Thermal Circuit Breaker for Anchor Windlass

[CJ13]

I need a Thermal Circuit Breaker for a new Anchor Windlass.
Blue Sea 187 series look suitable, but the data states ' not to be used with high inrush currents'. I'm not sure what this means - are they suitable for my application?

Thanks,
John

 

[Sandyman]

The initial starting current of a DC motor is typically about 8 times the running current and I would assume that is what they mean by ''inrush current''. Strange term. If that is the case then no they are not suitable.

 

[Lon nan Gruagach]

The initial starting current of a DC motor is typically about 8 times the running current and I would assume that is what they mean by ''inrush current''. Strange term. If that is the case then no they are not suitable.

A common term in my vocabulary, just generic extra switch on demand in any circuit whether its warming up an incandescent lamp or charging capacitors. In the specific case of motors you might call it starting current. But, if you are going to be that picky then stalled current is more appropriate.

 

[Adamastor]

The response curve the manufacturers specify is a "slow burn" type. Normal CB behaviour is to knock off early as soon as designed load is reached. Slow Burn types hold out for slightly longer- typically 10 sec to cope with inrush current. I'm afraid I can't remember the curve shape but the types of CB do vary, and the wrong one will try your patience when you use your windlass in anger!

 

[PaulRainbow]

I need a Thermal Circuit Breaker for a new Anchor Windlass.
Blue Sea 187 series look suitable, but the data states ' not to be used with high inrush currents'. I'm not sure what this means - are they suitable for my application?

Thanks,
John

That's not what it says.

It says " Do not use as a switch where high inrush currents are expected."

You won't be using it as a switch, as such, so it will be fine.

 

[pmagowan]

That's not what it says.

It says " Do not use as a switch where high inrush currents are expected."

You won't be using it as a switch, as such, so it will be fine.

Is that not exactly what he will be using it as?

 

[PaulRainbow]

Is that not exactly what he will be using it as?

No. He'll be using it for circuit protection.

If he does use it as a switch (to isolate the circuit to the windlass) he won't be doing it under load so there won't be an in ruch current.

 

[captainboo]

Is that not exactly what he will be using it as?

No because he will close the cb as the safety/isolator then be using the windlass control switch to operate the windlass. The only time it will operate as a switch will be opening as a cb due to overload as it is designed to.

 

[pmagowan]

No because he will close the cb as the safety/isolator then be using the windlass control switch to operate the windlass. The only time it will operate as a switch will be opening as a cb due to overload as it is designed to.

Yes. Not sure I understand why it is not a switch when it will be used as a switch to turn things off as overload protection as it is designed. What function does it have that is not a switch? Perhaps it is just my ignorance of what the word 'switch' means in electronics.

 

[PaulRainbow]

Yes. Not sure I understand why it is not a switch when it will be used as a switch to turn things off as overload protection as it is designed. What function does it have that is not a switch? Perhaps it is just my ignorance of what the word 'switch' means in electronics.

Circuit protection isn't classes as being a switch. That's the circuit breaker function of this device. In addition to being a circuit breaker this one is a switch. The lever that trips when it acts as a circuit breaker can be manually used as an isolator switch.

The Blue Sea statement about "current in rush" refers to using the device as a switch, in the sense of an isolator switch, when the appliance connected to it is under load. If the appliance was turned on when you switched the circuit breaker "on", you could get a current in rush. This obviously won't apply to the OP, even if he uses it as an isolator switch he won't do so with the windlass running.

 

[pmagowan]

Got you. My simple brain just considers anything that breaks a circuit and remakes it as a switch. I didn't know that a circuit breaker was specifically not classed as a switch in this context.

 

[Mistroma]

The original breaker for my windlass went several years ago. It only lasted a couple of years from new but had a tendency to trip sometimes when starting to pull the chain. When I dismantled it there was evidence of arcing internally and that's what finished it off eventually. I could see that it was designed to dissipate any arcing on disconnect but assumed it had simply tripped once too often and the damage had simply built up over time.

The replacement ETA breaker was quite expensive and I knew that it was likely to suffer the same fate anyway. I looked at a lot of technical specs. and decided on a Carling model. I think it was a C series but would need to check. It had the same trip current as the ETA but very different delay characteristics. I seem to remember that the ETA would trip after a few seconds at the startup current I expected and the Carling was much longer (might have been quoted as 10-60 seconds at 2x trip value).

The Carling unit is rated correctly for my windlass and has worked perfectly since fitting. I don't get spurious startup trips now so well worth digging into the manufacturer's specs. before buying. As a bonus, it was about 1/3 the price of the original ETA model.

I'm certain that Jeanneau didn't choose the best breaker for the job.

I have a vague memory of buying from a company called Acorn Engineering and found an old link to http://www.acornengineer.co.uk

 

[CJ13]

Thanks everyone- that's really useful information.
The Blue Sea 100A Circuit breaker is about 1/3 the price of the Lofrans CB, so looks a good option.

John