voltage

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dressur4
Posts: 11
Joined: May 12th, 2014, 1:59 pm

voltage

Post by dressur4 »

I am thinking of using high voltage rather than 12v I can carry a lot more power down to the ROV. i know the work class ROVs use 13,500 and more. I am thinking of 220. Has anyone else used high voltage? I have a hull design and I want to use oil filled hulls with a compensator for pressure. I want to go down real deep and my Neptunes are great with the Go Pro.. but i want to have a lot of power for currents and to move quickly. I was thinking of using franklin submersible pump motors.. but they can't go reverse. I can use pac drives and three phase motors. there are VFDs that run on 220 single phase and can give you three phase. I wish I could use those motors. they are water filled and can go real deep.. any ideas.
dressur4
Posts: 11
Joined: May 12th, 2014, 1:59 pm

Re: voltage

Post by dressur4 »

Has anyone here experimented in NON public places with 220V systems? I know voltage drop would be much less a factor if oyu go 1000 feet or less. I was scolded on the robotrov site for this question.... but someone here must have tried it. as i know the commercial ones use 13,500 and up. I am an electrician and so I know how to make waterproof high voltage terminations. thanks again.
scubersteve
Posts: 251
Joined: Jan 28th, 2013, 10:29 pm
Location: Milton, Florida

Re: voltage

Post by scubersteve »

I expect that you will be breaking new ground with this one.
Let us know how it goes and stay safe.
dressur4
Posts: 11
Joined: May 12th, 2014, 1:59 pm

Re: voltage

Post by dressur4 »

I am looking at the Hyball and the specs are 110V or 220V and state if running off a genset must be around 7200 watts. I have decided to go high voltage and it will be safe to swim around. I see divers working around ROVs and they are high voltage. I am thinking of using silicone oil or mineral oil which ever is cheaper.
rossrov
Posts: 383
Joined: Feb 28th, 2013, 5:01 pm
Location: Australia

Re: voltage

Post by rossrov »

Hi Dressur4. From your post, I looked with interest at the Franklin motors trying to find out a bit more about the fluid used inside them. Seems to be "top secret" because searching the name of the fluid on the internet yielded no results. Some sort of antifreeze/corrosion inhibitor?

Getting back to the voltage issue, because you are an electrician I guess you have had some safety education as part of your qualification. Also guessing that you may have seen a few cases of what can go wrong, unexpectedly. What sort of safety measures would you incorporate into the system? I had a look some months ago at ROV power schematics on the 'net and there are at least 2 or more levels of safety measures used, and with good reason.

If anyone Googles "shore power electrocution" they will find many tragic stories of what unexpectedly goes wrong. Very similar situation, except the dock would be the boat and the boat the ROV.

Note that the people in this article didn't need actual contact with the boat or dock to be affected: http://ecmweb.com/ops-amp-maintenance/c ... ctrocution
dressur4
Posts: 11
Joined: May 12th, 2014, 1:59 pm

Re: voltage

Post by dressur4 »

Yes I know what is in the franklin motors. it is food grade glycol. it is in case of leakage it won't compromise the well. The water/Glycol is only in the rotor section of the motor to lubricate the bearings and the thrust bearing. the field is potted in resin sandwiched between the stainless steel case outside and a stainless steel case inside. They have self healing resin in case it overheats or a surge heats the windings it will self heal. As per electrical boats are a different animal than buildings. Grounding the ROV will include an isolation transformer and other protections. Oil filled and proper electrical connections for high voltage in marine use is of course paramount. you can use water as the grounding medium but that poses potential danger to people around and wildlife that inhabits the water around the ROV and the generator Now how do i install an isolation transformer in this setup is going to be the kicker. I could use a sacrificial galvanic isolation system between the ROV and the Genset. I love isolation transformers I use the in my internet jukeboxes I build. We installed new shore ties in Connecticut for the Coast Guard I know how that works. If I could use a submersible pump with one of those franklin motors as propulsion somehow they can take on hell of a lot of pressure. I got one down 350 feet in my well. it is a huge one but never failed me and it's original to the house. and it is a Gould's I am thinking that they are three phase motors if they have a box . there are three wire motors and two wire. I am researching that now. would make great thruster motors. The ends of the motor are cast iron and lasts decades in water. I have one that was pulled from a well that was in for 40 years. Great motors. just need a way to control their speed.
dressur4
Posts: 11
Joined: May 12th, 2014, 1:59 pm

Re: voltage

Post by dressur4 »

Here is an ROV using 220v I don't feel so idiotic after all.

http://www.eprons.eu/rov_rb_mini_300.html
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olegodo
Posts: 222
Joined: Aug 30th, 2013, 9:47 am
Location: Bergen, Norway

Re: voltage

Post by olegodo »

Most commercial ROVs use high voltage.
The only danger is when inexperienced people starts using it and do a poor and improper job at taking the correct safety measurements. But if done properly it is safe, maybe the question is more how safe can we make it within the usual hobby rov budget.
This is why most people say that you should not use high voltage and rather use on board batteries. However there are people here on the forums using it and I know of college projects here in Norway that has used it.
If you feel you can implement it properly, go for it. just remember that it can be potentially dangerous.

On the other side, using lipo batteries is also not 100% safe. if physically damaged or charged/discharged properly the pose a serious fire hazard.

These are only my thoughts and I am looking forward to see your progress! :)
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