Titanic's Marconi System power supply


Rob Lawes

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Having read a number of descriptions of the Marconi set fitted to the Titanic I wonder if anyone can confirm a technical point regarding the power supply.

I've recently read that the 100VDC power supply to the motor set was via a graduated switch. In order to protect the motor the system was brought up to speed slowly by stepping up the power supply one step at a time.

Once fully running, the motor starter switch was held on by an electro magnet which, in the event of a loss of the 100VDC supply would cause the switch to spring back, cutting the power to the system and preventing damage from a surge when the power supply was restored.

Does anyone know if this was definitely the case?
 
Nov 14, 2005
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From the schematic I would say your description is correct. You can see the motor starter is definantly stepped. Today that motor starter would be called a kind of soft start scheme. Always impressed with the solutions they came up with back then.
This is from a page I found. Link below if you haven't already seen it. :
The “Starter” is a standard motor starting box for direct current motors. Because there is no counter-EMF (electromagnetic force) when the motor is at rest, excessive current would be drawn if power were suddenly applied. The starting box contains resistances connected the switch steps. The switch arm is spring-loaded, pulling it in an anti-clockwise direction. To start the motor, the operator would slowly turn the lever clockwise, against the spring tension, permitting the motor to build up speed as the resistance is sequentially lowered. When the lever is moved to the end of its travel, the resistance is entirely cut out, and the lever retained in position by the small electro-magnet shown. Since the electro-magnet is in series with the load (the motor), if the power cuts out for even a moment, the lever will snap back to the off position at left. This prevents full power from suddenly appearing at the motor when the current comes back on.

The “Field Regulator” is a similar stepped resistance that controls the field current of the motor, and thus its excitation. It is a speed control, and in this case, serves to adjust the A.C. voltage produced by the converter.


schema_ TITANIC1.jpg
 
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Rob Lawes

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Many thanks for the responses Steven and Stephen.

It seems to confirm exactly what I was reading and looking at in diagrams.

I think this bit of information is really important because it could potentially help to understand what was going on in the Marconi office towards the end.

Harold Bride gives conflicting accounts between the US and British inquiries. In the US he says the system worked perfectly until the end while in the British inquiry he says that the spark was fading towards the end until they had no spark.

There is also evidence that Titanic's signals cut out suddenly.

I haven't put all this together yet but I think it's possible that the power supply to the Marconi office failed at some point near the end.

This may explain some of the events that took place and also explain why the operators thought that the engine room had flooded.
 
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These face plate starters were common on DC ships when I first went to sea. Here's a schematic and instructions for starting a motor from an article I wrote on starting up the Queen Mary from cold.
Pretty much whats in most autos today for fan speed control on your heater or A/C. If it aint broke don't fix it.
 
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Many thanks for the responses Steven and Stephen.

It seems to confirm exactly what I was reading and looking at in diagrams.

I think this bit of information is really important because it could potentially help to understand what was going on in the Marconi office towards the end.

Harold Bride gives conflicting accounts between the US and British inquiries. In the US he says the system worked perfectly until the end while in the British inquiry he says that the spark was fading towards the end until they had no spark.

There is also evidence that Titanic's signals cut out suddenly.

I haven't put all this together yet but I think it's possible that the power supply to the Marconi office failed at some point near the end.

This may explain some of the events that took place and also explain why the operators thought that the engine room had flooded.
Your Welcome Mr. Lawes. Its an intersting subject. If it did fade and got weaker it sounds like the dynamos spun down. Only other thing I could think of might be the circuit was slowly getting flooded and shunting power back thru the return before it got to the load. I will have to go re-read about it because from what I remember all this happened in the last few minutes before it went dead. Would have been interesting to watch the volt meter over time to see a possible clue. But either way I consider the sparks hero's for staying with it as long as they did. They knew what was up.
 
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Rob Lawes

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Mr Lawes? LOL, just Rob is fine.

In Harold Brides statement submitted to Mr Cross of the Marconi Company on the 27th of April he states that at one point, the Captain came in and told Bride and Phillips that the ship was sinking fast and would not last much longer than half an hour.

After this, Phillips goes outside and sees that the Well Deck is under water.

I'm wondering if when the Captain came in, he also told the operators that the boiler rooms had been evacuated which took place around 01:20, and he didn't know how much longer they would have power. If the ships supply fluctuated then it would could cause the operators to believe the engine room was flooding.

In New York, and in his letter to Mr Cross, Bride states that they had power right up to the very end and that they were ready to switch to the emergency power supply but didn't need to.

That doesn't really fit with the UK statements which suggest a gradual loss of power however, that gradual loss is unlikely because as soon as the motor starter switch magnetic hold on de-energised the AC motor generator would have instantly switched off and prevented the generation of a spark.

This would be more consistent with a report that Titanic's signas suddenly stopped. They would have to be transmitting a message for someone to notie this.
 
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Ok Rob. Didn't mean to get all formal and such. :) I will have to dig in deeper when I can on this. Been a long time since I did that. Theres so many variables that could come into play. Example: At what voltage did the magnectic hold release. Was it 90v...70v? The dynamos could have been spinning down and the motor starter didn't trip until it reached its set point. Did they ever mention resetting the switch? Lots of questions. Another question. I could be mistaken but didn't some station or stations report Titanics signal was getting weak at the end. I thought I read that somewhere but could be wrong about that. I need to pull up the time stamps on the messages like “We are putting passengers off in small boats. Women and children in boats. Cannot last much longer. Losing power.”
And the last message about the engine room flooding when the signal was lost. As I said before...interesting. I got those message quotes from the article linked below.
 
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Stephen Carey

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Many thanks for the responses Steven and Stephen.

It seems to confirm exactly what I was reading and looking at in diagrams.

I think this bit of information is really important because it could potentially help to understand what was going on in the Marconi office towards the end.

Harold Bride gives conflicting accounts between the US and British inquiries. In the US he says the system worked perfectly until the end while in the British inquiry he says that the spark was fading towards the end until they had no spark.

There is also evidence that Titanic's signals cut out suddenly.

I haven't put all this together yet but I think it's possible that the power supply to the Marconi office failed at some point near the end.

This may explain some of the events that took place and also explain why the operators thought that the engine room had flooded.
I didn't put much credence on the message saying that the engineroom was flooding, as the Marconi men wouldn't have known the difference between a boiler room and an engineroom, and as they were at their post for the whole of the sinking, just stated that rather than saying the ship was sinking. It did surprise me some of the things they were saying - probably getting a bit panic stricken by that time! As we know, the boiler rooms progressively flooded as the ship went down by the head. With the auxiliary/emergency dynamos running (which were well above the waterline), they only needed the auxiliary condenser and its two pumps (seawater and air, both steam driven) plus a supply of steam to keep them running. Why the spark was getting weaker towards the end I don't know, but they did have an emergency set I believe, that ran off batteries? It could be that flooding below had shorted out the main supply to the MG set so they changed to the emergency one? Not sure about that.
The dynamos would keep going until either the auxiliary suctions came out of the water (like the main ones did) - which didn't happen - or the main steam line fractured when the ship broke in two. The decaying steam pressure could have been the result of the lamps "glowing" as the dynamos wound down. By that time the radio room was evacuated I believe.
The engineroom was not flooded until the ship broke in two in way of the forward bulkhead and boiler room No1, as evidenced by the engines on the bottom with their LP cylinders missing.
 

Rob Lawes

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Yeah, I don't believe the engine room flooded and have a suspicion that the "engine room getting flooded" or "engine room full up to the boilers" may have been a corruption of something they were told by Captain Smith on one of his visits to the Wireless office.

Also, regarding the emergency dynamos, I understand that the Marconi system could be fed from the main dynamos or from the emergency ones. Another reason why I'm interested in the Motor Starter fly back is because in order to change over the power supply from the main to emergency switchboard they would have needed to cut the supply to the wireless necessitating a restart of the system however Bride makes no mention of this happening.

There is however, an additional visit by Captain Smith to the Marconi room that sometimes appears in Brides recollection of events. In one description he talks about the Captain arriving in the Marconi office and telling the operators to be prepared to send a distress message and then he returns a short while later to tell them to send the CQD and gives his calculated position. Could the first visit have been to inform the operators they were about to switch over to the alternative power supplies?

The emergency dynamos supplied a 500 lamp emergency lighting system throughout the ship. The stoker's believed thst when the stokeholds went dark the engineers were changing the lighting over to the emergency dynamos. The problem with this theory is that the emergency lighting could be turned on straight away from the emergency dynamos without the need to turn the main lighting off. Also, at the time the boiler rooms were dark, witnesses state the lights were on in the passageways and engine rooms and no one else outside of the boiler rooms talks of the ships lights going out.

All this leads me to wonder, apart from the emergency lighting, what systems were connected to the emergency dynamos?

The lack of any mention by Bride of the need to restart the set makes me wonder if it was being powered from the main switchboard for the entire time?

It also indicates how little water there may have been in the after end of the ship if the current paths to the Marconi room were working right up until late in the sinking.
 

lucykathleen

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maybe it falls out

why maybe a man stoker orsomethingsteped in and want jack lifebelt... maybe he want not that jack funkedmessages out...
 

lucykathleen

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Ok Rob. Didn't mean to get all formal and such. :) I will have to dig in deeper when I can on this. Been a long time since I did that. Theres so many variables that could come into play. Example: At what voltage did the magnectic hold release. Was it 90v...70v? The dynamos could have been spinning down and the motor starter didn't trip until it reached its set point. Did they ever mention resetting the switch? Lots of questions. Another question. I could be mistaken but didn't some station or stations report Titanics signal was getting weak at the end. I thought I read that somewhere but could be wrong about that. I need to pull up the time stamps on the messages like “We are putting passengers off in small boats. Women and children in boats. Cannot last much longer. Losing power.”
And the last message about the engine room flooding when the signal was lost. As I said before...interesting. I got those message quotes from the article linked below.

so 2.17 am or later was the last message 2.35 sank the titanic..
 
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Rob, Stephen you guys ask some interesting questions. I'm dealing with an engineering problem of my own so when I get time I will look into more if you haven't already found the answers . But here goes 1. As to the emergency generators being able able to feed the radio I haven't found anything definitive. Seen statements that said yes and no. There were 2 with a total of 60KW. Besides the lights they also ran other equipment..pumps ie. The 5KW radio would have used up a good portion of that. Would need to add up the loads to see if 5KW was available without using load management. 2. We know they didn't use the back up radio (no time left after the main failed) and I've never read any statements saying they switched power power supplies if they even could. Rob I found an interesting comment on one of Parks older websites that might be inline with some of what your searching for. From the same link in the post above, message at 2:10:
Virginian hears 2 v's signaled faintly in spark similar to Titanic's (Most probably Phillips was transmitting a test signal whilst Bride adjusted the main transmitter motor-generator field regulators to compensate for the dying power supply from the engine room).
3. When it comes to Titanic's radio's I always try to seek out Park's info first as he's done ton's of research on it. Unfortunately its seems he has scrubbed pretty much everything off the net. Not sure why but I remember reading his sites were attacked at one time and he had virus problems. But whatever reason I understand he has a fakebook page. I don't use that but maybe someone who does (Aly) could go there and ask him about the aux power. I myself would like to find out.
4. More and more the older sites with a lot of good info is disappearing from the web. I keep finding I have to go to the Wayback machine to retrieve it. The internet is getting more and more messed up. Soon that could even be gone so I've been saving much in my own files. Well I have to crawl back under the Willys so I'll dig into this stuff more later. Most interesting.
 
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No sorry I don't have or ever seen them. But if you look at post #14 in the link below maybe John could help you. Might be worth a shot to ask him. Cheers.
 
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Rob Lawes

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The 5KW radio would have used up a good portion of that. Would need to add up the loads to see if 5KW was available without using load management.
Hi Steven, I have been wondering the same. I'm fairly sure load management was a concern as Greaser Thomas Ranger was asked to go into each stokehold fan room and trip the fans. I read that they took up a considerable amount of the load from the main switchboards.

I agree with you regarding the Internet. It is a shame to see all of this information just fade away.

As for the comment regarding the failing power, this brings me back to my question of at what point the motor starter coil would fly back?

I've always thought 02:17 was a bit too late in the sinking for that to be the moment the last message was sent.
 
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From what I understand the loads had to be switched in manually on the aux power system...pumps, winches ect. Maybe the fans where off a branch circuit that fed something else so they had to turn them off locally. Would be so nice to find a good schematic or even just a one-line diagram of the ships electrical. Yes 2:17 does seem late in the game. From what I gathered Titanic's radio had sort of a musical tone to it compared to other systems. Maybe it was recognizable by other operators? Also looking around I found out that the radio systems installed on the ships might be a little different from each other as they were custom installations...not a cookie cutter system. Basically the same but the installers might tweek or change things to suit them. So what is on the Britannic might not be the same as the other 2. The flyback is an interesting question to me also. I don't know the particulars of how it worked. I would think the value would be adjustable to when it tripped but can't say that for sure.
 
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Rob Lawes

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I can't stretch to the cost but I'd be reasonably certain that there would be some wiring schemes and drawings in a set of books called "The SHIP Magnificent" which is probably the most comprehensive guide to the ships construction.

I agree regarding the development and installation of the Marconi sets. I think the technological development of the equipment was occurring reasonably rapidly at the time therefore as lessons were learnt from one instillation they would be applied to the next and so on.

According to studies of the visible parts of the Titanic's Marconi System in the wreck, the DC supply breaker is open and the AC supply side closed.

It's slightly amusing to think one of the operators turned the system off as they were leaving the office which would have been a completely pointless operation with the ship having minutes left on the surface.
 

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