#### Re: [Amel Yacht Owners] Bow thruster Problem

kimberlt <kimberlt@...>

I believe the calculation is in error.

1 horsepower running is 746 watts. 10 hp= 7460 watts divided by 24 volts
equals 310 amps while running.

The starting load could be as high as 590 amps.

If I remember from our training class it was mentioned to use the thruster
for no more than 10 seconds at a time.

I don’t believe there is a fuse on the bow thruster.

Fair winds,

Eric

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From: Hanspeter Bättig [mailto:hanspeter.baettig@bluewin.ch]
Sent: Thursday, April 01, 2004 10:53 AM
To: amelyachtowners@yahoogroups.com
Subject: Re: [Amel Yacht Owners] Bowthruster Problem

Dear Ian
very interesting what you mentioned.
Question? How will you messure 160 Amps on the bowhruster cabels? With the
Volt-meter and the Amperemeter clamp. Such an instrument cost you about more
the 1000\$ and please calibrate it. Maybe you have a great deal with General
Electric or ABB.

Best regards and good winds
Hanspeter
SM #16

----- Original Message -----
From: Ian Shepherd
To: amelyachtowners@yahoogroups.com
Sent: Thursday, April 01, 2004 5:14 PM
Subject: Re: [Amel Yacht Owners] Bowthruster Problem

Hi Dimitris,

it sounds like you have overcooked the bow thruster through prolonged use.
If you have the 10 HP motor, it will draw around 160 amps, and with no
forced cooling in a confined space, it will get very hot after a few
minutes
operation. It is not designed for other than short bursts of operation.

The smoke will have come from the insulative lacquer on the motor
windings.
It may be OK after a cool down period, but it's now possible that the
insulation will break down sometime sooner, rather than later. From what
you
say, smoke comes from the motor as soon as you use it now, even when cold?
Is this correct? If so, you may need to get the motor rewound by a motor
repair company. I would check the current on the Link 10 when the bow
thruster is operated. If it's much more than 160 amps, you probably have
damaged the windings on the motor.

The oil should not be affected, but if I were you, I would drop the bow
thruster tube down a few inches and check to see if the shaft turns
freely.
It may just be that you have a mechanical problem which is loading the
motor
more than normal. Whilst you are doing this, check for wear around the 4
bolt holes and make sure that the countersunk screw that holds the brass
ring inside the tube is secure. What is the hull number of your boat? The
design has changed recently.

I would doubt that your insurance company would pay for a repair, but I
maybe wrong. If you say that you had to over use the thruster to save the
boat, they may be sympathetic! Good luck.

Ian Shepherd

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