Sounds like what he was describing is a slow-blow circuit breaker. There
are basically 3 things to keep in mind on breakers. One is how much inrush
current they can withstand (a high, but short duration, peak). The other is
the rating (that's what is printed on breaker, e.g. 150A). Another is the
duration of excess current, e.g. slow blow, normal, fast blow. The duration
spec is usually listed as a 'profile'. "G" is normal, "H" is slow blow,
etcetera. Motors often use high-inrush slow blow breakers, but often use
high-inrush and normal blow breakers. That's fine, if the motor maker
recommends it. Remember, a circuit breaker is not designed to prevent
excess current ...it's designed to prevent fire. Motors can take excess
current to a point, then the windings catch on fire. Always go with the mfg
recommendation and double check the factors I listed with them. Next,
assuming your motor is able to take 250A and you use a 150A slow blow
breaker, note that you'll cause a wiring fire if you don't size your wiring
for 250A instead of the 150A. When you buy your 150A breaker, you need to
double check the breaker specs to make sure it is OK to put the large gauge
wire in it. The contacts and mechanical clamping must be designed for the
higher gauge wire. On high current wiring, ALWAYS use saddle-clamp type
breakers (and terminal blocks in the rest of the wiring). Saddle-clamp
breakers clamp the wire by pressing a metal plate against the conductor
rather than turning a screw into the conductor. The cheap ones that turn a
screw into the conductor risk cutting into the wire and for multi-strand
wire, strands can be cut off. This reduces the current carrying capacity of
the wire, right at the breaker. A hot spot...another fire hazard. If you
*must* use a breaker that has a screw turning directly onto the wire, then
clamp a ferrule (go to Platt or other) onto it before inserting it into the
breaker. A ferrule is nothing but a metal tube, usually with a plastic
sleeve on one end to insulate exposed wire, that you crimp onto the wire
(use the right crimping tool.) Never put the lesser of 2 conductors or what
the circuit breaker (or terminal block) manufacturer recommends into the
contact on the breaker. Breakers are sometimes listed as 1-conductor
breakers when they are high-current types. Note that some breakers are
rated for DC, and some for AC, and some for AC/DC. All can be used for DC,
but the DC cannot be used for AC ...they have polarity, which means they are
designed for current flow in one direction only (double check with mfg specs
on AC breakers for use on DC, but I've not seen an exception to the rule I
stated.) Finally, my own preference is to look for breakers that are UL
listed (better than 'UL Recommended' which means they have constraints on
their use that you'll probably never know) *and* CE listed. That makes them
world-wide compatible and the tighter of anybody's requirements will have
been built into them.

Brian

--
My boat project: http://www.advantagecomposites.com/tongass


"Steve" wrote in message
...
When I was working out the electrical supply for my Lewmar 1000 Vert.
anchor
windlass, I noted that the Max current @ max load (stall) was 250 amps.
while the recommended circuit breaker/slowblow fuse was suppose to be only
150 amps.

In my mind, this ment that the breaker would trip before I could stall the
windlass. Something that is done every time I have an anchor set into
mud..
I couldn't imagine that these numbers were correct.

At the time I was purchasing my breakers from Waytec Inc.. When I
presented
my concern to them, they admited they didn't know the answer but referred
me
to the engineer at Bussman (or something like that) that make most all
automotive fuses and breakers. (They also were the original manufactures
of
the breakers that Blue Seas now sells. )

Here is what he explained (as best as I can remember and understood). If I
go with the Lewmar recommended breaker size of 150 amps, I can pull to the
maximum working load and stall the windlass for about 30 to 40 seconds
before the 150 amp breaker will trip..

This makes sense to me in my windlass application because the normal
hauling
load to take up the chain slack will be well below the 1000 lb capacity..
(total chain/anchor weight in the water will only be around 500 lb.).
When
I break the anchor out, I haul the chain up short, until the windlass
stalls, then let the bouyancy of the bow and any swell, actually break the
anchor out. If it's really set, I use the engine to run over the anchor
and
break it out that way. The amount of time I might ( an extreme case) have
full load on the windlass motor would never be more than 15-20 seconds.
Well
within the trip spec of the 150 amp circuit breaker.

Glenns situation will be similar. Since his winch is for halyards, the
winch load will be low until he 'sweats' the halyard after the sail is
fully
hoisted. This shouldn't be more than a few seconds. I think it would be
smart to have a breaker under the load rating of the winch, since the
operator can't 'feel' when he has a halyard jammed/fouled. Could prevent
some serious damage aloft.

Too conclude my circuit breaker tail; Once I was satified with the Bussman
engineer (very nice guy ) assistance an explaination, I order one breaker
from Waytec to use to template my electrical panels openings and fabricate
buss bars. In the final layout I ended up making openings for a total 4 of
these Bussman panel mount breakers of differing amp ratings..

Eventually I placed an order for the remaining 3 breakers, now knowing
what
amp size I wanted.

So Sorry! Bussman has discontinued all of these type of circuit breakers.
;o(

Before I scrapped my exist panels and buss bars, I happened to notice that
West Marine was selling the same breakers under their name but for about
$40. I found Blue Seas name and phone number on the packaging and
contacted
them.. They told me they also sold their products through Fisheries Supply
in Seattle.. Since I had a wholesale account with them I ended up getting
the exact same breakers as I had built my panels for, for $24 each.


--
My opinion and experience. FWIW

Steve
s/v Good Intentions