Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.


MikeAqua

6059 posts

Uber Geek


#276004 21-Sep-2020 11:50
Send private message quote this post

I need a slow blow 20A fuse as part of an install I'm doing at the moment.  It's for a BEP Surge Protection Module https://www.bepmarine.com/en/80-707-0004-00 

 

I'm struggling to find a fuse and matching surface mount holder.  Many of the holders seem to be PCB mount.

 

Surface mounted because it will be installed on a DC distribution panel.  The purpose of the fuse as I understand it is to convert excess energy into heat.  Therefore, I've it would get hot and I've ruled out enclosed holders.

 

Ideally I'd like a single fuse holder.





Mike


Create new topic
elpenguino
1482 posts

Uber Geek

Subscriber

  #2569130 21-Sep-2020 12:05
Send private message quote this post

https://nz.element14.com/w/c/circuit-protection/fuses-fuse-accessories/fuse-holders/prl/results?st=panel%20mount%20fuse%20holder

 

 

 

There's over 100 to choose from.

 

Yes, the job of the fuse is to convert electricity into heat, but only once.

 

BTW: The user manual doesn't show a fuse in use. https://www.bepmarine.com/en/~/media/inriver/350782-34855.pdf

 

 


richms
23681 posts

Uber Geek

Trusted
Subscriber

  #2569274 21-Sep-2020 13:22
Send private message quote this post

A fuse running near its breaking capacity will put out considerable heat, since they are there to protect the wiring they shouldn't be near their limit very often, but 18A thru an automotive 20A blade type fuse all day will quickly make the holder go crispy.





Richard rich.ms

 
 
 
 


MikeAqua

6059 posts

Uber Geek


  #2569342 21-Sep-2020 14:27
Send private message quote this post

elpenguino: BTW: The user manual doesn't show a fuse in use. https://www.bepmarine.com/en/~/media/inriver/350782-34855.pdf


 



It’s definitely in the installation instructions.




Mike


elpenguino
1482 posts

Uber Geek

Subscriber

  #2569346 21-Sep-2020 14:37
Send private message quote this post

MikeAqua:
elpenguino: BTW: The user manual doesn't show a fuse in use. https://www.bepmarine.com/en/~/media/inriver/350782-34855.pdf

 

 

 



It’s definitely in the installation instructions.

 

I see that in the instructions but not in that summary I linked to. Does this module have an indicator to show it is connected. You want to be sure you are aware of when the device has blown the fuse and no protection is then provided.

 

The fuse should not be carrying much current in normal circumstances, assuming the system voltage is not regularly higher than 17v.


SomeoneSomewhere
277 posts

Ultimate Geek

Lifetime subscriber

  #2571589 21-Sep-2020 23:06
Send private message quote this post

A 20A MCB is also an option. Mains rated ones are generally also rated for around 48-72VDC at the same fault current, at least for the DIN rail mount versions. I'm not sure about the plug-in ones.


MikeAqua

6059 posts

Uber Geek


  #2571780 22-Sep-2020 09:27
Send private message quote this post

elpenguino:

 

Does this module have an indicator to show it is connected. You want to be sure you are aware of when the device has blown the fuse and no protection is then provided.

 

The fuse should not be carrying much current in normal circumstances, assuming the system voltage is not regularly higher than 17v.

 

 

Under normal operating circumstances, system voltage won't exceed 13.7v. Any spikes above that will be transitory, likely caused by a motor (starter or capstan) fault.  

 

If 17v voltage is exceeded the module closes a latching relay, which stays on until the module is power cycled. The relay outputs will be connected to a flashing warning LED on the dash.

 

All the electronics on the boat are rated up to 24v.

 

 





Mike


elpenguino
1482 posts

Uber Geek

Subscriber

  #2571784 22-Sep-2020 09:30
Send private message quote this post

Yes, I got that. But the unit also discharges brief transients without latching. 

 

What I'm getting at is that if the unit never latches and flashes the LED via the relay does that mean it is not detecting any transients? Or does it mean the fuse is blown?

 

You need another LED across the supply after the fuse labelled 'when indicator not lit, fuse is blown'.


 
 
 
 


MikeAqua

6059 posts

Uber Geek


  #2571795 22-Sep-2020 09:39
Send private message quote this post

SomeoneSomewhere:

 

A 20A MCB is also an option. Mains rated ones are generally also rated for around 48-72VDC at the same fault current, at least for the DIN rail mount versions. I'm not sure about the plug-in ones.

 

 

If I can use an MCB, that would be great as I have an 3 x MCB housing in the same range (contour lock) as the Surge Protection Module and adjacent master switch.  They would all clip together very tidily.  

 

But ... do MCBs replicate the slow blow of the fuse?

 

I'm guessing the SPM stores excess energy in some way (?capacitor?), and then slowly releases it to the fuse, to be dissipated as heat.  I'm concerned that an MCB that immediately tripped, wouldn't dissipate much energy before it tripped.

 

This is mostly guesswork on my part (I'm a biologist by trade) so please correct me if I am wrong.

 

 

 

 





Mike


SomeoneSomewhere
277 posts

Ultimate Geek

Lifetime subscriber

  #2571803 22-Sep-2020 09:54
Send private message quote this post

The energy is dissipated in the SPM itself. If it's anything like AC mains versions, the fuse is only there to disconnect the SPM if it fails (as they tend to fail to a short circuit condition). No energy is intentionally dissipated in the fuse.

 

The reason for a slow-blow fuse is so that it doesn't immediately blow when the SPM draws huge amounts of current to clamp the voltage.

 

You would ideally use a D-curve breaker as these are equivalent to a slow-blow fuse.


MikeAqua

6059 posts

Uber Geek


  #2571805 22-Sep-2020 09:54
Send private message quote this post

elpenguino:

 

Yes, I got that. But the unit also discharges brief transients without latching. 

 

What I'm getting at is that if the unit never latches and flashes the LED via the relay does that mean it is not detecting any transients? Or does it mean the fuse is blown?

 

You need another LED across the supply after the fuse labelled 'when indicator not lit, fuse is blown'.

 

 

I could use the fuse circuit to control an NC relay which powers an LED. If the fuse blows the relay closes and the LED comes on.





Mike


MikeAqua

6059 posts

Uber Geek


  #2571861 22-Sep-2020 10:53
Send private message quote this post

SomeoneSomewhere:

 

You would ideally use a D-curve breaker as these are equivalent to a slow-blow fuse.

 

 

After some research the MCBs have quite a slow trip profile.  They are Airpax IAG units and meet their D66 delay profile which is designed for motors.

 

These are the curves

 

 

 

 

 

 





Mike


Create new topic





News »

Huawei launches IdeaHub Pro in New Zealand
Posted 27-Oct-2020 16:41


Southland-based IT specialist providing virtual services worldwide
Posted 27-Oct-2020 15:55


NASA discovers water on sunlit surface of Moon
Posted 27-Oct-2020 08:30


Huawei introduces new features to Petal Search, Maps and Docs
Posted 26-Oct-2020 18:05


Nokia selected by NASA to build first ever cellular network on the Moon
Posted 21-Oct-2020 08:34


Nanoleaf enhances lighting line with launch of Triangles and Mini Triangles
Posted 17-Oct-2020 20:18


Synology unveils DS16211+
Posted 17-Oct-2020 20:12


Ingram Micro introduces FootfallCam to New Zealand channel
Posted 17-Oct-2020 20:06


Dropbox adopts Virtual First working policy
Posted 17-Oct-2020 19:47


OPPO announces Reno4 Series 5G line-up in NZ
Posted 16-Oct-2020 08:52


Microsoft Highway to a Hundred expands to Asia Pacific
Posted 14-Oct-2020 09:34


Spark turns on 5G in Auckland
Posted 14-Oct-2020 09:29


AMD Launches AMD Ryzen 5000 Series Desktop Processors
Posted 9-Oct-2020 10:13


Teletrac Navman launches integrated multi-camera solution for transport and logistics industry
Posted 8-Oct-2020 10:57


Farmside hits 10,000 RBI customers
Posted 7-Oct-2020 15:32









Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.


Support Geekzone »

Our community of supporters help make Geekzone possible. Click the button below to join them.

Support Geezone on PressPatron



Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.