Simple compensated, variable heating control

[velyx]

Hi guys,

I've got the following question:

[FONT=&quot]On a simple compensated, variable heating control, what temperature measurements are required?[/FONT]

I hope to receive the answer.

Thank you in advance to all of you!

 

[Marvo]

Can you give a website link to the actual control you're asking about? I'm not a heating engineer and I'm not sure what a 'simple compensated variable heating control actually is, ies this a fancy thermostat or some kind of PID controller?

 

[velyx]

Unfortunatelly no. This question is from one electrical test from the agency HillMcGlinn. I tried to find some answer in the internet, but without success.

 

[Marvo]

Well it's a term I'm not familiar with but breaking it down into its elements; a variable heating control is basically a thermostat. Compensated is the tricky bit. Do you know if it's referring to domestic house heating or whether it refers to industrial process heating?

 

[velyx]

I reckon that it should be refer to industrial process heating. I think so, because of profile of the agency Hill McGlynn, which I see now is merged with Randstad Construction, Property & Engineering. I wrote the question in the same manner, as it appeared on the test. All the test was electrical with 11 questions. According recruitment consultant it is very simple test. If it is so simple why I couldn't find the answer through the inernet? This test was conducted before about 2 years.

 

[Marvo]

You need to know the application so you can figure out exactly what's being compensated for. The question asks what temperature measurements....plural. Usually with a heating process you measure the temp of the object being heated. The other measurements must be related to the compensation being applied but without more info it's still anybodys guess.

 

[velyx]

Thank you for your answers! Obviously this is a tricky question. As I told you earlier, it is one among the another 11 questions and I have no additional information about what is the application or what they want to be compensated for. After your answer I arrive to a conclusion that this question is put improper from the agency.

 

[Marvo]

Maybe there's a clue in the previous or following questions or possibly a general theme to the questions....if there isn't I'm afraid I'm stumped. Maybe another member will come along with some inspiration. Good luck.

 

[velyx]

These 11 questions are different, because the porpose is to comprise more different areas. The theme is only this: electrical test. I have rendered difficult with the following question as well (from the same test): [FONT=&quot]What is a difference between a non-essential and essential rising busbar system?[/FONT]
[FONT=&quot]What these abbreviations stand for: [/FONT][FONT=&quot]TR&N, [/FONT][FONT=&quot]SD&N?[/FONT]

 

[johnboy6083]

usually essential and non essential supplies are there to keep essential service live, in the event of mains failure.
In a power station i was working on recently, the essential supplies were for things like, emergency lighting (also had batteries, to cater for the few secs before generator kicked in), motorised valves (also had UPS for same reason as last), chemical showers and switchgear(400kv).
Non essential supplies wre for things like power sockets, non emergency lighting, street lighting, rollershutter doors.


so when the power fails, the backup generator kicks in, but takes a few secs to power up to full load. In the meantime anything that is safety critical is kept going by UPS, either in the form of localised batteries (Em lighting) or a central battery room (motorised valves).

The reason they dont have everything on a generator is because of cost. by reducing theload on the genset, it saves on the initial costofthe genny, and the cost of the extra cabling and switchgear required.

 

[velyx]

Thank you very much for your answer, but the question is: What is a difference between a non-essential and essential rising busbar system?
It is good and very useful for me to know about the supply - essential and non essential, but I need from stringent definition to this specific question - what is the essential and non essential RISING busbar system hence difference between them.
Thank you in advance to everybody for cooperation!

 

[johnboy6083]

A rising busbar system is primarily used in tall buildings. Instead of running armoureds up the building to supply the different floors, a busbar system is used instead. This is usually in the form of busbar trunking, which is trunking with busbar inside, supported on insulating material. Every so often, flexible connections must be used to compensate for expansion, as busbar can accommodate higher temperatures than cable. To account for the skin effect, sometimes parallel bars are used, rather than use larger conductors. To take the power from the bars, a tap off box is used, this will usually incorporate some form of protection, ie mccb or fuses. Hope this helps mate, any more questions, I will try and help.

 

[velyx]

Thank you!
About the following abbreviations: TR&N, SD&N. Do you know what they mean?

 

[Marvo]

Never heard of either abbreviations TR&N or SD&N. I even searched through my database of electrical codes and regulations and drew a blank These aren't general electrical abbreviations, they must be very specific to a particular field of piece of apparatus.

 

[thepurple1]

Normally your compensated heating circuit or V.T circuit feeds radiators, the temperature is compensated from outside air temperature. The settings we normally put in are at 1 degrees C OAT gives a flow of 70 degrees C around the V.T and at 20 degrees C OAT gives a 20 degrees C V.T flow. The temperature is controlled on flow not return