[PSUBS-MAILIST] Thruster Quote

Sat Oct 26 16:57:46 EDT 2013

Alan,

Yeah, I'm worried about heat. Keeping amps down through it is certainly a simple fix, no wonder why then the commercial builders use such high input voltages.

Ive been looking briefly but not yet in depth on DC to DC step up conversion, I'm not sure yet how that works.

Yes Carsten thank you as well, seeing examples of rejected ideas is equally as helpful as seeing the successes.

Joe

________________________________
From: Alan <alanlindsayjames at yahoo.com>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
Sent: Saturday, October 26, 2013 3:17 PM
Subject: Re: [PSUBS-MAILIST] Thruster Quote

Thanks Carsten, you seemed to have tried everything.
Joe, the higher voltage motors would have an impact in reducing the heat in the motor. 
It would lower the amperage for the same power & reduce the heat in the windings. 
The heat may be a consideration with modifying a Lewars bow thruster as you would 
have to encapsulate a motor that is designed to have some air cooling. 
As another Psubbers said " when you enclose an electric motor you are creating an oven". 
The Minn Kota would be designed as a totally sealed unit able to handle the heat 
produced in shallow, warm water operation.
The only thing I don't like about the Minn Kota is there is no thrust bearing for reverse.
Which might be OK on the horizontal thrusters where there isn't much call for reversing
them. But not so good on fixed vertical thrusters where you would be running them
as much in forward as reverse. Wonder if there is room inside them to add a thrust 
bearing.
Here is a very good article on underwater motors that states that the main cause of failure
is overheating.
www.submersiblemotorengineering.info/overheat.htm
Alan

Sent from my iPad

On 27/10/2013, at 6:47 AM, Joe Perkel <josephperkel at yahoo.com> wrote:

Jim,
>
>I've spotted these and they are very high on my candidate list. The thing that I've noticed is that the ampere usage goes up with the lower input voltages. 24 - 48 vdc is what I'm targeting.
>
>What's bothering me is that I can't seem to match the Lewmars power in a motor/reduction package at 4" (#4 Sch40) diameter without going too high on the input voltages.
>
>A pair of those 185tt thrusters @ 24v with the motors enclosed could go laterally on the stern "Shinkai" style and do the job quite nicely for main propulsion. Probably too much but, more than enough to make headway or hold station in a current.
>
>It's maneuvering thrusters that present the problem. Right now, the Minn Kotas don't look so bad, but I'm going to see what I can do with Hanks motor.
>
>Joe
>
>Sent from Yahoo! Mail for iPad 
>
>
>
>________________________________
>From: jimtoddpsub at aol.com <jimtoddpsub at aol.com>; 
>To: <personal_submersibles at psubs.org>; 
>Subject: Re: [PSUBS-MAILIST] Thruster Quote 
>Sent: Sat, Oct 26, 2013 2:59:41 PM 
>
>
>Joe,
>Here are a couple of websites of vendors which include pricing:
>http://www.westmarine.com/ 
>http://www.marinedeal.com/  The Lewmar I've pasted below is $1239 USD per the site.  It's all electric (not hydraulic), 3 hp, 92 lb thrust.  It's the smallest one they list, and they can get as big and expensive as you want.   
> 
>
>
>Model
>Hub
>Voltage 
>Power (hp)
>Tunnel Size (in)
>Thrust (lbs)
>Weight (lbs) 
>140TT2.2 Composite 12v 3.0 5 1/2 92 29  
>Dimensions
>A B C D 
>4 5/6 9 1/4 5 1/2 2 7/8  
>
> 
>-----Original Message-----
>From: Joe Perkel <josephperkel at yahoo.com>
>To: Psubbers Mailist <personal_submersibles at psubs.org>
>Sent: Sat, Oct 26, 2013 9:24 am
>Subject: [PSUBS-MAILIST] Thruster Quote
>
>
>This early interest of mine in thrusters has to do with sizing of the vehicle; I need to know what is available to me in order to make decision points before I spend the next few hundred hours on a CAD model. Below is a quote I received for an electric thruster 60 - 70 lbs @ 110 - 300vdc, and a hydraulic one 70 lbs @ 2000 psi and 2 gal/min flow rate. It would be rude of me to identify the company, this was my quote, and someone else's may be different.
> 
>Hydraulic Motor only .16 cu in displacement at 2,420.00 each.
> 
>Hydraulic Thruster complete with the above motor at 5,170.00 each.
>Thruster complete less motor at USD 2750.00 each.   This include the duct, prop, hardware etc..  Everything less the motor.  An electric or hydraulic motor can be installed onto it.
> 
>Electric Thrusters range from 9,000.00 to 11,000.00 depending on the voltage requirements, feedback requirements, etc…  I would need more info from you in able to recommend a particular electric thruster to you.  The prices do not include controllers.  Many of our customers use their own or we can recommend one to you.
> 
>This confirms for me that I am solidly entrenched in the homebuilt thruster design business.
> 
>Joe
>
>
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