T-Pain Is On A Boat: Re: [Electric Boats] Re: does anyone have current real world performance figures please

Monday, April 8, 2013

Re: [Electric Boats] Re: does anyone have current real world performance figures please

Julian,

Nice rant.

As a HVAC Engineer,aka air conditioner repairman, I am neither an electrical engineer nor an electrician even though I have to work with all manner of electical things on a daily basis. And as an old school guy I'm border line developmentally disabled when it comes to matters of electronics and anything to do with programming. When I was in school we were loading Fortran cards into a big machine. But I would like to comment on a similar scenerio in the HVAC industry with your rant about electric propulsion.

According to manufacturer's data,0.5% of air conditioner compressor failures are a result of a "manufacturer's defect" in material or workmanship although failure rates for compressors are typically in the 5-15% or greater range, dependiing on the contractor. This means that the vast majority of compressor failures are caused by technician errors in installation. So the next time you want to cuss Carrier, Trane, or any of the major manufacturers, take a closer look at the guy who installed it. That's probably where the problem is.

Carter

From: Julian Webb <julian.proto@gmail.com>
To: electricboats@yahoogroups.com
Sent: Monday, April 8, 2013 10:50 AM
Subject: Re: [Electric Boats] Re: does anyone have current real world performance figures please

Hi Kevin

- As failures "always" happen on a Friday night at 11:00 p.m. in the only area that doesn't have an agent for the piece of gear that's just gone "pop", I was determined to talk to anybody I could find who'd had failures with electric drives and who were willing to put up with me long enough for me to find out what had actually failed.

- Once I took out:

1) The "happy hopefuls" who had stitched a system together based on what they could afford rather than based on what they really needed,

2) Those who had no technical knowledge and were taken advantage of by a slick salesman only too happy to finally sell that stock he's been sitting on for 2 years, albeit mismatched and unsuited to their needs,

3) The system put together by someone who chose each component on it's specifications but without thought to, experience of or knowledge of how they would work when all wired together into a system.

and finally the one that had turned a lot of potential converts off and had me personally most concerned:

4) The system put together by those who did know what they were doing, electrical engineers, industrial electricians and even electrical equipment manufacturers, that just kept having "mystery" failures that were so frustrating and unfathomable that even the most patient boat owner just eventually ripped it all out and figured the $10K he had just thrown in the bin was nothing compared to the dream of quiet low maintenance retirement, now ruined

- there were actually very few genuine failures.

- Electrical work looks so easy most anyone can do it, so most everyone does, especially low voltage, so to someone who has a successful history as "being handy with things" it can't be that hard, right.

- Good work practice isn't sold with the equipment and many simply don't appreciate the importance of;

cable sizing, length of runs etc (too small cable size by even one size down causes the voltage to drop which usually sees the current rise, shortening the life of connections, motors, controllers etc)
good connections (bad ones generate heat and arcing and ones open to wetting by sea water (even vapour) will see the cable corrode where it joins the connector)
heat buildup (every lousy 10 degrees C a motors windings run above it's rating can halve it's life)
open frame motors in a boat or any environment where high humidity is guaranteed is asking for trouble I think, and in my and others experience no amount of "tropicalising", "marinising" or vacuum impregnating of windings seems to save those installed where they are subject to high salt air humidity.
feeling proud of a nice neat and tidy installation might give a sense of pride but again many don't know what temperature or humidity their lovely new gear is going to reach once they shut the door/cover/hatch and go toast a job well done.

- Sorry to sound negative but most wouldn't dream of monitoring temperatures with equipment running as it normally would, shut in and forgotten, and can't understand why a motor gives up the ghost after 6 months, or a circuit breaker starts to trip all too often and there's nothing obviously wrong.

- In the dozens of failed installations I checked, 9 times out of 10 it was either the installation environment the gear was operating in, a bad choice of or unsuitable equipment, or a mismatching of system components that caused the "damn thing to fail, and it's only been in for 5 months, last time I ever buy anything made by G.E.".

- You can check things out all you like on the net and talk to as many sparkys as you like, but I've sat behind an engineer from Siemens (not picking on them, at least they turned up to try to work out what was causing the problem) who had to use an oscilloscope inserted between the right two pieces of gear to finally identify the reason a commercial craft had had repetitive failures. The drama was they had nothing in their arsenal that could do the job, and the rule-of-thumb in such situations of doubling the size of the alternator simply couldn't be accommodated......... all pulled out and back to Diesels!

- I've raved on enough but genuine equipment failure is rare, it's nearly always