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Amps draw per horsepower

P

Peter Hendra

Jan 1, 1970
0
Hi,
All this talk about circuit breakers has reminded me of something I
have been meaning to do.

I have a 1.5 horsepower 12 volt electric motor that powers my anchor
winch by a worm wheel.

Can anyone advise what the current draw is likely to be under load or
is this not enough information?

regards
Peter
 
P

Peter Hendra

Jan 1, 1970
0
1 HP = 746 Watts,
1.5 HP = 1119 Watts,
1119 Watts / 12 V = 93.25 Amps

If it has a fuse on it, I wouldn't be surprised if it were quite a bit
more (150A?) to allow for the starting load.

This is all theoretical, of course. Is there a fuse on it?

Jack

Hi Jack,
Thanks for this.
No, I'm stupid. There is no fuse. I never knew what size to put on it
and it was one of those things I always was going to do.
This has cost me. Last year when I soloed the Atlantic as my wife and
son were back in Australia for his schooling, I installed a switch
from the cockpit in addition to the foredeck up and down foot
switches. I also installed a relay at the winch end for the cockpit
switch. As I couldn't see the lay of the chain when hauling up I made
a "wanderlead" from switches and a cable I had on board at Arricefe in
the Canaries as I couldn't buy anything else locally. Worked well
except I neglected to turn the up switch off once and consequently
burnt out the windings. I now have waterproof push switches that will
prevent this.

All I know is that the winch is 1.5 HP from the brochure. It has been
a great winch for over 14 years requiring only a new set of brushes.
Made by Sindico in New Zealand - all bronze, it was half the price of
a Maxwell. It sold so well that Maxwell bought them out and shut them
down. Thus, I cannot get any information.

At the moment I am in the yard in Trinidad getting ready for the
Pacific. I bought a chain counter in Sydney and have to go through the
fun of drilling two holes in the bronze for the magnet and sensor.

The winch is powered by a Chinese starter motor - at least that is
what it looks like. Three connections, one for positive and two for
negative up and down. would 150 AMP be OK?

cheers and thanks
Peter
N.Z . yacht Herodotus
 
J

Jack Erbes

Jan 1, 1970
0
Peter said:
Hi,
All this talk about circuit breakers has reminded me of something I
have been meaning to do.

I have a 1.5 horsepower 12 volt electric motor that powers my anchor
winch by a worm wheel.

Can anyone advise what the current draw is likely to be under load or
is this not enough information?

1 HP = 746 Watts,
1.5 HP = 1119 Watts,
1119 Watts / 12 V = 93.25 Amps

If it has a fuse on it, I wouldn't be surprised if it were quite a bit
more (150A?) to allow for the starting load.

This is all theoretical, of course. Is there a fuse on it?

Jack
 
J

Jack Erbes

Jan 1, 1970
0
Peter said:
Hi Jack,
Thanks for this.
No, I'm stupid. There is no fuse. I never knew what size to put on it
and it was one of those things I always was going to do.
This has cost me. Last year when I soloed the Atlantic as my wife and
son were back in Australia for his schooling, I installed a switch
from the cockpit in addition to the foredeck up and down foot
switches. I also installed a relay at the winch end for the cockpit
switch. As I couldn't see the lay of the chain when hauling up I made
a "wanderlead" from switches and a cable I had on board at Arricefe in
the Canaries as I couldn't buy anything else locally. Worked well
except I neglected to turn the up switch off once and consequently
burnt out the windings. I now have waterproof push switches that will
prevent this.

All I know is that the winch is 1.5 HP from the brochure. It has been
a great winch for over 14 years requiring only a new set of brushes.
Made by Sindico in New Zealand - all bronze, it was half the price of
a Maxwell. It sold so well that Maxwell bought them out and shut them
down. Thus, I cannot get any information.
At the moment I am in the yard in Trinidad getting ready for the
Pacific. I bought a chain counter in Sydney and have to go through the
fun of drilling two holes in the bronze for the magnet and sensor.

The winch is powered by a Chinese starter motor - at least that is
what it looks like. Three connections, one for positive and two for
negative up and down. would 150 AMP be OK?

Your wife and kid were busy so you single handed across the Atlantic?
Sounds like you might not be the average sailor. My compliments sir!

Anyway, don't let me talk you into anything foolish. I am an idle
speculator and my experience with anchor windlasses is limited to having
used a few here and there.

Just as a matter of comparison, here is a manual for the Lewmar H2/H3
models. I realize it might not be a direct comparison but the numbers
seem similar to the ones we are bantering around here.

http://en.lewmar.com/support/PDF/windlass/H2-H3_manual.pdf

The H3 is sized for 12-15 meter boats and 5/16" or 3/8" chain. It is
rated at 1000 Watts, has a 860kg/12V and 970kg/24V maximum pull, and a
45kg working load. The manual calls for it to be fused at 85A on 12V
and 60A on 24V. So it looks like if yours is similar, starting with a
150A fuse might be a little too high.

I'd probably start with a 75A fuse and make sure the wiring was all
sized right for the run lengths. And I'd agonize over the cost of it
all and also have some 75A and 100A spares available.

If it blew a 75A fuse I'd like to try to immediately get my eyes and
hand on the motor housing to see how hot it had gotten before I went to
a 100A fuse.

Of course having things like clamp on Amp meters to watch with the motor
under load are wonderful for learning about the limits.

I learned the hard way once that a windlass that was properly sized for
lifting the ground tackle was not up to the sustained pull and run of
getting the boat up and over the anchor. Since then I've come to think
of them as something that you should lighten the load on as much as you can.

Good luck with that and the rest of your trip.

Jack
 
P

Peter Hendra

Jan 1, 1970
0
Your wife and kid were busy so you single handed across the Atlantic?
Sounds like you might not be the average sailor. My compliments sir!

Anyway, don't let me talk you into anything foolish. I am an idle
speculator and my experience with anchor windlasses is limited to having
used a few here and there.

Just as a matter of comparison, here is a manual for the Lewmar H2/H3
models. I realize it might not be a direct comparison but the numbers
seem similar to the ones we are bantering around here.

http://en.lewmar.com/support/PDF/windlass/H2-H3_manual.pdf

The H3 is sized for 12-15 meter boats and 5/16" or 3/8" chain. It is
rated at 1000 Watts, has a 860kg/12V and 970kg/24V maximum pull, and a
45kg working load. The manual calls for it to be fused at 85A on 12V
and 60A on 24V. So it looks like if yours is similar, starting with a
150A fuse might be a little too high.

I'd probably start with a 75A fuse and make sure the wiring was all
sized right for the run lengths. And I'd agonize over the cost of it
all and also have some 75A and 100A spares available.

If it blew a 75A fuse I'd like to try to immediately get my eyes and
hand on the motor housing to see how hot it had gotten before I went to
a 100A fuse.

Of course having things like clamp on Amp meters to watch with the motor
under load are wonderful for learning about the limits.

I learned the hard way once that a windlass that was properly sized for
lifting the ground tackle was not up to the sustained pull and run of
getting the boat up and over the anchor. Since then I've come to think
of them as something that you should lighten the load on as much as you can.

Good luck with that and the rest of your trip.

Jack

Hi Jack,
Thanks again for the information. I shall do as you suggest and work
up to progressively bigger fuses. This approach makes much sense and
actually makes me feel a little stupid for not thinking of it as my
role is a technical project manager(telecommunications) but sometimes
you can't see the wood for the trees.

As to the Atlantic crossing, thanks but I don't really deserve the
compliment as I really had no choice. As a family we had sailed to
Spain via the Red Sea from New Zealand. To be perfectly honest, apart
from bad head-on weather north of the Canaries where I lay for a day
to a sea anchor, the trip was probably the best long term sailing I
have ever done - days under genoa alone with the seas and wind on the
starboard quarter. The hardest part was to take a deep breath and get
started, as well as the loneliness and the lack of sleep. I made up a
digital counter attached to a piezo alarm that would go off after 20
minutes (or whatever I set - each count was one second) if I didn't
push the reset button. I did worry beforehand however that I might go
crazy from the isolation but after a while it became a spiritual,
peaceful journey that was rather sad to end once I ended up in
Barbados.

Incidentally, getting a parachute sea ancor back on board is a lot
harder by one's self as one simply cannot motor up to it whilst
another person pulls in the rode. In future I may not attach the trip
line and thus will not have to worry about fouling it with the prop.

cheers and again, many thanks

Peter
 
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