Post by John on Jun 11, 2015 16:26:21 GMT -5
These both happened at Angus Place in NSW.
The second longwall installation comprised of Australian made GEB's and transformers together with the FLP HV circuit breakers mounted on the transformers, all made by CMA, (Cable Makers of Australia).
The GEB's must have been made under license to B&F of Sheffield UK, as a lot of the features were identical. Anyway we had a few teething problems with the GEB's at first, there was an Isolator problem that CMA rectified, but not long after that, one of our Leading hands was opening the door of a GEB, but he had a feeling someting was wrong, both the Isolator and test switch were in the off position, but something was nagging him, so prior to putting his hand inside, he pulled out his ezscan and checked, the main chamber was still alive!! Voltage was 1100volts. How easy that could have been turned into a tragedy.
So until the problem was rectified by CMA, we had to drop the transformer circuit breakers.
Although not dangerous, I had a job on nightshift, to pull one of the transformer 11Kv circuit breakers for planned maintenance, this was pre me being a Leading hand, so the Leading Hand isolated the supply at the outbve subs, then made his way in to give me a hand "extracting" the breaker. Job complete, he gave me a hand to mount the breaker back into the FLP receptacle, all I had to do now was "bearhug" the breaker and reach around the back and reconnect the incoming and outgoing cables.
All done blind and by feel, tightening the nuts was a pain in a very confined space and taking care not to drop a nut, washer or my spanner. All done! Door closed and twenty million bolts to screw in the front door and tighten!!.
Job complete, a walk up to the pantechnicon telephone to get my leading hand to close the main breaker. I heard the noisy "no volt" coil buzzing and walked down to energise both transformers..There was an eerie bright white light coming from the transformer breaker I'd been working on, it had two glass windows, one the ammeter, the other for indications of faults, jeeze it was bright!! I ran up to the phone, luckily the Leading hand was still there, "Kill the power to the longwall and earth it, QUICK!!"
I heard the NVC drop out, phone rang, powers off and earthed, what's up??
I said" I don't know, but I'm going back in, so DON'T take the earth off and close until I request it" He said he'd hang around until he heard from me.
I opened the door, nothing looked amiss, so I reached around the back to feel each terminal, all looking good, then, one of the incoming cable shoes was loose!! I'd missed one. I pulled my hand out to check if I had any carbon on it, no, clean apart from coal dust engrained in my fingers.
Pheeeewww, that was one lucky break! Had I closed the breaker, the whole inside would have ionized.
I tightened the nut and rechecked all the others, all OK, closed the door and bolted it up again.
This time everything was perfect when power was restored, I closed both transformer breakers.All was OK.
How I'd missed one terminal, I have no idea, but I had.
The second longwall installation comprised of Australian made GEB's and transformers together with the FLP HV circuit breakers mounted on the transformers, all made by CMA, (Cable Makers of Australia).
The GEB's must have been made under license to B&F of Sheffield UK, as a lot of the features were identical. Anyway we had a few teething problems with the GEB's at first, there was an Isolator problem that CMA rectified, but not long after that, one of our Leading hands was opening the door of a GEB, but he had a feeling someting was wrong, both the Isolator and test switch were in the off position, but something was nagging him, so prior to putting his hand inside, he pulled out his ezscan and checked, the main chamber was still alive!! Voltage was 1100volts. How easy that could have been turned into a tragedy.
So until the problem was rectified by CMA, we had to drop the transformer circuit breakers.
Although not dangerous, I had a job on nightshift, to pull one of the transformer 11Kv circuit breakers for planned maintenance, this was pre me being a Leading hand, so the Leading Hand isolated the supply at the outbve subs, then made his way in to give me a hand "extracting" the breaker. Job complete, he gave me a hand to mount the breaker back into the FLP receptacle, all I had to do now was "bearhug" the breaker and reach around the back and reconnect the incoming and outgoing cables.
All done blind and by feel, tightening the nuts was a pain in a very confined space and taking care not to drop a nut, washer or my spanner. All done! Door closed and twenty million bolts to screw in the front door and tighten!!.
Job complete, a walk up to the pantechnicon telephone to get my leading hand to close the main breaker. I heard the noisy "no volt" coil buzzing and walked down to energise both transformers..There was an eerie bright white light coming from the transformer breaker I'd been working on, it had two glass windows, one the ammeter, the other for indications of faults, jeeze it was bright!! I ran up to the phone, luckily the Leading hand was still there, "Kill the power to the longwall and earth it, QUICK!!"
I heard the NVC drop out, phone rang, powers off and earthed, what's up??
I said" I don't know, but I'm going back in, so DON'T take the earth off and close until I request it" He said he'd hang around until he heard from me.
I opened the door, nothing looked amiss, so I reached around the back to feel each terminal, all looking good, then, one of the incoming cable shoes was loose!! I'd missed one. I pulled my hand out to check if I had any carbon on it, no, clean apart from coal dust engrained in my fingers.
Pheeeewww, that was one lucky break! Had I closed the breaker, the whole inside would have ionized.
I tightened the nut and rechecked all the others, all OK, closed the door and bolted it up again.
This time everything was perfect when power was restored, I closed both transformer breakers.All was OK.
How I'd missed one terminal, I have no idea, but I had.
