Nobels Bowthuster mystery setup/chain disconnected - help!

[Plonk]

Similarly my (identical) nobels thruster is now removed for repair. Never worked, since owning the boat. The push rod in one of the solenoids was siezed solid and I damaged it whilst removing(had to drill it out). Are they and other bits available? If so where please. The rod is made of some sort of bakelite. Not very hard. Thanks.

[Odana]

Moomins are at this very moment being ferried north to Hawne Basin to commence dissection and diagnosis.

 

We will post results in due course when Master Moomin has had a good tinker.

[Murflynn]

Similarly my (identical) nobels thruster is now removed for repair. Never worked, since owning the boat. The push rod in one of the solenoids was siezed solid and I damaged it whilst removing(had to drill it out). Are they and other bits available? If so where please. The rod is made of some sort of bakelite. Not very hard. Thanks.

I suggest you look at Albright International and see if you can identify your contactor, in which case they will provide spares.

I don't know about Nobels but Vetus use Albright.

[Plonk]

Thanks Murflynn

I have had a look and yes Nobells do use the Allbright contactors! Brilliant!

[Odana]

Moomin here. The diagnosis, ignoring some very dodgy wiring, is exactly the same as Plonk. The pushrod in one the solenoids is terminally stuck. Given that it's made of some sort of composite plastic stuff, even unfeasable amounts of force won't work. It's clearly possible to buy the whole reversing contactor unit for megabucks, but what we really need is a source for just the solenoid unit for much less money. Any suggestions?

 

From the label, the the whole thing is a Rymex Tecmec SW202-N119 - makes sense too based in pictures on Ebay though all there are Albright.

 

MP.

Edited May 5, 2015 by Odana

[blackrose]

I thought Nobel thrusters were meant to be better than Vetus units. Are the ones mentioned on this thread particularly old?

[Murflynn]

Albright sell component parts unlike Vetus who charge about 150% mark-up on the complete contactor. If you do have to buy a complete new unit from Albright they are not particularly expensive.

[Odana]

We now have a part on order which the Marvellous Mr Moomin has promised to fit for us if we don't beat him in the BCN Challenge (he's on Team Tawny so has nowt to fear from us). I have learned lots about motors today and am very happy indeed. Thanks Moomins! Good to see you both too :-)

[Plonk]

I thought Nobel thrusters were meant to be better than Vetus units. Are the ones mentioned on this thread particularly old?

Mine is about 15 years old. The previous owner gave up on it, not sure when but probably a good few years ago. Also there was a good 3 or 4 inches of rainwater had got into the thruster chamber. I think that open plan solonoids and damp air don't mix well. Looking at the Albright website there are component part lists, I assume the parts are current and available. I will give them a call tomorrow.

Parts list here http://www.albrightinternational.com/files/downloads/spares/SW201,202.pdf sesms to be the one I have. Thanks again Murflynn.

[Murflynn]

when I called them a very helpful mature lady spoke to me and asked why I wanted a new contactor. When I explained she told me not to be so silly and said she would just send me the contacts because she was sure that would fix the problem. Cost about £10 instead of £100.

[bizzard]

I would have thought that two of the old stand alone starter solenoids that pre 1980's cars with inertia starter motors used could easily be adapted. One for one direction of rotation and one for the other. They are still available for around a tenner each from older vehicle electrical parts suppliers, like A.E.S- Auto electrical supplies.

[blackrose]

Mine is about 15 years old. The previous owner gave up on it, not sure when but probably a good few years ago. Also there was a good 3 or 4 inches of rainwater had got into the thruster chamber. I think that open plan solonoids and damp air don't mix well.

My vetus is 10 years old, still in perfect working order. Mind you, the motor stays dry. Perhaps yours was a poor installation.

[by'eck]

I would have thought that two of the old stand alone starter solenoids that pre 1980's cars with inertia starter motors used could easily be adapted. One for one direction of rotation and one for the other. They are still available for around a tenner each from older vehicle electrical parts suppliers, like A.E.S- Auto electrical supplies.

 

You really need two single pole two way solenoids to provide polarity reversing to motor. Wired my single direction anchor winch for such having checked the brake wasn't polarity dependant.

 

Some motors are wired for reversing with two positive connections, which would allow your suggestion to work.

[Neil TNC]

While on the subject of Nobels bow thrusters, if anyone wants brushes, you will get no joy with Aquafax, the old UK agents, as they do not now carry any stock. Marine Megastore do list brushes and some other spares, but at rather a large mark up. I got my last spare set of brushes for Earnest's puny 4HP Nobels thruster (Skoda motor) straight from Nobels in Holland. As is usually the case in Holland someone will answer your inquiry in English.

http://www.nobels.nl/diensten/eigen-producten/nobels-boegschroef.html

[MoominPapa]

 

 

 

Some motors are wired for reversing with two positive connections, which would allow your suggestion to work.

This one reverses the field with a DPDT contactor and has the amature in series, always the same polarity. The contactors are arranged so that when neither are engaged, both ends of the field are connected to each other, and to the non-earthy end of the armature. Engaging a contactor disconnects one end of the field from there and connects it to battery positive. Engaging the other contactor does the same with the other end of the field, thus reversing the current flow.

 

MP.

[by'eck]

This one reverses the field with a DPDT contactor and has the amature in series, always the same polarity. The contactors are arranged so that when neither are engaged, both ends of the field are connected to each other, and to the non-earthy end of the armature. Engaging a contactor disconnects one end of the field from there and connects it to battery positive. Engaging the other contactor does the same with the other end of the field, thus reversing the current flow.

 

MP.

 

Yes, important that only the motors field is reversed, otherwise it will rotate in same direction irrespective of polarity.

 

Sounds like it has been wired to give electro mechanical braking to the motor.

[MoominPapa]

 

Yes, important that only the motors field is reversed, otherwise it will rotate in same direction irrespective of polarity.

 

Sounds like it has been wired to give electro mechanical braking to the motor.

I'm dubious that the braking real, or deliberate. Yes, the field gets shorted, but the armature is open circuit. Surely both would need to be shorted to have a braking effect? Given that the motor is permanently connected to a water-immersed prop, it's going too stop pretty quick anyway.

 

I think the shorted-at-rest field is just a side-effect of the most economical method of using two change-over contactors to generate forward, reverse and stop states.

 

MP.

[by'eck]

Yes I was just thinking along the lines of a dynamo with shorted output.

 

On my modified anchor winch the two SPDT solenoids I installed were independantly energised by UP and DOWN switches. It was failsafe in that if both switches were inadevertantly operated simultaneously, battery positive was fed to both motor terminals.

 

IMHO using two SPDT solenoids gives more versatility of control than a single DPDT.

[markgregoryuk2000]

The shorted field winding will act as a brake as there is always some residual magnetism in the armature

[Odana]

Mr Moomin has worked his magic! We now have a thing that goes 'ggrrrrrvvvrooowwwooosh!!' on the front of the boat. This is preferable to the dead lump of motor we inherited - we look forward to testing it on the next outing.

All hail the moomins!!

[Neil TNC]

We now have a thing that goes 'ggrrrrrvvvrooowwwooosh!!' on the front of the boat.

Yes...Nobels bowthrusters are not the quietest!

[by'eck]

Yes...Nobels bowthrusters are not the quietest!

 

Beware the quiet bowthruster