site on two different occasions to help sort the problem(s).

A good manufacturer's representative or manufacturer wants to sell equipment. And they want people to be happy with their equipment--so they can sell more. (Good) Word of mouth is the best advertising in the world. And people remember good service--but not as well as they remember bad service. All you can do is ask--and if they won't oblige, then look elsewhere. Because there is always someone who's looking to help and sell equipment.

Now, that being said, there are unscrupulous people in the world--but, in the business world they don't survive long in the dog-eat-dog world. They might think they are fooling people, but, again: Word gets around. Good words travel slower than bad words.

I guarantee it.

THIS is a question for the manufacturer, or the person who specified this valve for the application. And it's quite often harder, if not downright impossible, to get the latter to respond. A good manufacturer's representative or manufacturer can help determine if the valve is the right one for the application.

Try it. Odds are, you'll probably like it.

Thanks for your reply.

 

Sai09
Google "Motor Duty Cycle" and you will find quite a number listed. IEC Standards list more than 20. Others even provide varied shape formulae related to stop-start patterns!
Regards, Phil Corso

yeah.. vast information is available over web.
but its applicability to our content always matters.