Humidifier MCA / MOP

[jwparker]

Im trying to determine the correct MOP for a commerical humidifier. The unit is 51kW. If i go by my standard motor calculations by the tables in the CEC i get an MCA 77Amps and MOP 175Amps. Is a humidifer calculated differently than a regular motor?

 

[rbulsara]

Is 51 kW all motor? A humidifier may have more elements more than just a motor. It may also have multiple stages. You may want to use the manufacture's published data on conductor size and overcurrent protection.

Rafiq Bulsara

http://www.srengineersct.com

 

[jwparker]

Its rated as a 51kW humidifier. Im electrical not mechanical so I dont fully understand what makes it up. I believe there are coils motors etc which all make up the rating. I do not have OEM specs as its not been purchased yet.

 

[rbulsara]

Request the data from the mfr or the vendor. You have to get the right info to make the right decisions.

Rafiq Bulsara

http://www.srengineersct.com

 

[jwparker]

Shouldnt I/we be able to do engineering work in order to determine what is required? We dont call every manufacturer to determine transformer inrush current etc. Maybe for very specific but general calculations should be available. I'm aware of how to do this for air conditioners and other multi-motor configurations but Im somewhat confused when it comes to straight humidifiers.

 

[waross]

Well assume that the humidifier use a 50 kW motor and a 1 kW heater. Calculate your wire size and protection required.
Now assume that the motor is 1 kW and the heater coils are 50 kW. Calculate your wire size and protection required.
Compare the results.
Either RTFM or call the manufacturer.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[rbulsara]

jw:
We can only engineer what we know. Transformer are built to known standards and we know what is in it. A humidifier is not a standard equipment. What is a "straight" humidifier? Humidifiers consist of multiple components, (heaters and motors etc,) which varies by the type of humidifying technology (infra red, ultrasonic, steam, etc.)and manufacturers. Engineers are not magicians or mind readers. Learn to obtain the data you need to do your work.

Rafiq Bulsara

http://www.srengineersct.com

 

[jwparker]

wow, a simple 'no' would have been sufficient. Me asking the question meant I did not know the answer. I also said I knew basically nothing about humidifiers. I realize you can only engineer what we 'know' and I was asking if we 'knew' a method to do this.

rb: You're answers are very patronizing. The idea of being on this forum is to help people not attempt to give lectures. I wish I knew everything like you do so I wouldnt have to ask questions.

Im not sure where you work but in my position we rarely have all available information and its frequently completely unavailable. I was merely looking for a general rule, which aparently there is none, which is the answer I was looking for.

 

[rbulsara]

jw:
You are not getting the message. There are no rules for unknown quantities. You need to find out what is in the humidifier you are interested in or being specified. It is not knowing about everything, it is knowing where and how to find answers. You are not going about it the right way.

Rafiq Bulsara

http://www.srengineersct.com

 

[electricpete]

Time to move on imo. Sounds like Bill and Rafiq gave a good answer which the OP already acknowledged "I was merely looking for a general rule, which apparently there is none, which is the answer I was looking for."

=====================================
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[rbulsara]

Agreed, Pete.

Rafiq Bulsara

http://www.srengineersct.com

 

[jwparker]

Also Agreed. Regardless thanks for the answer.