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Post by John on Dec 12, 2008 17:14:54 GMT -5
Another typical low face of the early 1960's. Not sure of the make of the chocks in this picture, at a guess Dobson Double 2's looking at the make up. At that time there were Gullick four and five legs, Dowty Roofmasters, Dobson Double 2, and the Wild-Desford Goal Post. The ones in the previous picture were Gullick 5 leg Seaman chocks.
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Post by alanvickers on Dec 13, 2008 5:43:06 GMT -5
John - you mention the MetroVick MU12 drill unit - I have never come across that one, however I am now wondering if the difference between the MU11/12 is the same as the difference between the MU80/81 i.e one had the busbars and isolator separated by a dividing barrier whilst the other did not. To be honest I cannot recall too much about the MU11 except that they were quite noisy.
We also had one or two MU80/81s made by British Thomson Houston, in one case with a front cover made of brass, I rather think that it was an MU80.
The only photos that I have previously seen of an air-cooled transformer was one made by Brush. What size is the one in the photo?
I was only once on a face that had powered supports and that was whilst on a visit at Seaham Colliery in about 1964. I cannot now recall what make they were.
Alan Vickers.
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Post by John on Dec 13, 2008 7:21:28 GMT -5
Can't help you much Alan, I didn't work too much on the older gear, from what I recollect, the only equipment of none NCB spec I came across was at our outbye bunker site, all the rest was of NCB spec. The photos are from the manufacturers operators manuals I obtained while I was an apprentice. Not sure of the electrical size of the transformer in the photo, but most of the early FLP trannies were from 150KVA to 250KVA. Later ones were usually 600KVA, and now shearers and face equipment are much larger probably twice that in the 1200KVA range. I worked on a 500HP shearer in Australia, they are nearing the 1000HP range now!
All faces I was on had powered supports from the early Dowty Roofmasters, to German Westphalia's in the early days to modern chockshields by Gullick and Dowty.
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Post by John on Dec 13, 2008 18:55:30 GMT -5
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Post by alanvickers on Dec 14, 2008 6:02:58 GMT -5
Thanks John - it is an interesting photo but I don't recognise it, I wonder what year that the article wss published.
In the case of the MU80 the dimensions were the same as the MU81 and the isolator was at the top of the unit as in the MU81. The difference between the two was that the MU81 had a dividing barrier between the two chambers whilst the MU80 did not so that there was just one chamber.
The problem was that if the MU80 was used at the coal face you had to cut off the supply to the busbars before any maintenance or repairs could be done on the contactor unit. In order to overcome this problem they were removed from coal face work and put to work outbye or on the surface. There were not too many in use when I started work in 1949. I will see if I can come across a photo or drawing.
Alan Vickers
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Post by alanvickers on Dec 14, 2008 6:51:41 GMT -5
John - also on the DMM website you can find an article with photo on the Reyrolle GA9 drill unit. The article also refers to the GA8 that had already been introduced.
These two GEB's were the same height and in later years there was an adaptor busbar connecting box produced that could allow the units to be bolted to NCB Spec panels, from memory the GA8/9s had to be lifted up about 2 - 3 inches to allow this. With Reyrolle's practice of having the busbars at the top and different sizes of unit it was often a problem when ligning up utits of different type - e.g. if you wanted to line up a GA8 or 9 with a GA6 lighting transformer you had to lift the GA8 about 10 inches.
Reyrolle also produced a small 300watt lighting transformer type GA?? that that could be bolted on to the GA8 or 9. The disadvantage with this unit was that, in theory, you had to isolate the busbars before you could withdraw and/or replace the fuse, also the unit was not proveded with a switch.
The GA8s used overloads that were made by George Ellison, as did some other types of Reyrolle flameproof switchgear.
Looking at the photo reminds me that the Reyrolle cable glands shown in the photo for the cable suppling the busbars were not used by the former Lambton Collieries and this practice was carried forward following Nationalisation and was also carried out by the old No 2 area of Durham Division of the NCB.
Lambton Collieries had developed their own design of 'Lockgrip gland' for use with double wire-armoured, lead covered, paper insulated cablse and this was widely used on cable connecting boxes known as the D50 type that were made by British Electrical Manufacturing Company (BEMCO). A similar type of gland was made by BEMCO and supplied with the cable jointing boxes that were used on cables for 6,600 volts. From the introduction of these types of Reyrolle switchgear Reyrolle provided Lockgrip type glands of their own manufacture.
When you have a look at the varieties of GEBs that were in use it is not hard to realise why the NCB produced their specifications and so making physical sizes more or less uniform.
I have had a look in my text books and I have found quite a lot of Belmos photograpghs in the flameproof switchgear chapter of 'The Johnson & Phillips Switchgear Handbook'. I have also found a photo of the MetroVick SF1 iin the isolated position with tannk dropped for maintenance, together with a sectional drawing showing the component parts, in Virtue's electrical engineering' books. Alan Vickers.
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Post by John on Dec 14, 2008 11:41:13 GMT -5
I was pretty lucky Alan, having entered the industry at the height of mechanisation and working with relatively new equipment. We had first class training facilities and some great tradesmen to teach us the trade. I was also lucky to have seen the introduction of electronics into the industry and see coal face signalling/communications change over from simple keyed boxes operating an FLP/IS relay unit in the M/G to sophisticated full consoles with L/O indications, full face communications via transistorised amplifier boxes etc. Then seeing the upgrades from the old E/L circuits to sensitive E/L circuits. From solid neutral earthing at the transformer to free neutral multi earthing, now that was a pain in the butt! Much preferred restricted neutral and sensitive E/L! The 60's saw big changes and billions of pounds invested throughout the industry!
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Post by garryo on Mar 17, 2009 8:31:25 GMT -5
John Alan
I might be able to help with some of the old pit switchgear
Reyrolle made both then HV switchgear and LV switchgear for mines, their HV gear was oil filled and operated at 3300v or 2750v, the two main types ignoring the C range which went up to 11kV were the E type for surface and the F type for underground, the main difference between the E and the F was the fault level 75MVa at 3.3kv for the E type and about 50MVa for the F type. The Reyrolle underground range up to 650v was the G range with the GA1 as an 80amp geb, of interest the pilot voltage from memory was 24vdc and it had an internal bridge rectifier. the GA3 was a section switch and the GA9 a drill panel.
When the NCB brought out the standard for GEBs Reyrolle brought out the SG range. The SGA3 again was a section switch, SGA6 lighting transformer, SGA8 80A GEB, SGA9 drill panel, SGA10 100A GEB, SGA11 double contactor plough panel. by this time the NCB had standardised on 550V and 7.5v for pilot circuit. Wecol came on the scene in Durham in the mid 1950s as there had been a little bit of parochialism with Reyrolle being based at Hebburn in County Durham. In many sparkies eyes the Wecol gear was a better product with their P455 GEBs and F60 double contactor panel.
Other makes around included Belmos, Anderson Boyes or AB, their GEBS reminded people of ovens, M&C and of course Baldwin and Frances with their Semlos with "Matic" double break contactors.
Some less familiar gear included Allen West, Switchgear and Cowans, Met Vic MU81s and Erskine Heap.
Cheers
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Post by John on Mar 17, 2009 9:34:40 GMT -5
John Alan I might be able to help with some of the old pit switchgear Reyrolle made both then HV switchgear and LV switchgear for mines, their HV gear was oil filled and operated at 3300v or 2750v, the two main types ignoring the C range which went up to 11kV were the E type for surface and the F type for underground, the main difference between the E and the F was the fault level 75MVa at 3.3kv for the E type and about 50MVa for the F type. The Reyrolle underground range up to 650v was the G range with the GA1 as an 80amp geb, of interest the pilot voltage from memory was 24vdc and it had an internal bridge rectifier. the GA3 was a section switch and the GA9 a drill panel. When the NCB brought out the standard for GEBs Reyrolle brought out the SG range. The SGA3 again was a section switch, SGA6 lighting transformer, SGA8 80A GEB, SGA9 drill panel, SGA10 100A GEB, SGA11 double contactor plough panel. by this time the NCB had standardised on 550V and 7.5v for pilot circuit. Wecol came on the scene in Durham in the mid 1950s as there had been a little bit of parochialism with Reyrolle being based at Hebburn in County Durham. In many sparkies eyes the Wecol gear was a better product with their P455 GEBs and F60 double contactor panel. Other makes around included Belmos, Anderson Boyes or AB, their GEBS reminded people of ovens, M&C and of course Baldwin and Frances with their Semlos with "Matic" double break contactors. Some less familiar gear included Allen West, Switchgear and Cowans, Met Vic MU81s and Erskine Heap. Cheers I've never heard of Erskine Heap gear Garry, Allen West now own Wallacetown though. I did see the change from all the companies who became AEI, our main GEB's were Met Vicks at the face with a few Brit Thompson Houstons and AEI all becoming the same company, then the B&F's and when I got to Cotgrave loads of Wallacetowns or "Wecols" as they were better known as. As Trev reminded me, we did have some old Reyrolle equipment at Clifton in the 60's dating before NCB specs came into force. I believe the boxes powering the Crawley stage loader and outbye bunker were old Reyrolles, large upright simple stuff that causes modern electricians grief! When I was at Brit Gypsums Marblaegis Mine, we used anything going for the main belts, anything the company could pick up cheap from the NCB!! There was one I'll always remember, a Joy NCB spec GEB! The only one I ever saw anywhere, still in it's orange livery too!
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timl
Trainee
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Post by timl on Sept 10, 2009 1:35:16 GMT -5
I remember the Belmos KF2VD (I think) Starters we used on belts and manriding haulages. We had to split the thing into 2 pieces to get it down the pit and to the job. On the job, after we put the 2 pieces back together, the apprentice (me) had to crawl inside and re-connect the interconnecting wiring. Only problem being that someone else had originally disconnected it.
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Post by John on Sept 10, 2009 7:49:55 GMT -5
I remember the Belmos KF2VD (I think) Starters we used on belts and manriding haulages. We had to split the thing into 2 pieces to get it down the pit and to the job. On the job, after we put the 2 pieces back together, the apprentice (me) had to crawl inside and re-connect the interconnecting wiring. Only problem being that someone else had originally disconnected it. Not familiar with those, probably after my time, last Belmos gear I worked with was the KFG's, they were used at Boulby to power the 3.3kv Heliminers. Then before that the last KFD's I worked with was way back in 1968 at Cotgrave Colliery.
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Post by oldshaftman on Sept 18, 2009 16:18:55 GMT -5
i know this...putting 3.3kv cables into the shafts and hanging themto the shaft wall required a lot of planing + muscle...
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Post by John on Sept 18, 2009 17:39:59 GMT -5
i know this...putting 3.3kv cables into the shafts and hanging themto the shaft wall required a lot of planing + muscle... You should try handling 11Kv cables, now I'd bet they are a pregnant dog to hang in shafts! Due to the higher power used underground, voltages went to 6.6Kv and now 11Kv is common.
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Post by erichall on Apr 30, 2011 4:27:01 GMT -5
Regardng one of the earlier posts regardiong starting of motors simultaneously, many may not be aware of the charging of electricity to mines. The meters at mines were unlike the ones in your own home which simply record the amount of electricity used. The ones in commercial use depended not just on the amount used but on MAXIMUM demand. The CEGB had a duty to provide the maximum amount necessary to run the enterprise. This meant that there was an indicator on the meter to recordthe max. demand as well as the total used, and the cost was based on both these factors. This meant that, if every motor in the mine was started simultaneously, the max.demand shot up. and this applied for the full quarter. Thiswas the reason why the E.E. tried to ensure that large starting demand motors such as fans, winders, large conveyors etc, were never started together.
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Post by John on Apr 30, 2011 7:48:52 GMT -5
I often wonder what the monthly electric bill would be for a large mine, operating large HP winders, large trunk conveying system, and a large capacity face or two faces and developments. I did a rough estimate based on guesses that Boulby Mine cost five pounds per wind on the No2 shaft, smaller of the two winders. That was around 1977. Probably way off. Nobody seemed to bother too much, as it was pretty common to wind one or two men in or out without any worries. Not much choice with me, I rode many times alone to correct problems with the skipping equipment on No1 shaft. I even had the odd ride early at the end of a shift on the manriding deck of the skip, under 20 tonnes of mineral! Just one of the perks of being central area electrician, yeah, I know the Inspector would have done a war dance had he known... ;D
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Post by Wheldale on Apr 30, 2011 13:41:04 GMT -5
I remember when I studied engineering, wasnt power factor the ratio between apparent power and actual power used? I remember the lecturer saying to have different start up times etc to keep your costs down as you were paying for electric you wasnt using. Like Eric was saying you didnt want too many piece of heavey equipment starting at once.
I remember when I was in South Africa. When I was doing my onsetter course the winding engineman showed me the clutching operation of the winder. Procedure was than when you had altered the position of the skip/cage you had to apply full brakes to the drum then apply full power to the drum to try and make it turn! The winder driver told me then (1998) it was 4000 rand (about 400 quid) in electric charges just to do the procedure.
It would be really interesting to find out all the running charges of a mine!
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Post by John on Apr 30, 2011 14:00:41 GMT -5
You're quite correct power factor is an important issue, most collieries did their best to maintain as close to Unity as possible, or they'd be paying for "apparent" power. Two ways to correct a lagging PF, one is to use a synchronous motor, usually chosen to drive the main ventilation fan, normally called an auto synchronous motor, it's excitation can be altered to suit whatever PF the pit has indicated on the main switchboard. The other method is to install "static capacitors" close to the main load, usually underground and on the coal prep plant.
I saw clutching done several times at Boulby after rope changes, never gave much thought to the actual cost of carrying it out, other than lost production while the engineman was doing it. Usually around five minutes on a bad day. But multiply that several times a shift during the first week or so of new ropes being installed.
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Post by Sam from Kent on May 1, 2011 6:10:01 GMT -5
Power Factor and Maximum Demand, seems a lifetime away learning about that doing Technicians certificate. I remember there was an alarm in the electricians shop which went off when the load was reaching Maximum Demand. I also remember no one did anything about it!
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Post by John on May 1, 2011 6:39:46 GMT -5
Power Factor and Maximum Demand, seems a lifetime away learning about that doing Technicians certificate. I remember there was an alarm in the electricians shop which went off when the load was reaching Maximum Demand. I also remember no one did anything about it! Not much anyone could have done without the Managers wrath coming down on them. The only thing I recalled was the PF meter, which was checked several times a day, on day shift of course, nobody on the back shifts bothered with it. Thinking back, the amount of stoppages, when the belts restarted up, three faces started up, probably at roughly the same time, so it makes me wonder if all pits came under the maximum load penalty??? Or just very large collieries?? Clifton bought it's power from the EMEB, as did Cotgrave I think. I was only at Cotgrave for part of my last year with the NCB, but they operated five faces, all with two shearers on them, one the main shearer, and the other being a sumping shearer to eliminate the stablehole in the tailgate. Their power usage must have been phenomenal. Plus of course, three tower mounted winders.
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