rsuggitt Posted October 17, 2018 Share Posted October 17, 2018 We've been looking at the electrical wiring that is on our Bofors 40mm AA gun. A lot of it is for lighting; this is run off a 6v battery and the wiring and connectors are all (naturally) low current. We can trace the wiring runs pretty well. However..... there are some items we are not sure about. There are a couple of heavy-duty pin sockets just to the left of the ejection chute; one has a lead that goes into the centre of the revolve drum, and another lead that goes to a pretty chunky brass brass socket that is positioned just left of the ejection chute. All this is totally separate from the lighting wiring, and we have no idea what it is all for. It looks like you would plug a power supply into one part of this, and some device that needs power into the other; we have no idea why one lead goes into the revolve drum, as it is inacessible and has not electrical brushes on it. The gun is all manual.... no electric motors anywhere. I'll post some photos below. Any ideas anyone.... ? Incidentally, from info in the Terry Gander book we now believe that 'our' gun was made in Poland in about 1942 (but to the 1938 design) and was shipped to Portugal. Quote Link to comment Share on other sites More sharing options...
Surveyor Posted October 17, 2018 Share Posted October 17, 2018 That brings back memories of firing from a rolling ship, sorry can't help with the wiring Quote Link to comment Share on other sites More sharing options...
Tony B Posted October 17, 2018 Share Posted October 17, 2018 (edited) Don't know if you have seen this. Those connections could be for central predictors. Edited October 17, 2018 by Tony B Quote Link to comment Share on other sites More sharing options...
fv1609 Posted October 17, 2018 Share Posted October 17, 2018 There may be some coverage in EMER RADAR & FCE K 460-469 Control Gear for Equipment 40/70 AA L3. I'll take a look when I get a chance. Quote Link to comment Share on other sites More sharing options...
fv1609 Posted October 18, 2018 Share Posted October 18, 2018 17 hours ago, fv1609 said: There may be some coverage in EMER RADAR & FCE K 460-469 Control Gear for Equipment 40/70 AA L3. Thought there might be something there but nothing, so I need to dig out EMER ARMAMENT B 520-529 40/70 AA Equipment Ordnance, QF, 40/70 Mks 1 & 2 on Mounting & 40/70 AA, Mks 1 & 2. Quote Link to comment Share on other sites More sharing options...
rsuggitt Posted October 19, 2018 Author Share Posted October 19, 2018 (edited) On 10/17/2018 at 7:04 PM, Tony B said: Don't know if you have seen this. Those connections could be for central predictors. Thanks, I found tht a while back. Unfortunately, it doesnt show those connectors. I think our model of gun pre-dates the use of external predictors (such as the Kerrison, Sperry, or Vickers predictors). It has a predictor (or more accuratly, a corrector) mounted near the azimuth operator. Edited October 19, 2018 by rsuggitt Quote Link to comment Share on other sites More sharing options...
rsuggitt Posted October 19, 2018 Author Share Posted October 19, 2018 20 hours ago, fv1609 said: Thought there might be something there but nothing, so I need to dig out EMER ARMAMENT B 520-529 40/70 AA Equipment Ordnance, QF, 40/70 Mks 1 & 2 on Mounting & 40/70 AA, Mks 1 & 2. Many thanks for that... I've not encountered that document/manual before. Might it also cover the operation of the 'Bofors Speed and Course Sight ' or 'Bofors Corrector Sight' ? Quote Link to comment Share on other sites More sharing options...
fv1609 Posted October 19, 2018 Share Posted October 19, 2018 More likely it would be in EMER INSTRUMENTS, I'll have a look. Quote Link to comment Share on other sites More sharing options...
fv1609 Posted October 19, 2018 Share Posted October 19, 2018 7 hours ago, rsuggitt said: Might it also cover the operation of the 'Bofors Speed and Course Sight ' or 'Bofors Corrector Sight' ? I don't have a lot of EMER INSTRUMENTS but looking in the Index A 000 the only Bofos reference is B 540-549 Carrier, dial sight (Bofors) M 109. I'm not into armaments so have no idea if that is relevant, I do actually have the Technical Handbook that appeared in the earlier series EMER INSTRUMENTS & SEARCHLIGHTS B 540- 544. Could do a page or two from that if you think it would help. If that is not relevant, is the instrument given any other designation that might be used in other guns? Quote Link to comment Share on other sites More sharing options...
rsuggitt Posted October 20, 2018 Author Share Posted October 20, 2018 15 hours ago, fv1609 said: I don't have a lot of EMER INSTRUMENTS but looking in the Index A 000 the only Bofos reference is B 540-549 Carrier, dial sight (Bofors) M 109. I'm not into armaments so have no idea if that is relevant, I do actually have the Technical Handbook that appeared in the earlier series EMER INSTRUMENTS & SEARCHLIGHTS B 540- 544. Could do a page or two from that if you think it would help. If that is not relevant, is the instrument given any other designation that might be used in other guns? Many thanks, a page or two woul help confirm we're looking in the right place. I dont think that the sight system was used in any other guns though. Quote Link to comment Share on other sites More sharing options...
fv1609 Posted October 22, 2018 Share Posted October 22, 2018 Don't know if any of this is relevant, can't find anything that ties in exactly with your sockets. Electrical services were not just fire control but intercom, loudspeakers, heater for hydraulic oil etc Quote Link to comment Share on other sites More sharing options...
rsuggitt Posted October 22, 2018 Author Share Posted October 22, 2018 44 minutes ago, fv1609 said: Don't know if any of this is relevant, can't find anything that ties in exactly with your sockets. Electrical services were not just fire control but intercom, loudspeakers, heater for hydraulic oil etc Many thanks for those scans ! As it happens I'm just about to go off on vacation, I'll take a close look once I'm back. Quote Link to comment Share on other sites More sharing options...
ackack Posted August 12, 2019 Share Posted August 12, 2019 We had a Bofors many years ago and it was covered in wiring and junction boxes, drive motors etc. It came from Portugal. Quote Link to comment Share on other sites More sharing options...
watercart Posted February 19, 2020 Share Posted February 19, 2020 This one is set up for the No.3 Kerrison Predicter, with electric hydromotors for traverse and elevation. Very original. I have the Predictor and the hydromotors, but yet to fit them to a gun. There is a lot of wiring and electrical stuff out of sight in these mountings, so it is not a simple restoration. There is also a diesel generator that comes with it, and the motors inside are marked 50 Volts, 50Hz 3 Phase. The Kerrison was literally a barn find in its original crate, but the previous owner had repurposed the aluminium gables and the telescope mounts / linkages. So I'm still looking for those bits...D. 1 Quote Link to comment Share on other sites More sharing options...
fv1609 Posted February 19, 2020 Share Posted February 19, 2020 1 hour ago, watercart said: This one is set up for the No.3 Kerrison Predicter, with electric hydromotors for traverse and elevation. Not sure what you mean by "hydrometers", they look very familiar to me & I knew them as Selsyns. I had a pair allegedly removed from an AA gun. I used them for turning my amateur radio mast. They are a sort of AC motor with stellate windings linked together as a pair & both energised by about 230v AC. Once energised turning one Selsyn transferred the message to it's partner & vice-versa. It was very strange because if the wind blew the aerial round there was an identical movement on the indoor one. If I turned the control one I could feel the identical torque as if I was turning the mast by hand. If the AC supply was cut both units became flaccid & would spin freely. Quite fun devices to use. Quote Link to comment Share on other sites More sharing options...
watercart Posted February 19, 2020 Share Posted February 19, 2020 Clive, I recall that they are called "hydromotors" in the main gun manual. These systems are usually a constant speed AC motor driving a hydraulic system (back to back pump and motor) using a swashplate arrangement (I think). It allows an infinitely variable speed output to the elevation and traverse drivetrains. I would love to get hold of the British printed Illustrated Parts List for the predictor, as it would confirm (or not) the above theory and tell me what I am missing. I do not think what I am missing out of the predictor would be hard to make, if only I knew what was missing. D. Quote Link to comment Share on other sites More sharing options...
LericheGuillaume Posted July 31, 2020 Share Posted July 31, 2020 On 2/19/2020 at 11:41 AM, fv1609 said: Not sure what you mean by "hydrometers", they look very familiar to me & I knew them as Selsyns. I had a pair allegedly removed from an AA gun. I used them for turning my amateur radio mast. They are a sort of AC motor with stellate windings linked together as a pair & both energised by about 230v AC. Once energised turning one Selsyn transferred the message to it's partner & vice-versa. It was very strange because if the wind blew the aerial round there was an identical movement on the indoor one. If I turned the control one I could feel the identical torque as if I was turning the mast by hand. If the AC supply was cut both units became flaccid & would spin freely. Quite fun devices to use. Hi, I'm french collector and I search 2 "hydromotors" because I have bofors without motors. Could you sell me 2 hydromotors (right and left) ? Thanks Quote Link to comment Share on other sites More sharing options...
Olivedrabsteptoe Posted July 7, 2022 Share Posted July 7, 2022 Anyone who has a Bofors needing electrical parts,we have a Naval chest containing many boxes of new unused parts for the Bofors electrical systems.Tim 07936 048802 Quote Link to comment Share on other sites More sharing options...
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