injection testing of crompton thermal overload

[Sparky 63]

Evening All,
Is there anyone that knows what tests are required when carrying out injection tests on a Crompton Thermal motor overload type CR 12 /13 model.

Thanks

Sparky 63

 

[Marvo]

What type of injection test equipment are you using?

 

[Sparky 63]

i havent a clue to be honest - i do know we have to inject 3 x full load current sorry mate

 

[Marvo]

If you're using a primary injection unit and causing the device to break under test current there's a good chance you'll cause more damage than good. I'd clarify with the manufacturers what type of testing they deem suitable before going any further. Primary injection testing isn't for the faint hearted and something I'd recommend you contract out rather than hiring a unit and attempting it yourself.

 

[Sparky 63]

the overloads are in the order of 5.5 -8 amps and 10 amps to 13amps - i know we need to carry out a cold test , a hot test and minmium time operation

 

[Knobhead]

A simple question, why do you need to injection test something that is more or less disposable?

The actual testing is simple, but I want to know why first.

 

[Sparky 63]

To ensure that the overload functions correctly, i agree why not just replace it but its out of my hands.
thanks
Sparky 63

 

[Engineer54]

First time i've ever heard of a need for injection testing of units with that sort of low current rating, and why you would need to inject 3 X the full load current to prove these thermal overload modules is beyond me!!

 

[Sparky 63]

well that maybe the case, but its what i have to undertake, i can assure it is a requirement in my new place of work!!

 

[Marvo]

Can you quote the testing requirement for us exactly as it's stated? I'm also confused as to what there is to gain from this type of testing and I still think it should be done and certified by a specialist company in conjunction with manufacturer recommendations.

 

[Engineer54]

well that maybe the case, but its what i have to undertake, i can assure it is a requirement in my new place of work!!

If that's the case then surely they will have the correct test equipment and competent people to undertake these tests....

 

[Sparky 63]

sorry i cant advise exactly how its stated- what is your thoughts on the tests please

 

[Sparky 63]

do know of what the tests are then please

 

[Engineer54]

Yes, they would be standard injection testing. With such low currents that you are suggesting some Secondary injection sets are capable of supplying and testing. Other than that, MCCB/MCB (small primary injection set) test kit could be used. Both will provide settings and values for actual tripping current and tripping times.... I suggest you look at our forum sponsors (test-meter) website for the actual test kits, i think they maybe under high voltage testing on that site. This sort of test equipment is very expensive and not the normal run of the mill testing equipment you would find that most companies carry....

 

[Darkwood]

red tape gone silly again .... why why why!!! just show your boss this thread, unless their is a massive inherent danger to public etc I can't see the justification for this and if so the motor would have secondary or more protection solutions independent of the overload to ensure redundency...'fail-safe'.. we are talking a tiny motor here so what is it exactly doing?

 

[Knobhead]

O/L units like MCB’s are batch sample tested. Once tested they’re not fit for continued service.

So do you’re tests and when a motor burns out or keeps tripping guess who’ll get the blame.

I’ve never heard of anything so ridiculous.

 

[Engineer54]

I don't think he wants to know why you shouldn't be testing them, especially way over there limit, just hell bent on doing it, cause it say's so on a bit of paper somewhere!! lol!!

It'll be a very expensive business to carry out too, if the test equipment isn't available, and with expensive results too boot...lol!!