Electrical Guestimates

[Stu Jackson]

Thanks for that. Kinda deals with the thread drift...

Would be nice to hear from the OP...

[skipmac]

Originally Posted by Cap Erict3

Once, after I had grilled the individual responsible for making us comfortable with a new PM program in my prosecutorial style, a co-worker and dear friend turned to me and asked if I had any idea how crass I had just been. (I paraphrase here. There were curse words in his description of my actions)

Thanks Skipmac.

PM??

personal motivation
professional management
peer management
part-time mothering

I thought of a few more but don't want to get banned from the forum. Same with synonyms for crass that occurred to me.

[skipmac]

Originally Posted by Stu Jackson

Thanks for that. Kinda deals with the thread drift...

Would be nice to hear from the OP...

Thread drift. What thread drift?

[skipmac]

Originally Posted by Cap Erict3

My apologies for responding in a less than patient manner.

And hopefully my reply came across as a sincere request for comment if maybe just slightly tongue in cheek.

I don't have extensive experience specifically with motors but I do have a BSEE and even though the focus was digital circuit design and IC fabrication I did come out of it with some basic knowledge of 12V DC and a vague understanding of motors.

Based on this and a few years of messing about in boats here's my understanding.

Motors (of any kind, not just DC) do not like to run on low voltage. Causes them to draw more amps to generate the same output, run hotter and shortens the life.

12V DC is very susceptible to voltage drop, especially high amps over long runs.

So using the example given by hellosailor what size cable would you recommend? Do you disagree with the data on voltage drop he used? Do you disagree with the effect of the voltage drop on the windlass?

[hellosailor]

And I'd add that at least one brand name windlass, sold for "30 to 40 foot" boats, is rated to draw 80 AMPS NOT 40 at 12VDC.

Perhaps it does only draw 40, I haven't measured any. But given the rating for 80, that puts the need for wastefully oversized [sic] cables in a whole other range, doesn't it? Which anyone else can run.

Lewmar H2 Gypsy / Drum Horizontal Windlass Kit

• 8 mm Gypsy / Drum, Power: 12 Volt DC, Watts: 700, Draw: 80 Amps
• Chain: 5/16" G4 or BBB, Line: 9/16 3 Strand, 8 Plait, 5/8" 8 Plait
• Finish: White Powder Coating, Maximum Pull: 1433 lbs, Boat Length: 30' to 40'

[Cheechako]

I believe my Maxwell 2500 V came with a 150 amp dedicated breaker.

[Cap Erict3]

In many years I have never gone wrong using the 125% over rated current standard.

In the world of commutator based dc motors you have series, shunt and compound wound motors. Normally a series motor would be used in an anchor winch due to potential high starting torque. A permanent magnet motor is also common in a lower cost unit.



http://en.wikipedia.org/wiki/Brushed...es_wound_motor


Btw the "PM" was "preventive maintenance."

[Lake-Effect]

Originally Posted by Greenhand

The survey came up with a handful of electrical issues. ...

We need to:
-rewire the windlass: it was done by taping the DC wires to the windlass wires, no breaker anywhere, no stud. And the wires have pulled out of their tape.
-rewire the AC to the battery charger - they didn't use marine grade and it is showing signs of wear
-diagnose a bilge pump
-terminate the wires that used to run to the air conditioning - evidently they are just kind of hanging there.

and, I am not sure if this is for an electrician or a mechanic, but the alarm system on the engine is not functioning

Is this all the surveyor flagged? were there any negative comments about the DC or AC panels?

If the surveyor knows their stuff, and that's the only electrical things they expressed concern about... that's pretty good news, I'd say.

Everything on your list - I'd estimate $1k at most*, if a pro can knock them off in a couple of days. Less if they have their sh!t together and arrive with all the right stuff on their truck.

(* assuming the engine alarm is an easy fix. A new engine panel is $$)

[hellosailor]

"Maxwell 2500 V " specifies the windlass as drawing 100 Amps, even bigger still. If they're expecting 100A service, a 150A breaker isn't unreasonable.

Of course with any of them, how much it actually draws will depend on what you're pulling.