Bilge pump motor, coupling, going wonky during dive?

Anything to do with Propulsion.
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zpyder
Posts: 9
Joined: Sep 26th, 2013, 8:32 am

Bilge pump motor, coupling, going wonky during dive?

Post by zpyder »

So my ROV has been out for 2 test dives so far. First trip was pretty much ok.

Yesterday however, over the course of the hour it was out, the vertical thruster (johnson 750gph pump) developed a lot of vibration.

Looking at the prop,shaft etc, when I turn it slowly it's angled slightly now. Only a few mm out, but at the speed the shaft turns it's quite bad when powered. I'm 99% sure nothing hit the motor/shaft during the dive to bend it out of shape, so I'm wondering if any of you have advice on:

A: how it could go offset over a dive on its own
B: How to fix it (I don't seem to be able to get it seated straight again now)

Will I damage the cartridge if I take a pair of pliers to it and try to bend the shaft into alignment?
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Rover
Posts: 108
Joined: Jul 18th, 2011, 10:23 pm
Location: Minnesota

Re: Bilge pump motor, coupling, going wonky during dive?

Post by Rover »

Hi Zpyder.

The shafts are pretty tough, so all I can think of, is the possibility that the prop was hit and it bent the shaft, I wouldn't think an out of balance prop would bend the shaft.

At this point, you have nothing to loose, but try and bend the shaft straight with a pliers. you can try wrapping some electrical tape around the shaft so the pliers don't mar the shaft.

Rover
zpyder
Posts: 9
Joined: Sep 26th, 2013, 8:32 am

Re: Bilge pump motor, coupling, going wonky during dive?

Post by zpyder »

I ended up tweaking the grub screws on the adapter more yesterday and it seems to be ok now. I think because the shaft has a small section cut flat, during operation the adaptermust have moved/twisted a bit so that it was at an angle. It took a lot of fiddling but the shaft is straight again now. Good to know how to fix it for the future!
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