Turbo-Electric Bulkcarrier

shieldrow
10th October 2011, 21:11
I was fortunate or unfortunate enough to sail on a turbo-electric bulk carrier in the late 1960s
The ship in question was the Tes "Coral Venture", a ship of contrasts in no uncertain way.

Launched in 1943 as the "Wagon Box" by the Alabama shipbuilding company Mobile Alabama as a standard T2-SE-A1 type with General Electric turbo-electric propulsion she was a tanker of about 16,500 dwt. Folowing the end of the Second World war she was purchased as war surplus in 1948 by DK Ludwig's National Bulk Carriers and continued trading as a tanker until laid up in 1957.
She was converted into a self discharging cement carrier at National Bulk Carriers Kure yard in Japan in 1963 and placed under the control of the Argyll shipping company of Bermuda and placed under the British Flag.
In 1964 she left Kure to start her new life as a cement carrier running between Grand Bahama Island (where Atlas cement had its plant) and ports on the Eastern USA seaboard.

When I joined her she was being managed by Huntings of Newcastle under contract, in fact placing the ship under the British flag was a kind of flag of convinience in reverse as our wages were nowhere near what an American crew would demand.

Joining the ship for the first time involved a long flight via New York, Miami and a short hop to Freeport Grand Bahama Island.
Departing from the plane at Freeport I was greeted by dancers in grass skirts and could see the lights of Freeport with its Casino and night life in the far distance. I was met by a fellow shipmate who loaded my belonging into the trunk (boot) of a ginourmous? yank tank and headed towards the lights!
To my dismay at the tee junction outside the airport all the yankee vacationers turned right, we turned left and after a fairly long drive along a dry dust road we arrived at a berth inside Atlas Cements plant.
Quick look at my watch indicated about 9 at night and the ship was in virtual darkness, question everyone ashore, answer No all in bed!
Welcome to the Bahamas.

The ship was a ship of contrasts, at the top of the engine room were two plaques, one said SS Wagon Box 1943, the other Tes Coral Venture Kure 1963.

What the Kure ship yard had done was basically replace the former cargo tanks with brand new cement storage and discharge gear whilst retaining the old engine room, stern, midships and bow.
The accomodation was all metal including the toilet and wash basins and was in poor condition and got very hot while lying in port waiting for cargo.
Typical sea time was one or two days at sea to Jacksonville, or Port Everglades, or port Canaveral and sometimes Bermuda. Discharge was typically 8 hours depending on cargo and up to three weeks lying in the cement company's basin waiting for cargo.
One obvious problem with a roster like above was shortage of money due to the short sea time and absolute boredom when laid up.

One thing however she was probaly the best maintained T2 in the world.
If anyone else sailed on a T2 I would be interested in your tales.

Operational wise she was quite interesting as we used the main propulsion alternator to discharge the cargo via bus transfomer supplying either fixed or variable frequency busbars.

Chief Engineer was David Rowan and 2nd was Tommy Farrel.
I have further details of the discharge gear if anyone is interested.

surfaceblow
12th October 2011, 18:22
I sailed on a few T2's over the years. The first T 2 was a Keystone tanker Chancellorsville which was built Built October 1943 by Sun Shipbuilding & Drydock, Chester, PA., as "Chancellorsville", # 370,
for Paco Tankers, Inc. (Keystone Shipping Co.), Wilmington, Del.
1961 - lengthened by replacement of cargo section with new midbody built by Mitsubishi Nippon Heavy Industries, Ltd., Yokohama and fitted by Todd Shipyard Corp., Alameda, resulting vessel 14,445 grt, 568.8 x 80.1' delivered 07/1961. 1964 - Keystone Shipping Co., Philadelphia. I was told that the Chancellorsville was the only ship that the Chief Engineer sailed on. When I reported to the ship for a medical relief the Chief did not want to accept me since I did not have T 2 experience. After the tour of the engine room I told the Chief that the plant was a nice toy. Which did not go over well with him. My last ship was some what bigger an SL7. The ship left on my watch so I had a chance to maneuver out and answer a few questions from the Chief. At the end of maneuvering the Chief told me that he did not want me to start the purifier since it was a high speed machine. I later sailed on one of SeaLand's converted container ship from a T-2.

My last experience with sailing on T-2's was when I was Chief Engineer on the Marine Floridian for two years 1982 and 1983. The Floridian started out as the SS Paoli at Sun Shipbuilding in Chester, Pennsylvania, in 1944 and was converted into a molten sulfur carrier at Baltimore, MD.

While I was on the Floridian we usually transit Galveston to Tampa with a few side trips.

Joe

shieldrow
12th October 2011, 20:59
Thanks Joe for tjhe post,
One thing I do remember about the T2s was the speed in which you could go from ahead to astern. Basically bring down the main turbine speed, pull the man-u-matic circuit breaker into the induction mode (ie no excitation), then into OFF or open. Then after a short time put the circuit breaker into astern, then apply excitation and finally increase turbine speed and the prop was turning astern. The other memory I had was changing amplydynes or rotorols which could be a pain to set up and the lousy all metal accomodation. No fancy formica or polished wood apart from the mess table on these ships!

surfaceblow
13th October 2011, 22:40
I had one problem with no excitation to the main generator just after the First Assistant Engineer secured one of the SSTG electrical while the Second Assistant secured the steam to the other SSTG. The resulting black out occurred just after departure Tampa. Normally it would not have been a problem but we were still in Tampa Bay. After restarting the plant we managed to restore the excitation only to burn out the circuit after some one opened the switchboard door to see why their was a sign on the door warning not to open while underway. We ended up running the electric welder to excite the Main Unit and using the welder rheostat to vary the excitation.

On the all metal accommodations that is required on US ships after a few deadly shipboard fires. While I was on the Marine Floridian the Deck Department stowed there Oil and Grease Drums in the space above by Office. After a while these drums started to rust along with the deck due to the sulfur and general lack of care. When I returned to my office I had a pool of oil on my desk and all of the paperwork that I was working on.

Joe

Varley
3rd November 2011, 11:56
Gents,

Perhaps an odd question for a "battery stacker" to have to ask (and strange to find T2s under bulkers) but can any of you tell me what operational checks were made before applying motor excitation?

There are some medium speed gas tankers with a get you home system using the directly coupled shaft generator as a motor.

In motor mode the synchronous machine is run up asynchronously on the damping bars like the T2s. The machines are brushless and the field stator is energised but this is prevented from being applied to the rotating field by an additional circuit on the rotor. This circuit 'looks' at the voltage across the field winding. When the frequency is low enough and the instantaneous voltage minimum it switches through the excitation to commence synchronous running.

Was any similar check done across the T2 motor field winding/sliprings before applying the excitation?

There are one or two with T2 memories here on the Island but they seem stuck with images of pet monkeys, bus bars and resulting grisly blackout.

In the few months before redundancy I had some problems with the rotor circuits frying. Having noted that better known makers employ conventional pony motor run up and synchronize across at the main stator connections I had concluded the on-rotor solution is rather 'tender'.

David V

surfaceblow
3rd November 2011, 17:58
Gents,

Perhaps an odd question for a "battery stacker" to have to ask (and strange to find T2s under bulkers) but can any of you tell me what operational checks were made before applying motor excitation?

There are some medium speed gas tankers with a get you home system using the directly coupled shaft generator as a motor.

In motor mode the synchronous machine is run up asynchronously on the damping bars like the T2s. The machines are brushless and the field stator is energised but this is prevented from being applied to the rotating field by an additional circuit on the rotor. This circuit 'looks' at the voltage across the field winding. When the frequency is low enough and the instantaneous voltage minimum it switches through the excitation to commence synchronous running.

Was any similar check done across the T2 motor field winding/sliprings before applying the excitation?

There are one or two with T2 memories here on the Island but they seem stuck with images of pet monkeys, bus bars and resulting grisly blackout.

In the few months before redundancy I had some problems with the rotor circuits frying. Having noted that better known makers employ conventional pony motor run up and synchronize across at the main stator connections I had concluded the on-rotor solution is rather 'tender'.

David V

The controls for the T2 where hand a matic. You had to have turbine speed governor lever at a sufficient speed before moving the reverse lever from the second to the third position and also wait until the induction motor speed increased and was as close to the synchronous speed. It was best to check the frequency of the motor and the turbine by switching the Frequency Meter to view each. Once you were familiar with the rpm's and pressures and by the sounds of the motor and turbine reaching a steady state you could change the settings If the speed difference was to great then the ship would start shaking violently.

Joe

Below is the instruction manual description of the control levers.

T 2 Electric Propulsion

A T 2 uses one main turbine generator set with 10 stages and a marine synchronous type motor. Control is by three levers.

The reverse lever operates contacts that complete the electrical
circuit between the generator and motor for ahead and astern propulsion. This lever also connects the generator and motor fields to the excitation circuit. There are seven positions of this lever three forward position, stop and three astern positions. In first ahead the main contacts 1,3,5 close and connect the motor and generator. Second ahead the generator field contactor 7 closes causing the generator voltage to build up and the motor to start as an induction motor. In the third position the motor field contactor 6 closes applying field to the propulsion motor and causes the motor to pull into step with the generator and run as a synchronous motor. In the astern positions the sequence is the same but the main line contacts 1,2,4 are closed that reverses the phase connection.

The reverse lever also operates three cam switches. Switch A closes in the off position of the lever and completes the circuit to allow operation of the magnetic type generator field contactor for port operation. Switch B closes in the second ahead, third ahead, and second astern, third astern positions of the lever and completes a circuit to start the motor driven ventilating fan automatically in case it has not been started. Switch C closes in the first and second ahead and astern positions to short circuit the generator exciter field rheostat to apply over excitation during starting the equipment as an induction motor.

The Turbine Governor control lever permits adjustment of the main turbine speed control. Speed range is 1080 to 3960 rpm. The slow speed position is nearest the panel and full speed is farthest away from the panel. There is an intermediate position called maneuvering.

Emergency Turbine Governor lever is connected to the turbine operating mechanism. Normal position is nearest the panel; in an emergency pulling the lever toward the operator to the stop position engages the lever ready for manual operation.

Varley
3rd November 2011, 18:34
Joe,

I am very much obliged for this description.

You say the frequencies of the motor and generator ("turbine") could be compared during starting. As the motor stator would already be connected to the generator bus conventional measurement of frequency would show the same for both. Could the motor reading have been measuring the frequency across the exciter field? Were anything like synchronising lamps fitted?

Perhaps the older technology could put up with more abuse if excitation applied with the a large induced voltage already sitting on the field winding detsruction of the rotating semiconductors doesn't surprise me.

David V

surfaceblow
3rd November 2011, 19:37
Joe,

I am very much obliged for this description.

You say the frequencies of the motor and generator ("turbine") could be compared during starting. As the motor stator would already be connected to the generator bus conventional measurement of frequency would show the same for both. Could the motor reading have been measuring the frequency across the exciter field? Were anything like synchronising lamps fitted?

Perhaps the older technology could put up with more abuse if excitation applied with the a large induced voltage already sitting on the field winding detsruction of the rotating semiconductors doesn't surprise me.

David V

It's been a long time since I have sailed on a T2 (1990's) and may have some facts confused.

There were no synchronizing lamps fitted for the Main Motor.

Originally the T 2 set up did not have a frequency meter for the Main Generator and Main Motor set up. But I have seen frequency meters installed at a later time for the setting up the Main Turbine Generator to be used for Cargo Operations.

The exciter field is DC so no Frequency reading at that point. In fact there is no excitation to the Main Motor while it is an Induction Mode. Motor excitation is only supplied when shifting to Synchronous Mode is completed.

You can hear both the turbine and motor wind up or down on each speed change with the governor control lever. It is best to wait to the whine stops before changing to Synchronous Mode.

Joe.

Varley
4th November 2011, 02:45
Joe,

Thanks again for the advice.

I have long realised that being on the plates when an expert was manoevring a T2 is an experience missing from my 'portfolio'.

The bit I still cannot grasp is that, until excitation of the motor is established, there will be an AC voltage on the field (rotor, never quite up to synchronous speed with its field winding spinning in a field from the stator) if the excitation is applied when this is at a peak then a (very?) high current will result when switching the excitation on.

This my guess a to what seems (frequently?) to be destroying the silicon stuff of the modern version.

David V

shieldrow
4th November 2011, 13:06
Joe & David V

From memory there was a damper resistor connected across the motor field which reduced the voltage being induced into the rotor by virtue of the damper winding being rotated in an AC field (stator). As Surfaceblow stated the controls were "manu-matic"and after a while quite easy to use.
I will consult my "archives" where I have a T2 main power schematic somewhere.

On modern syncronous motors with static excitation there is usually a slip frequency sensor (relay) which does not normally allow the excitation to be applied unless the frequency is very low or approaching virtual DC. In addition zener diodes are also included in the brushless package to act as surge arrestors when applying excitation.
I have had recent experience with two large syncronous motors operating at 6,600volts diving a SAG mill (2500Kw)and a Ball mill (3800Kw)at a gold mine.
The starting method was to run the motors up to nearly sync speed by a VSD controlled pony motor, apply excitation and control the pony motor speed (by VSD) to give 50Hz, adjust the excitation to give 6600 volts and using an auto-sync relay close the stator vaccuum circuit breaker. Then close an air clutch to apply load to the mill (plenty or hiss and smoking of Ferodo as clutch engages) and then when drawing near motor full load current automatically adjust the excitation to give leading power factor.
As soon as I find the drawing for the T2, I will make a jpeg and try to post it.

Shieldrow

surfaceblow
4th November 2011, 14:52
I believe that the contractors used for both the Main Motor and Generator Field has a auxiliary contract that is used for "field - discharge connection" when ever the contractor is opened to dissipate the field energy.

I have a drawing of the T 2 schematic but it is bigger than my scanner. I found a simpler drawing at: http://www.aukevisser.nl/t2tanker/id661.htm Note 6 and 7 have a discharge resister connected to the auxiliary contractor for the fields.

Joe

Varley
5th November 2011, 12:16
Shieldrow, Joe,

Snubbing the induced voltage makes sense. There would usually be a varistor at this point anyway but guess would be far below capacity required to dissipate the energy released over the sustained period of starting.

My get-you home is one of only two applications for a synchronous motor that I have seen at sea although familiar with starting them as synchronous capacitors for shaft generator inverters (when these were thyristor bridges, not required with IGFETs). The other application was one unusual offshore diesel electric vessel with all the propulsor motors synghronous but these were all pony motor started (simple starters).

The dual use of the get-you home machine explains why it must be synchronous. The reason for their use on the offshore vessel, I was surprised to learn from the yard, was commercial - the combination of pony motor and synchronous machine was cheaper than using asynchronous machines - very much against conventional expectations.

Your comment on power factor adjustment reminds me that my get-you home set up was also provided with an AVR facility for managing this as well.

When starting the rolling mill are all the adjustments made manually? A glaring feature over the last few years, as viewed from a desk ashore, is the fear that even welll qualified staff have of manoevring a switchboard in manual.

Unfortunately most shipbuilders consider that automatic synchonising removes any need to provide check synchonising facilities when operaing it manually. The combination of avoidance of manual operation out of fear and lack of fully safe fall back facilities sort of turns this into a self fulfilling prophesy.

Many thanks for your interest and information.

David V

shieldrow
6th November 2011, 06:36
David V and Surfaceblow

Most useful information, regarding the use of varistors, in the case of the T2s being built in the early forties semi-conductor devices were not that developed.
Getting back to the mills and the starting method (although not shipping still of interest I hope).
The whole sequence was automatic with the parameters being pre-set. The operator could start the mills independently from his VDU screen in the control room or independent (from local push button) to check the mill start up, in this case the clutch would not engage.

Back to the T2, I cant remember syncronysing lamps for the propulsion tubine generator, there again as it was not going to sync with anything esle no need. There was sync lights for the two 460v auxillary generators of course.
Also on the T2 that I was on "TES Coral Venture", we also had a new circuit breaker which could only be closed when the main motor was off which allowed the main generator to supply power to the new cargo discharging switchboard via a 2400v to 460V transformer for the cement pumps, air slide blowers etc

Garryo

Varley
6th November 2011, 11:46
Garryo,

I was thinking about something like sync lights rather conventional ones (actually I didn't know there was only one propulsion generator). A lamp across the motor sliprings would (I think) have indicated both approaching sync speed and optimum instant to apply excitation. But again in the era before semiconductors maybe the kit was robust enough not to worry too much about the right instant (what are arc chutes for, after all?!).

I have seen before the description of shaking and rocking when motor too slow when applying excitation.

I suspect this will have been some form of 'pole slip' (again something I have never heard but those who have say it is something never forgotten!).

Would the motor eventually settle down or did you have to return to the asynchronous stage? (suspect that it might never pull into synch if 'slipping').

It's great to find others interested in this rather esoteric topic even if it has modern day implications. I am also interested in hearing what goes on in industry ashore.

(My practice is strictly maritime. Having set fire to our chief executive's car, with him in it, following my fitting a radio one of my E/Os warned me too late to stay well away from automobiles and yachts - I was demoted to office cabin boy for a week - fortunately the boss took it as a lesson not to ask a technician to do what is more properly the task of a tradesman - fortunately he escaped Lord Finchley's fate).

When I start to bore tell me - we champions can miss the signs!

David V

surfaceblow
6th November 2011, 19:31
David V

It is best to drop down on the Reversing Lever one notch than to wait.

While the equipment was robust there have been switchboard fires while maneuvering. I was lucky having only one while in a channel and nowhere to anchor. About every 10 minutes we had to de-energize the 2300 volt switchboard and use a hand CO2 to knock down the flames. When we finally were pushed along side a dock found the fault in a coil and was able to replace the coil with a spare. I had to have the old coil rewound since there was no such thing has new old stock available.

It was also wise to check all of the electrical connections and foundation bolts for the Motor and Shaft after a shaking experience.

I can understand your frustration with radio's after the RO's where history the Third Assistant Engineer had to replace the batteries for the Radio Gear. The SITOR unit was left on the batteries by the Captain after he forgot to change back over after the monthly load test of the Emergency Generator. So the SITOR was on the battery when the Third shut down the changer and replaced the batteries. When the batteries change over and charged it was discovered that all of the memory on the SITOR was wiped out. So the Captain had to retype all of the saved addresses and message templates. Which took the Old Man a long time since he was lacking more than a few fingers on each hand.

Joe

Varley
7th November 2011, 19:18
Joe,

Thanks again. I suspected that discretion was the better part of a shaking start.

As a situation not a million miles away from connection out of phase I would have also looked at the fixing between core pack and casing (of both motor and alternator). All the books show other effects - split casings, broken couplings etc. the one thing I never saw in a book is the core pack turning in the casing. Despite its omission in the tutorials it is the one effect that I have seen after misconnection of synchronous machine - and I have seen several. It is not always obvious and maybe my sensitivity is because it was when first on the engine room staff (as I counted myself on the gas turbine ships) my chief of the day (John Benn) was particular about inspecting the one auxiliary generator alternator with the phrase "look for bright metal" and the terminal box open - in my day a PIG Siemens semi automatic synchroniser had been retrofitted to the AEG MSB but prior to this the manoevring of the diesel, when it was not dismantled into drums, had been by hand or blackout only without check synchroniser. The DG core packs on more than one of the four ships had moved.

I appreciate the TOR story - was this one left over from W/T days with R/O or designed for GMDSS (even in my R/O days it was handy when the old man would do his own typing - many submitted their copy typed anyway so doing it directly on to the paper tape - that dates me again I suppose - wasn't a big step). If I am implying that GMDSS designs would have minimised such opportunities to screw up then I apologise. Have they hell. Now everything is processor controlled (not against this if sensibly applied) but to ensure there will be a continuity of service attendance much of this has RAM support batteries - many opportunities for fouling instead of one!

Not that it is just the GMDSS and Navaids.

Had to divert a gas carrier to NZ earlier in the year because well known ER monitoring system PC wouldn't boot because the RAM'd BIOS settings were lost - about 12K USD down the drain.

(Seeing one sensibly applied would, anyway, be a surprise).

David

surfaceblow
8th November 2011, 02:41
David

"I would have also looked at the fixing between core pack and casing (of both motor and alternator). All the books show other effects - split casings, broken couplings etc. the one thing I never saw in a book is the core pack turning in the casing. Despite its omission in the tutorials it is the one effect that I have seen after misconnection of synchronous machine - and I have seen several".

I would also check the windings air gap after a shaking and over speed episode.

While I was on a Diesel Electric Survey Vessel we had a EMG Diesel Generator set that went into over speed. The over speed trip shut down the fuel and air dampers but the Roots Blower Seals were sucked in and the diesel was burning lube oil from the blower and was still getting air. We shut down manual fuel valves but the unit was still going while I was putting plastic garbage bags over the air intakes. The unit finally stopped when the Rotor Segment bolts parted and the rotor bits rubbed against the stationary winding's.

We ended up on an extended stay in Wales while the shore gang removed the generator end off the ship for repairs. While the riggers had the Generator end over one of the ALCO Main Engines when the chain fall hook broke causing the generator to fall on top of one of the Main Engine damaging the exhaust piping. At least the piping protected the cylinder heads gaskets are cheaper than heads.

Joe

Varley
8th November 2011, 12:49
Joe,

Thanks again.

Do you remember the synchronous motor rotor construction - salient pole or cylindrical ?

I have some mundane winding detachment stories. One being a directly driven shaft generator which I suspected was the huge acceleration when clutching this in with ME up to speed. The other was a whole batch of Yugoslavian machines. Worst case is when I misdiagnosed failure mode on a pair of alternators as being the same and happily sailed to a different port of refuge with the remaing machine and an Aggreko, on deck. As a matter of 'prudence' took airgaps of machine on arrival at the refuge port - not even a cigarette paper gap left! (NDE bearing had been moving axially and 'rasped' its way down the end cover - mechanical collegue reckons all three machines had been flexing uo and down at the coupling or thereabouts). A sobering experience as the voyage was almost all in the Channel.

I have never 'had' an engine with air damper trips - although I am aware of their 'need' on vessels operating in oil/gas fields. Do you think the seal failure was under the 'law of unintended consequences' or was the cause of the overspeed the 're-routed' lub oil?.

The nearest I have seen to yours was when we were unable to stop one (aero derivative) gas turbines. It had tripped while running on blended fuel (burning sh*t in aircraft engines is FUN - especially if you don't have to dirty your hands much with the fuel preparatiion). When restarting it lit-off improperly and after cutting the fuel it continued to turn slowly (relatively) with turbine outlet temperatures rising unevenly as the fuel left after the trip burned off.

2/E took protective blank from spare engine compressor end and managed to get it onto the subject engine via the plenum chamber. Whether the lying fuel burned up or if the extinguishers discharged around the gap between blank and bellmouth extinguished it I don't know. To Chief's surprise boroscope inspection showed it as clean as a whistle but with some burner can damage. After these were replaced engines lasted another trip before the oil seals failed (pretty blues flames around the breather 'precipitator').

David V

shieldrow
9th November 2011, 03:29
Varley & Joe

Just couple of quick ones one the last post.
Generally most slow speed syncronous motors are of the salient pole type whilst the high speeds are sometimes cylindrical, if you look at the rotor of a six or four pole Stamford alternator ( normally coupled to a Cummins prime mover on some Aggreko sets) you will find these to be salient , higher speed rotors used on power station sets ie 100MW types these are found to be cylindrical and usually quite long compared to diameter.

I have come across the same problem with polling and bearing problems both on motors when applying a high load and the same with alternators.
Many years ago when they first brought out AC pole change winches some ships suffered alternator problems both flexing and excitation.However the main problem is insufficient rigidity in the base or end shields, I can remember six motors driving mills in a shore based job that all had to be removed and fillets welded into the corners where the end shields met the base.

surfaceblow
9th November 2011, 03:51
Dave,

My only memory of the Motor construction was it was its form wound and you could remove damage windings from the motor. A more detail description could be found at : http://www.aukevisser.nl/t2tanker/id645.htm

On the seal damage was due to the Roots Blower was geared to the engine and a positive displacement device. The vacuum created by the closing damper had to come from somewhere. So it was a normal occurrence after an over speed to have the seal sucked in. I am always hesitant in using that term since one instructor's pet rant was "nothing in this business sucks it just flows to the lower pressure area".

Joe

Varley
9th November 2011, 12:35
Joe, Shieldrow

Joe,

Great link - short but informative and also completes the answer to my first question. Induction mode is not on the damping bars/windings or exclusively so. The rotating field winding is also short circuited to act as (or part of) the induction motor 'cage' (probably not right term here). It answers another question I was going to ask about how the motor was coupled to the shaft. At this speed the motor must have been salient pole.

I anticipated the memory of your instructor. Father was a pipeline and pumping engineer with BP and I learned very, very young that columns of water are supported by the atmosphere and are not sucked up. I am surprised you had enough overspeeds reveal the fault so clearly unless it happened when testing. If so it seems rather 'over diligent' rather like the mad sparkie who included hurling the lifeboat set into the swimming pool from the bridge as part of lifeboat drill tests!

Shieldrow,

I hadn't really grasped that the propulsion motor was directly coupled and I agree at 100 RPM it almost certainly has to be salient pole. This raises yet another question - do you know what frequency was the propulsion bus when at 100 RPM. At 50 Hz this would mean a whopping 60 pole machine. There is a paper to Google (don't pretend to understand) where author cites his data being compared with that for a 60 pole 60Hz motor developed for ship propulsion. I guess this has to be the T2's - this implies max RPM would originally have been 120 RPM.

David

shieldrow
9th November 2011, 15:23
Varley & Joe
Quick answer on the T2 propulsion motor at full speed with the frequency at 60Hz gave 90rpm, the motor being an 80 pole, yes 80 pole and from memory about 8-10 metres in diameter or 20-30ft. May have been slightly larger or smaller but still pretty big and a 2pole 3600 rpm turbo-alternator.
I will just check my discharge book.. Just checked, book says quote -"one propulsion generator set 60/62.5cycles, 4925/5400kW, 2300/2370v. One propulsion motor 6000,6600 SHP, 90/93RPM 2300/2370v and two 525kW turbo-alternators.".

surfaceblow
9th November 2011, 17:17
I just looked up in my copy of Marine Engineering Edited by Harrington which also states the Main Motor to be 80 poles. It also gives the Main Generator being a two pole. The following characteristics are given:

T2-SE-A1
Turbine Generator: 5400 kw, 3715 rpm, 2370 volts 62 cycles, 1.0 pf
Main Motor: 6600 hp, 93 rpm, 2370 volts, 3 phase, 62 cycles, 1.0 pf

T2-SE-A2
Turbine Generator: 7650 kw, 3715 rpm, 3610 volts, 3 phase, 62 cycles, 1.0 pf
Main Motor: 10,000 kw, 106 rpm, 3610 volts, 3 phase, 62 cycles, 1.0 pf.

"I am surprised you had enough overspeeds reveal the fault so clearly unless it happened when testing. If so it seems rather 'over diligent' rather like the mad sparkie who included hurling the lifeboat set into the swimming pool from the bridge as part of lifeboat drill tests!"

While the unit was not being "tested" when it failed. The DG went into over speed when the Survey Team lost the towed array that they were pulling back in.

Being an US Navy Auxiliary vessel the over speed trips were tested at least 4 times a year and some cases 6 times a year. More if the trip had to be readjusted. The norm was to pre-test the trips before the required annual classification society, USCG, and Navy and again during the witnessed test. Most of the time you could not get everybody to show up at the same time (or month) and they did not accept the other's testing.

To me a contributing factor was the engine was a modified truck diesel. Most of the top end engine parts required the use of either a 7/16 or 9/16 inch wrenches.

I fully am appreciative of the newer governor and over speed trip units that have a button to test the over speed trip at a reduced speed.

Joe

Varley
9th November 2011, 17:21
Shieldrow,

Again, great stuff and wow.

Understand there were four yards and two electrical 'leaders' Westinghouse and GE - presumably there was more than one variant in terms power. Perhaps also number of poles - don't know enough about their construction to guess at implications of this against economies of scale in keeping them identical.

David V

shieldrow
10th November 2011, 03:55
Yes you were right Varley there was two main electrical suppliers for T2s as stated a third lessor one was Elliot Electrical, not sure if they were involved with the turbine.
Being virtually mass produced it was essential that the shipbuilders standardised on design and when you consider the quick time they took to build then obviously standardisation payed off.
One T2 I think she was called Hartington Hills was constructed in something like 6-8 weeks!

Regarding standardisation or identical products I can remember looking through both Westinghouse and GE brochures while working for an American company and finding almost identical products from each company and very similar list prices. Maybe it was to do with antitrust laws or some other USA law.
When I mean similar, I mean similar for example both GE and Westinghose made air break HV contactors for use at 4160v motors, one called their product Limitamp the other Ampguard, design, dimensions and features were identical.
Obviously as they say "Standardisation pays"

surfaceblow
10th November 2011, 16:03
"a third lessor one was Elliot Electrical"
The Elliot Company of Jeannette PA was never an electrical Company it is primary a Turbo Machinery Company. I live about a mile from the plant and had many relatives that worked their. I have sailed on ships that had Elliot turbines and turbo chargers installed onboard.

Last year was the companies 100 year anniversary. The company was started in Pittsburgh PA making tools for cleaning boiler tubes. It relocated around 1914 to Jeannette PA after buying a Glass Works Plant. The attraction of the plant was over 100 acres and its gas wells on the property. For a while the company was part of Carrier making the steam turbines for Carrier's bigger Air Conditioner and refrigeration units. Presently the Elliot Company is involved with building compressors for LNG projects around the world and is part of the Ebara Group of Companies.

Joe

shieldrow
11th November 2011, 03:46
Joe

I stand corrected, I knew I had come across Elliot equipment, must have been as you say turbines. also some Nordberg diesal prime movers installed on a cutter suction dredge, maybe they also had Elliot turbos, as they say a lot of water has gone under the bridge since then.
Another US electrical company I had experience with was Beliot?, they supplied 2,000kW alternators coupled to 16 cyl EMD 645E two sroke engines.
I DO rememember these engines as under certain load conditions they would "black stack", this was at about 1700kW under heavy load conditions when the transition from the gear driven blower to turbo-charger took place. At this point the blower clutch would engage and disengage quite rapidly and with the injectors still pumping in fuel this event would happen.
This did not always take place, only when trying to accelerate a suddenly applied heavy loads. This again was many years ago and these problems have no dought been resolved by EMD on their newer 710s.

Varley
11th November 2011, 10:41
Joe, Garryo,

I'm still copying - many names I''ve not heard of so nothing to add.

I do know of two stage supercharged medium speeds having a 'black stack' issue on the way up.

I'll see if I can find that 'paper' again and see if the 60pole machine is identified.

David

Nancy McMillan
9th April 2013, 19:37
I was fortunate or unfortunate enough to sail on a turbo-electric bulk carrier in the late 1960s
The ship in question was the Tes "Coral Venture", a ship of contrasts in no uncertain way.

Launched in 1943 as the "Wagon Box" by the Alabama shipbuilding company Mobile Alabama as a standard T2-SE-A1 type with General Electric turbo-electric propulsion she was a tanker of about 16,500 dwt. Folowing the end of the Second World war she was purchased as war surplus in 1948 by DK Ludwig's National Bulk Carriers and continued trading as a tanker until laid up in 1957.
She was converted into a self discharging cement carrier at National Bulk Carriers Kure yard in Japan in 1963 and placed under the control of the Argyll shipping company of Bermuda and placed under the British Flag.
In 1964 she left Kure to start her new life as a cement carrier running between Grand Bahama Island (where Atlas cement had its plant) and ports on the Eastern USA seaboard.

When I joined her she was being managed by Huntings of Newcastle under contract, in fact placing the ship under the British flag was a kind of flag of convinience in reverse as our wages were nowhere near what an American crew would demand.

Joining the ship for the first time involved a long flight via New York, Miami and a short hop to Freeport Grand Bahama Island.
Departing from the plane at Freeport I was greeted by dancers in grass skirts and could see the lights of Freeport with its Casino and night life in the far distance. I was met by a fellow shipmate who loaded my belonging into the trunk (boot) of a ginourmous? yank tank and headed towards the lights!
To my dismay at the tee junction outside the airport all the yankee vacationers turned right, we turned left and after a fairly long drive along a dry dust road we arrived at a berth inside Atlas Cements plant.
Quick look at my watch indicated about 9 at night and the ship was in virtual darkness, question everyone ashore, answer No all in bed!
Welcome to the Bahamas.

The ship was a ship of contrasts, at the top of the engine room were two plaques, one said SS Wagon Box 1943, the other Tes Coral Venture Kure 1963.

What the Kure ship yard had done was basically replace the former cargo tanks with brand new cement storage and discharge gear whilst retaining the old engine room, stern, midships and bow.
The accomodation was all metal including the toilet and wash basins and was in poor condition and got very hot while lying in port waiting for cargo.
Typical sea time was one or two days at sea to Jacksonville, or Port Everglades, or port Canaveral and sometimes Bermuda. Discharge was typically 8 hours depending on cargo and up to three weeks lying in the cement company's basin waiting for cargo.
One obvious problem with a roster like above was shortage of money due to the short sea time and absolute boredom when laid up.

One thing however she was probaly the best maintained T2 in the world.
If anyone else sailed on a T2 I would be interested in your tales.

Operational wise she was quite interesting as we used the main propulsion alternator to discharge the cargo via bus transfomer supplying either fixed or variable frequency busbars.

Chief Engineer was David Rowan and 2nd was Tommy Farrel.
I have further details of the discharge gear if anyone is interested.
To Shieldrow,
My father served in the Navy in World War II and was a Lt. on the tanker Wagon Box. I have lots of photos of the ship and crew over the 4 years he served. Very interested actually in all the locations the Wagon Box traveled during the war. I have photos that my father my notations on so I do have some locations. Nancy McMillan

A.D.FROST
10th April 2013, 10:26
Converting 'T2's was a cheap way of getting round the 'Jones Act' because you could have a new midd section built abroard and stickit on the aft section and it was classiffied as a American built ship (eg.SEA-LAND)