Can't find it in the 16th, or 6th ship's regs.  Am I imagining it, or has anyone else heard or know about this?



110-02-01 The Regulations do not apply to the following installations:

(iv) equipment on board ships

iirc the motor control gear is supposed to conatain specially designed overload protection

http://www.tlc-direct.co.uk/Book/7.15.1.htm mentions this

Hi RES - Long time no hear mate!
Motor start fuses are the ones you need - can't remember exactly but I think they go by 'M' rating simialr to mcbs.

Same phase fuse blowing each time? What kind of motor is it mate? Direct online star-connected?

Check the starter contacts for burning - particularly on the phase which is blowing the fuse, also check for the usual stuff - duff connections, loose tails behind the motor terminal block where the winding leads are connected, starter coil connections - if it's 415V you'll have the coil connected across 2 of the phases.
Do insulation resistance and continuity tests too.
1 ohm for winding continuity is an average reading.

Don't know much about ship's radar motors and associated kit, but is there any kind of braking by phase reversal or plugging contactors?

Let us know what you find.

TT

Hello Trician

How's life?  I did manage to fix the radar motor, it's just that it was protected by individual fuses that bothered me.  It's probably perfectly okay, but I would have preferred to see a three pole type c/d mcb.  Especially as the fuses were in the gearbox at the top a mast.

In the 6th ed 8.8 does say "In poly-phase motor circuits adequate precautions sould be taken to prevent damage due to single phasing........"   but that's about as close as I can get to what you say re the dropped phase.

However if there is no over-heating under normal use then the motor may be over rated for the weight of the armature anyway. Would have to watch it in storm conditions as there's quite a lot of leverage on one of the larger ones in a wind.

If it's only the same fuse blowing then, it may be that the axel is bent and over-stressing the coils at one phase in the rotation.

I'd recommend a swap-out of the motor and shaft unittil so it can be sent back to the manufacturers to be checked. Depends how tight the set-up is financially.............. oh for gods sakes listen to me ....... it's a ship of course there's no money for maintainance    

As I've already mentioned, I fixed the problem, it was just the the individual fusing that was of concern to me.
FYI, you are quite correct about some ship'sbudgets being fairly tight, But it's quite amazing how much money is suddenly available when the ship can't sail because his radar's knackered.

MCA are based in Southampton, and they just love to pop down the docks and check out the ship's equipment.  You should the look of delight on the old man's face when I turn up.