• Welcome to DOSBODS

    Please consider creating a free account to be able to access all the features of the DOSBODS community. It only takes 20 seconds!

Sign in to follow this  
SNACR

Any electrical experts?

Recommended Posts

The following fuses have blown in a three-phase charger I'm attempting to repair. They're marked 690v but are much pricier than 500v for some reason. They are on the input side so the voltage shouldn't exceed 500v but there are hefty solenoids and transformers so is there some back emf type thing or something I'm missing?

690v

http://uk.rs-online.com/web/p/cartridge-fuses/8068405/

500v

http://uk.rs-online.com/web/p/cartridge-fuses/2303474/

 

 

 

Share this post


Link to post
Share on other sites

I'm not a power electronics expert, just a hobbyist but ... it looks like expensive ones are the super fast blow ones designed for inductive loads:

Type gG fuses (also known as gL-gG) are for general purpose resistive loads
Type aM fuses are for inductive loads e.g. motors

Share this post


Link to post
Share on other sites
18 minutes ago, goldbug9999 said:

I'm not a power electronics expert, just a hobbyist but ... it looks like expensive ones are the super fast blow ones designed for inductive loads:

Type gG fuses (also known as gL-gG) are for general purpose resistive loads
Type aM fuses are for inductive loads e.g. motors

I might just have picked the wrong link I think the 500v ones I was looking at on ebay were ultra-rapid blow also - I'm hoping this has saved the very expensive charger as apparently there were a couple of loud bangs when it was connected and it went dead which was hopefully just the fuses, although this doesn't explain why they did go as doesn't seem to have been a power surge. They probably will need to be ultra-quick blow because like a lot of the 3 phase stuff with big motors or transformers they draw a big amount on start up only for it to level out so have to have slow acting (type D) breakers, which I don't like given the added danger of 3 phase voltage already.

Share this post


Link to post
Share on other sites
5 minutes ago, MrPin said:

690 volts is generally used on ships. Where is your next port of call?

I've wasted half an hour reading about how a paper mill in Norway moved over to 690v motors and improved efficiency but it's not got me any further with this charger.

Share this post


Link to post
Share on other sites
39 minutes ago, Long time lurking said:

Fork lift charger shop ?

Good guess but it's for a BM74000 load simulator - although it is the same as a forklift charger unfortunately I don't have another one suitable in my vast hoard of redundant ones - which I regret not disposing of a lot of them when copper scrap value was higher.

BM-Autoteknik-BM74000-Commercial-Vehicle

Edited by SNACR

Share this post


Link to post
Share on other sites
1 hour ago, SNACR said:

Good guess but it's for a BM74000 load simulator - although it is the same as a forklift charger unfortunately I don't have another one suitable in my vast hoard of redundant ones - which I regret not disposing of a lot of them when copper scrap value was higher.

BM-Autoteknik-BM74000-Commercial-Vehicle

Regret no more, copper is currently spot $3/lb. 

Share this post


Link to post
Share on other sites
3 hours ago, SNACR said:

Good guess but it's for a BM74000 load simulator - although it is the same as a forklift charger unfortunately I don't have another one suitable in my vast hoard of redundant ones - which I regret not disposing of a lot of them when copper scrap value was higher.

BM-Autoteknik-BM74000-Commercial-Vehicle

I don't know what it is for, but I want one.:o

Share this post


Link to post
Share on other sites
5 hours ago, SNACR said:

The following fuses have blown in a three-phase charger I'm attempting to repair. They're marked 690v but are much pricier than 500v for some reason. They are on the input side so the voltage shouldn't exceed 500v but there are hefty solenoids and transformers so is there some back emf type thing or something I'm missing?

690v

http://uk.rs-online.com/web/p/cartridge-fuses/8068405/

500v

http://uk.rs-online.com/web/p/cartridge-fuses/2303474/

 

 

 

 

IMG_3818.PNG

Share this post


Link to post
Share on other sites
8 minutes ago, MrPin said:

I don't know what it is for, but I want one.:o

Truck brake testing - they were developed at vast cost specifically for the Department of Transport, in this country, who then promptly closed all their MOT centres. Unfortunately you can't trundle them round like a giant ten ton crushing monster as they have to be anchored to the floor when you operate them.

 

Share this post


Link to post
Share on other sites
8 hours ago, SNACR said:

The following fuses have blown in a three-phase charger I'm attempting to repair. They're marked 690v but are much pricier than 500v for some reason. They are on the input side so the voltage shouldn't exceed 500v but there are hefty solenoids and transformers so is there some back emf type thing or something I'm missing?

690v

http://uk.rs-online.com/web/p/cartridge-fuses/8068405/

500v

http://uk.rs-online.com/web/p/cartridge-fuses/2303474/

 

 

 

Might have been selected for the breaking capacity - 160KA vs 120KA.

If you can find a 10x38mm F rated speed with 160KA breaking capacity cheaper should be OK with 500V rating.

Check the above specs with manufacturer's data sheet as I only did a quick check.

Could ring up local electrical factors and ask them to have a look for that spec (original or 500V equivalent). Or ping a few emails to the sellers specialising in industrial electrics on ebay who have some equivalent or near equivalent to see if they can source.

This seller on Ebay might be worth approaching

http://www.ebay.co.uk/itm/B10X38S-20A-Fuse-fuse-gG-ceramic-industrial-20A-500VAC-10x38mm-420020-/192051522557?hash=item2cb729abfd:g:vCgAAOSwEzxYTtMQ

 

Also worth checking owner's / service manual or OEM manufacturer of the equipment if they are still trading if they have a spec for the fuse.

 

 

 

Edited by onlyme

Share this post


Link to post
Share on other sites
On 10/09/2017 at 19:53, onlyme said:

Might have been selected for the breaking capacity - 160KA vs 120KA.

If you can find a 10x38mm F rated speed with 160KA breaking capacity cheaper should be OK with 500V rating.

Check the above specs with manufacturer's data sheet as I only did a quick check.

Could ring up local electrical factors and ask them to have a look for that spec (original or 500V equivalent). Or ping a few emails to the sellers specialising in industrial electrics on ebay who have some equivalent or near equivalent to see if they can source.

This seller on Ebay might be worth approaching

http://www.ebay.co.uk/itm/B10X38S-20A-Fuse-fuse-gG-ceramic-industrial-20A-500VAC-10x38mm-420020-/192051522557?hash=item2cb729abfd:g:vCgAAOSwEzxYTtMQ

 

Also worth checking owner's / service manual or OEM manufacturer of the equipment if they are still trading if they have a spec for the fuse.

 

 

 

Just ordered the exact ones in the end there wasn't a real cheaper alternative through RS only ebay, and had assumed there would also be in RS, but couldn't be bothered to wait for delivery from ebay - most of the really cheap on ebay were from China so not sure on quality but having said that the OEM are made in India.

Share this post


Link to post
Share on other sites

The fuses have arrived along with three pairs of pliers and a soldering station, I probably don't really need, impulse bought - given the range at RS that could have been much worse.

Share this post


Link to post
Share on other sites
1 hour ago, SNACR said:

The fuses have arrived along with three pairs of pliers and a soldering station, I probably don't really need, impulse bought - given the range at RS that could have been much worse.

Haha, enjoy! I've got an old Metal RF one (instant heat and can sink a lot of heat through even a small tip), mind you I bet the terminal connectors on your forklifts would require rather more than that....

Share this post


Link to post
Share on other sites
12 minutes ago, SNACR said:

Looks like the microprocessor boards are ok, and not fried, but the LGBT diode, or something, has gone into a permanent safe space.

Good job you got that Soldering Iron. :Jumping:

What's the part no. of the IGBT?  Remember flux is your friend and solder wick helps too cleaning up the old pad, trickiest part is sometimes getting the part cleanly off the board without damaging tracks, usually plain sailing after that.

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

  • Recently Browsing   0 members

    No registered users viewing this page.