Circuit Breaker for Anchor Windlass

[CJ13]

I'd like to replace the existing 70amp block fuse to my windlass with with a circuit breaker. There seem to be 2 types of CB-
1. Thermal CB's which are push button re-set.
2. Magnetic CB's with a lever that switches up/down.

Would either type be suitable?

Thanks,
John

 

[omega2]

No. 1 just cut the main + and connect each side to make the circuit. If the motor starts to struggle it will break. 70 amps may be expensive.

 

[Talulah]

We have the latter. Option 2.

 

[Elemental]

We have the latter. Option 2.

+1

 

[Retired in Crete]

Just bought No 1, 100 amp for 85 Euros (Approx 68 GBP) mail order from Athens.

If it is hot, as often it is here it will "break" at a lower amperage.

John

 

[CJ13]

We're in Minorca heading eventually for Greece/ Turkey, so it'll be hot for us, so i guess i really need an Magnetic CB.
The problem is i've only found a Thermal CB at a reasonable price.

 

[Retired in Crete]

On the instructions with mine there is a graph showing the break point/temp. It is on the boat at the moment but from memory it will break at 80 amps at 40 C.

I have mounted it below deck so, hopefully it will stay a bit cooler.

John

 

[Graham_Wright]

Heidenhein/Eaton/Re-Cirk-It all make lever breakers. I have bought them on eBay for a song. I also bought a box full ~ 50 for £50 at Beaulieu.

Whatever you buy, make sure it is for DC. You can parallel them by linking the toggles. All the toggles on mine are drilled for such a link. It makes "fine tuning" a doddle.

 

[VicMallows]

You can parallel them by linking the toggles.

It sounds rather hopeful to me to parallel breakers to accurately achieve a higher current rating. I would certainly want to test such an arrangement fully in situ to determine a consistently repeatable trip point, and that would need suitable equipment. The mechanical linking facility is intended for creating multi-pole trips where an overload on any one pole/phase trips all.

 

[Graham_Wright]

It sounds rather hopeful to me to parallel breakers to accurately achieve a higher current rating. I would certainly want to test such an arrangement fully in situ to determine a consistently repeatable trip point, and that would need suitable equipment. The mechanical linking facility is intended for creating multi-pole trips where an overload on any one pole/phase trips all.

Point taken but we are not looking for ultra precision here. If the breakers are each 50A say, a normal load maximum of 90A and a "what the hell's got hold of the anchor" overload of 150A, I think he should be safe!

 

[cimo]

I'd like to replace the existing 70amp block fuse to my windlass with with a circuit breaker. There seem to be 2 types of CB-
1. Thermal CB's which are push button re-set.
2. Magnetic CB's with a lever that switches up/down.

Would either type be suitable?

Thanks,
John

hi John
thermal CBs tend to have poor precision (temperature dependent bi-metal strip) and are relatively slow to operate.

magnetic CBs are much faster and have an excellent low overload response (which can be a disadvantage causing nuisance tripping).

there is a third type - thermal-magnetic CBs - which combine the best features of both, i.e. fast acting with slow low overload tripping.

for what its worth................
Your 70A block fuse was rated based on its response time?, and may no longer apply now that you're going over to a CB.
If possible, check your windlass specifications for operating current & short circuit current specifications. your CB rating should be chosen to lie somewhere in between. I'd spec a thermal-magnetic CB near to the operating current. or a magnetic CB further towards the higher figure. The CB trip curve will show the likely response times as a function of multiples of the CB rated trip current. (Radionics do reasonable priced DC magnetic CBs, you can usually view the trip curve data online before you buy).

 

[philip_stevens]

I'd like to replace the existing 70amp block fuse to my windlass with with a circuit breaker. There seem to be 2 types of CB-
1. Thermal CB's which are push button re-set.
2. Magnetic CB's with a lever that switches up/down.

Would either type be suitable?

Thanks,
John

This is the type I have fitted with my Quick windlass. It is an "Hydraulic magnetic circuit breaker".

 

[nigelmercier]

Your 70A block fuse was rated based on its response time?, and may no longer apply now that you're going over to a CB...

I'd say, will no longer apply...