3ph flex

[FarmerJon79]

I want to replace some flex in my grainstore that feeds several grain augers. Supply is 3ph, the largest motor is rated at 4kW, longest run will be about 5 meters.

What size flex should I use?

What quality (Arctic?) of flex should I use?

Thanks

 

[Spark123]

What size and type of flex is there at the moment? Artic flex doesn't have much mechanical protection on its own so without seeing the environment where it is to be installed it is difficult to advise.

 

[industryspark]

What about posting some photo's of the location and the machines, might help recommend a suitable cable. Possibility that SY cable might be good for what your after but as already stated, that depends on the environment.

 

[ColJack]

given that this is a grain store, shouldn't it be explosion proof stuff....?

why do you need "flex"?

surely if it's a fixed piece of equipment then it should be wired in armoured or metal adaptaflex?

 

[FarmerJon79]

The augers in question need to be moveable, and work when they are moved, to help clearing blockages. The motors obviously vibrate as well, so flex is the only answer.

The flex is a mixture of some black rubber, some black PVC (I think) and some white (PVC?). The rubber cables are badly perished, hence the need to replace.

The environment is very dusty but dry, plugs are these: http://www.tlc-direct.co.uk/Products/LDPD930slash4P.html The flex will not touch the floor, so does not need to be abrasion resistant.

Will try to get some pics today.

Thanks

 

[Spark123]

Very dusty and dry can lead to an explosion!
Is there any way of contacting the people who make the augers to see if they have a direct replacement?

 

[FarmerJon79]

As far as I know these would have been supplied without flex, so the manufacturer would not be any help.

 

[Fuseblower]

I would be tempted to use SY cable and these glands...

http://www.csedistributors.co.uk/cable/cable-glands/a2f-cable-gland.htm

Regards
FB

 

[industryspark]

You probably should be assessing the risk of explosion as a first matter.......im not experienced in this kind of environment so cant offer much advice to be honest.

I have however been involved in some panel and machine building that are spec'd for explosive proof area, and SY flex and the correct explosive rated glands were used extensivelly. Sounds like an ideal cable to use in the situation you have to me.

 

[RF Lighting]

I don't do explosion proof stuff either, but we tend to use CXT glands for SY cable at work.

 

[industryspark]

Have used the CXT glands myself and also other more normal glands can be used to secure the SY (as with armoured cables its important to earth the braiding so this must be done). Remember doing some CXT style glands which had a horrible putty/resin that you had to mix and use in the base of the gland as part of the expolsion proof standard, awefull things to work with

 

[ban-all-sheds]

Very dusty and dry can lead to an explosion!

Boom!

 

[conny]

Are the motors 'Explosion proof'? This can be determined by looking at the nameplate and seeing if it contains the letters Ex, (the capital E will actually look like a reversed 3). It will also have something along the lines of dd, ee etc and possibly a zone number or Cat number. Is the motor frame aluminium or cast iron. There are other things to look for but read the following first and let me know what you find.
A complete description of the nameplate of any of the motors will be very useful before I can give you further advice but for now;
When were the motors installed and who installed them? You should have certificates to say that they are explosion proof motors and if they have been serviced in the past they will have to have been done by someone qualified to carry out such repairs. Laws regarding motors and explosive areas, be they gas, liquid, powder or any combination are very strict and a full service history must be maintained at all times and even follow the equipment to a new owner if sold/transfered or even just repaired/overhauled.
I'm sorry if I sound alarmist but I work in the electric motor trade and know this is not a job you should even contemplate yourself. You have to be qualified so seek profesional advice before you go any further please.

 

[Click-Sure]

Valid point about the motor, you may well need to think about the rest of the electicity distribution in the vicinity of the grain store.

I'll hopefully see my mate (a sparky down't pit) who knows about the explosion side of things and see if he has any ideas as regards your cable and glands.

Are you a member of the NFU, they may well have a department that can advise.

 

[conny]

FarmerJon,
I have spoken to my team leader today who is just about to sit his exam to be able to instruct others in the repair and maintenance of flameproof motors and equipment. He agrees that a grain store is a potential explosion area and any electrical equipment should be appropriate for the environment it is used in. In other words if you are using 'bog-standard' equipment in a grain store then you are quite literally 'playing with fire!'

Check the nameplate on your motors and see if they contain ANY of the following letters or symbols.

Ex, (the E will look like a reverse 3), EEx d, EEx de, EEx e, EEx p or any combination such as, EEx pe, etc.

If you see any of these then the motors are flameproof motors and you cannot do any work on them yourself. If they don't have any of these letters/symbols then they are not flameproof but you should contact a reputable rewinding company who will be only to happy to advise you on the suitability of the equipment you have. You will need special flameproof glands for any cabling that needs doing though the choice of cable is not so critical. The important factor here is that if anything should go wrong with one of the motors, eg. bearings seize causing a stall and overheating of the motor with possible internal short and explosion, then the reaction is contained INSIDE the motor and not allowed to escape into the surrounding area leading to a bigger explosion because of the dry and dusty conditions.

As I said in my previous post, I don't want to alarm you but I have been in the armature winding business for over 30 years and have seen the effects of a situation like this. The smallest damage to a flameproof motor can have dire consequences. Please get the professionals in. If you email me I can find a reputable company for you in your area that will advise you on the best course of action.