Tuesday, June 1, 2010

Re: [Electric Boats] Re: Dufour 34 conversion, first sea trial

 

Mark, it is a separate Kelly meter, it reads directly from the Controller.  I have to check if it is a wiring problem or a defective meter.  I guess I'll soon be buying the PakTrakr meter for redundancy.

Some updates: I've contacted Mars about the motor temperature and these are excerpts from their prompt response (the belt part is regarding one of my questions):

The ME0709 is a Brush-Type dc motor.  It is capable of 100 amps DC continuous, 300 amps for 1 minute.  At 72 VDC, you will be getting 7.2 KW input, or about 8.2 hp output.  The motor is qualified at 100 amps continuous for 1500 hours of use.  The Brush Holder can be changed very easily without dismounting the motor from the application.

Please note that our motors have winding insulation that is rated for 300 degrees F continuous.  If you were touching the motor case, and you can hold your hand on it for longer than 3 seconds, it is below 140 F.  The motor case temperature can get to 200 F before the windings are close to 300 F.  Heat in the windings due to the winding resistance is the major factor in the motor losses.  A tight belt may contribute some heat due to friction in the bearings, but you would see the grease from the bearings coming out if this was a problem.  We use high-temperature grease in the bearings (180 F).

[the ME0709] has the same insulation rating of 300 F continuous.  A temperature of 200 F on the motor case is acceptable.  If the motor gets that hot, then I would recommend a guard on over the motor case to prevent a burn from an intermittent touch.

I should highlight that through the whole design and implementation process I was in regular contact with Kelly's tech support and they have been extremely responsive, taking the time to thoroughly discuss options, and revise my wiring diagrams and proposed throttle/reverse controls.  This was great as their technical docs are on the "light"side, but I could always count on their response and clarifications.

Finally, for the benefit of those implementing systems, two "pearls" I've found on the Internet (I have no relation to them):

1. http://www.batteryservice.com, by far the best pricing for the AGM batteries I was looking for (unfortunately I found them too late in the process and could not arrange for a timely delivery)

2. http://www.vteworld.com/, a great selection of battery terminal covers (they sale retail through a subsidiary)

Alberto






On 6/1/2010 2:53 PM, acsarfkram wrote:
 


Hi Alberto

Those are some nice numbers, especially with the fouled bottom!

Are you using the PakTrakr amp meter or a separate meter?

Mark
Santa Cruz

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