precipitator cable

[bjeservice]

hi
i need to know why is the precipitator cable cross section area used in cement factory = 70 sq.mm although its average dc current < 1 amp. Also i need to know why it is generally be Copper and not Aluminum cable.
any information or link will be appreciated

 

[jtkirb]

Not sure of WHICH cable you are talking about, but I would guess the diameter is for mechanical reasons.

Chances are CU is less reactive than AL in that application. Which cable are you talking about?

JTK

 

[cuky2000]

Oversizing cable is often done for voltage drop reasons. Also the use of copper vs. aluminum most of the time is a matter of preference.

The group of user that prefer aluminum are typically utility with trained workmanship that purchase large quantities of cable saving significant amount of money since aluminum is cheaper than copper.

On the other hand, most user justify the selection of copper at higher cost are typically residential contractors with relative small wiring sizes and does that purchase cable in relative small quantities or concern with long term maintenance. Copper fans claim this conductor has higher quality image, better connectability and superior mechanical properties.

 

[itsmoked]

bjeservice; If you are truly talking precipitator then electric fields are the working medium and hence wire diameter could be very important.

 

[bjeservice]

Dear Friends
thankyou for replay ,but
the electrostatic precipitator working voltage is 70 KV DC,
taking from hv transformer & rectifier.The normal dc current is 0.5 Amps . Cable length is about 60 meter. So for the voltage drop reason of that huge cable size of 70 sq.mm Copper is not satisfied.
May be the reason of electric fields of the impedance of line are important as the precipitator depends on corona discharge methode to do its work.
PLEASE if one know why that cable area and why copper respond me. thanks all again

 

[itsmoked]

The electric field around a surface is a function of the shape, specifically the radius, of the surface. The smaller the radius the higher the field potential,[E = k Q / r2]. If the field potential exceeds the breakdown potential of the air then you will get corona.

As you've stated, the current being carried is waaaaaaay below the abilities of the cable. The only solution that might work would be to use tubing that has the same OD.

 

[jtkirb]

The cables were designed that way for a reason- mechanical, electrical, or both. In the case of a precip, I would suspect AL wire would not last very long in a corrosive environment.

Why not ask the precip mfg?

JTK

 

[waross]

I concur with itsmoked and jtkirb. Corona and corrosion.

 

[bjeservice]

But corona and corrosion occur inside the precipitator not around the cable that transmit hv current from transformer to precipitator

 

[cuky2000]

I am agreeing with you under these conditions that voltage drop may not be an issue. On the other hand, still is a mystery for me the reason of oversize the cable. Could you please verify the following:

- Cable manufacturer
- precipitator working voltage: 70 KV DC
- Is the cable rated for KVac or 70 kVdc?
- What kind of insulation? (EPR, XLPE, Paper, Oil, etc)
- How 0.5 dc current was measured?
Please verify that the HV cable length is 60 meter. I presume that the rectifier is at the same distance + or -

 

[bjeservice]

If you search the web under item "precipitator cable" you will see the detailed specification of the cable.

1. i donot know the manufacturer but there are Copper and Aluminum cables used in electrostatic precipitator , and i donot know what the drawback of Al. cable.
2. working voltage 70 kv dc.
3. cable rating about 110 kv dc
4. the insulator XLPE
5. in precipitator there is control panel guages of current , and voltage

One should know that the electrostatic precipitator depends on Corona Discharege in order to charge the cement particales and then pull it to the opposite voltage electrode inside the precipitator. So keep in mund there are continous disharge inside it

 

[jtkirb]

BJS-

Did you ever ASK the precip mfg? A lot of higher voltage cables are sometimes only able to buy at a minimum size. It doesn't pay to make something larger than a #2AWG wire at that voltage.

You have never been specific about what you are really looking for and why. Any info helps.

JTK

 

[bjeservice]

jtkirb
I do ask a precipitator cable mfg but till now i got no answer
this size of cable must has relation with electrostaic preci. , it has no meaning to understand cable size & current alone.
if i get the answe i will respond