PaulRainbow
Well-known member
Usual garbage from this poster.
Fuses
- Thread starter KREW2
- Start date
PaulRainbow
Well-known member
If you expand post #11 you can read all of the text.
ChromeDome
Well-known member
No - the shared screendump is what It get from #11. But it doesn't matter, actually.
Sorry, GHB - won't share my privacy with Google and the rest of their realms.
And won't take part of a discussion on your level. Biased or not.
Sorry, GHB - won't share my privacy with Google and the rest of their realms.
And won't take part of a discussion on your level. Biased or not.
PaulRainbow
Well-known member
If you expand the second block of text you get:
"
ChatGPT
A thermal breaker fuse, also known as a thermal circuit breaker, is a type of safety device commonly used on sailing boats to protect electrical circuits from overloading and overheating.
The thermal breaker fuse works by interrupting the flow of current when the temperature of the circuit exceeds a certain threshold. This threshold is set by a bimetallic strip, which consists of two different metals bonded together. When the temperature of the strip reaches a critical point, the two metals expand at different rates, causing the strip to bend and trigger the breaker mechanism.
In sailing boats, thermal breaker fuses are often used in conjunction with other safety devices such as fuses and circuit breakers. They are particularly useful in high-current applications where traditional fuses may not be able to handle the load without blowing.
Overall, thermal breaker fuses play an important role in ensuring the safety and reliability of electrical systems on sailing boats, by providing an effective means of protection against overloading and overheating. "
KREW2
Well-known member
Thanks for all the sensible advice. especially Paul, and Alex
I have been out today and all was fine. However I will be taking Chrome Dome's advice and call the installer tomorrow and tell him I need him to check it out. I find it a little annoying not having full confidence in a system that I have just paid good money for.
I have been out today and all was fine. However I will be taking Chrome Dome's advice and call the installer tomorrow and tell him I need him to check it out. I find it a little annoying not having full confidence in a system that I have just paid good money for.
Alex_Blackwood
Well-known member
Good luck. Finding an intermittent fault is like searching for hens teeth, however it needs doing
KREW2
Well-known member
I forgot to mention, yesterday when I went out went it did not power up straight away. I thought it had blown the fuse again, but on inspection it was fine. I put it back in and it worked fine for the rest of the day. Just phoned the electrician and he is going to take the plotter away and get it checked out.
Thanks one and all
Thanks one and all
Alex_Blackwood
Well-known member
Question. Are you sure, absolutely sure, that the original 5amp fuse was blown? Perhaps just a bad connection on the fuse holder?? Even if the plotter checks out the circuit as a whole needs checking!
KREW2
Well-known member
Just got back from the boat and the plotter would not power up. Checked the fuse and it was blown again.
That's three fuses in two weeks. Of course I am not using it every day
That's three fuses in two weeks. Of course I am not using it every day
Pete7
Well-known member
A question for the electricians then. If the power supply wire was long and too thin, would this cause the fuse to blow when the chart plotter was in use?
Raymarine do have a habit of installing rather nice thick cables on their kit, might there be a reason for this?
Raymarine do have a habit of installing rather nice thick cables on their kit, might there be a reason for this?
noelex
Well-known member
Circuit breakers come in two equally popular designs.
Thermal circuit breakers:
This type of breaker uses a bimetallic strip to detect an overload. The excess current heats up the strip that breaks the circuit.
Magnetic/thermal circuit breakers:
In addition to the above mechanism, these breakers have a second type of trip mechanism. Excess current creates a strong magnetic field that trips the breaker. The advantage is that this mechanism can react very rapidly before overheating can occur. By using both mechanisms the circuit breaker will react quickly to gross overload (via the magnetic mechanism) and slowly to a moderate overload (via the thermal mechanism).
Both types of circuit breakers can be tailored to various trip characteristics.
Magnetic/thermal circuit breakers are generally superior (but more expensive) than purely thermal breakers, but both types can be used for many applications.
Thermal circuit breakers:
This type of breaker uses a bimetallic strip to detect an overload. The excess current heats up the strip that breaks the circuit.
Magnetic/thermal circuit breakers:
In addition to the above mechanism, these breakers have a second type of trip mechanism. Excess current creates a strong magnetic field that trips the breaker. The advantage is that this mechanism can react very rapidly before overheating can occur. By using both mechanisms the circuit breaker will react quickly to gross overload (via the magnetic mechanism) and slowly to a moderate overload (via the thermal mechanism).
Both types of circuit breakers can be tailored to various trip characteristics.
Magnetic/thermal circuit breakers are generally superior (but more expensive) than purely thermal breakers, but both types can be used for many applications.
noelex
Well-known member
Fuses are thermal devices. Anything that raises the temperature of the fuse such as thin wiring (relative to the current), a bad connection near the fuse, or even high ambient temperatures (such as a fuse installed in an engine bay) will cause the fuse to trip at a lower than normal level.
However, in practice fuses are generally (not always) designed to protect the wiring from a short circuit condition so there is generally considerable leeway. Nevertheless a poor connection in the fuse holder is a possibility for the frequent trips experienced in this case.
Alex_Blackwood
Well-known member
Further to that from Noelex. A long thin wire, very long thin wire, will cause a volt drop and resultant increase in current, this will be akin to an overload condition. This is a steady, higher % of full load current . If the load device is, for example a motor, it will struggle to start and trip the overload device. in a unit such as the OP's it is more likely that the display would not operate due to voltage limits. In this case the thermal breaker will trip. If for example the full load current of the device is 1 amp and the overload is 10% (1.1 amp) then it may trip in 10 minutes. if the overload is 20% it will trip in say 5 minutes. These figures are examples only. A fuse is designed to protect against Short circuit which is an instantaneous, infinitely high current which will blow the fuse instantaneously.
All very condensed and basic and I am afraid no help to the OP !
Alex_Blackwood
Well-known member
I must ask again. Are you 100% sure that the fuse has blown. Can you see evidence of this, if you use a meter do you get open circuit?? I have a sneaking suspicion that we are missing something. No criticism of the OP but in these on line discussions and diagnosis there is always the chance that the little bit of useful information that is not included is the most important. Bit like Hercule Poirot solving a case!
Alex_Blackwood
Well-known member
The fuse appears to blow either on switching off or switching on which would indicate a "Surge" type fault rather than a prolonged overload type. Depending on where in the circuit the fuse is fitted, if upstream of the CB then the fault could be anywhere from the fuse holder to the unit. If downstream of the CB then the fault must be from the fuse holder to the unit. If the fault is downstream if the CB then I would expect that to trip first.
I would still like absolute confirmation from the OP that the fuse has actually blown and that he isn't temporarily clearing a fault by replacing one with another.
KREW2
Well-known member
Thanks one and all. I had no intention of doing any testing or work myself, apart from replacing blown fuses. I wanted advice in case I was fobbed off by the installer.
However that is not going to be the case, they have just phoned me to say Raymarine have agreed the unit must be at fault, and they are going to replace it with a new one.
However that is not going to be the case, they have just phoned me to say Raymarine have agreed the unit must be at fault, and they are going to replace it with a new one.
Alex_Blackwood
Well-known member
Don't forget the update
ChromeDome
Well-known member
Nice
Baggywrinkle
Well-known member
The element 9 connects to the NMEA bus .... do you have any NMEA devices connected as they may be blowing the fuse rather than the plotter itself.
Element 9 wiring from Raymarine Manual ... red arrow is NMEA Bus - it should have its own separate power supply I do hope it is not drawing power from the plotter.
Element 9 wiring from Raymarine Manual ... red arrow is NMEA Bus - it should have its own separate power supply I do hope it is not drawing power from the plotter.
KREW2
Well-known member
I have to take the electrician on face value, and hope he knows what he is doing, or done. I know he has put three new inline fuses into the system. One five amp to the plotter. The others are 7.5amp and 10 amp.
I wont, as I still find it odd. They haven't been down to the boat to check it out, so I was surprised when after only 24 hours of me phoning them Raymarine have just conceded it is the plotter without any checking being done.