This sounds similar to the setup I have but with a #40 motorcycle chain. I know someone tried this with a synchronous drive belt like on a Harley and he said it made an auful rachet when he tried to run it with the motor attached. So he always takes the belt off when running the diesel. I always disengage the electric motor too when switching to diesel. There is a lot of inertia in the rotor of the electric motor and my fear is the startup of the diesel will try and accellerate the motor too fast and break the chain. At least with a drive belt it only makes a lot of noise until the rotor comes up to speed.
Another thing to be concerned about is running your diesels transmission in neutral when pushing the boat with electricity. I've been told some makes of transmission really don't like this and you can ruin them. I have a BorgWarner Velvet drive and was told this was one that was OK to run in neutral and so far it has worked well although the transmission does heat up as much as it does with the deisel running because I have taken measurements with an infrared thermometer during operations.
Here is a pic of my setup although not the best angle. You can see the V-drive line with the 6" sprocket if you look real close in the upper left quadrant of the pic. This 9 hp golf cart motor on stearoids pushes my 20 ton boat smooth as silk up to 5 mph with a lot less noise and vibration than the diesel did but sadly with a lot less reserve power as well. I used the trottle on the diesel with a Curtis 0-5ohm pot in parallel to control an Altrax 500 that operates the motor. Once the chain is removed the system defaults back to diesel and all I have to do is start it up and put it in gear. I've been too chicken to try it with the chain on.
It takes a minute or two to get up to speed and I can cruise the ditch at 4+ mph on about 80 amps barring excessive headwinds. That extra 1 mph takes another 50 amps and uses too much power so I usually just go slower. With the solar I can run all day at 80 amps. But there have been occations in extrame weather when I really needed MO POWER and have made the switch to diesel on the fly. It does take 30sec to a minute so I have to make the transition in the right spot at the right time. Instantaneous switch over would be nice and I've been looking for the right clutch to install but havn't found anything yet.
Carter
From: Mark n Angela <mstafford@natca.net>
To: electricboats@yahoogroups.com
Sent: Friday, July 20, 2012 6:31 PM
Subject: [Electric Boats] Re: In-line electric motor as backup power
To: electricboats@yahoogroups.com
Sent: Friday, July 20, 2012 6:31 PM
Subject: [Electric Boats] Re: In-line electric motor as backup power
DRHitch,
I am doing something similar with my H55. I installed an 8" diameter toothed sprocket on the 1.25" drive shaft just aft of the new diesel engine and transmission, and immediately behind the shaft coupling. I chose the Eagle NRG Helical Offset Tooth design for quietness, durability, self-alignment, efficiency, and minimal maintenance requirements. Not a V belt, but V teeth.
I will fixed-mount my electric motor above that; if the prop shaft is spinning, the electric motor will be spinning. A clutched or swing engagement system seems excessive, since a free spinning electric motor adds little parasitic drag, yet is always ruggedly ready.
I have not sea-trialed yet.
Mark Stafford
--- In electricboats@yahoogroups.com, "DRHitch" <drhitch@...> wrote:
>
> Bear with me if this sounds strange:
>
> Has anyone created a "swing-in" motor mount that is PARALLEL to the prop shaft and pivots in to engage a gear tooth in the prop shaft?
>
> Assume your main power plant fails.
> In the prop shaft, there is a coupling between the aft stuffing box and the motor/transmission.
>
> I am considering the following scenario.
>
> 1) Open the shaft coupling, and remove the aft-facing half of the coupling. Slide a gear over the shaft, and re-attach the motor coupling to the shaft. Re-attach the two halves of the coupling together...At this point you have a spinning gear tooth on your prop shaft.
>
> 2) Now, in parallel to the shaft, install an electric motor that pivots/tilts inwards towards the shaft and engages the gear.
>
> 3) In case of main power plant failure, you just undo the motor coupling, pivot in the electric drive, and the prop shaft now turns through this gear system....Or maybe the backup electric motor is coupled to the gear on the prop shaft via chain/belt?
>
> The reason for all this is that the main power is a steam engine and if it stops operating, I'm considering a backup electric drive system. There is no opportunity to simply drop a Torquedo outboard alongside the hull (round fantail)....sound plausible or just too weird?
>
------------------------------------
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/electricboats/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/electricboats/join
(Yahoo! ID required)
<*> To change settings via email:
electricboats-digest@yahoogroups.com
electricboats-fullfeatured@yahoogroups.com
<*> To unsubscribe from this group, send an email to:
electricboats-unsubscribe@yahoogroups.com
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
__._,_.___
.
__,_._,___
No comments:
Post a Comment