Can't find a 20A 250V glass fuse

R

RJ

Guest
My son's scooter uses a 20A 250V glass fuse. Boy has this been
impossible to find. I can however find the fuse in a ceramic
configuration. Is is okay to replace a glass fuse with a ceramic one
of the same amps etc.?
 
RJ wrote:
My son's scooter uses a 20A 250V glass fuse. Boy has this been
impossible to find. I can however find the fuse in a ceramic
configuration. Is is okay to replace a glass fuse with a ceramic one
of the same amps etc.?
Click to expand...
Yes, usually. The ceramic versions often have a higher interruption
current rating than the glass ones.

Are you sure you have any use for the 250 volt rating?

Would the fuse ever have to interrupt more than 32 volts DC?
These can interrupt 1000 amps at 32 volts DC:
http://www.bussmann.com/library/bifs/2004.pdf
Is there any chance that the scooter can exceed this?
It is the slow blow (high inrush version).

Here is the fast acting version:
http://www.bussmann.com/library/bifs/2001.pdf
It has the same interruption rating.

--
John Popelish
 
On Wed, 30 Jun 2004 18:24:01 -0700, RJ wrote
(in article <ec939b78.0406301724.10e8bbba@posting.google.com>):

My son's scooter uses a 20A 250V glass fuse. Boy has this been
impossible to find. I can however find the fuse in a ceramic
configuration. Is is okay to replace a glass fuse with a ceramic one
of the same amps etc.?
Click to expand...
If this is the common 1-1/4 inch long, 1/4-inch diameter form factor (3AG?),
it must be the most common fuse on the road. Look in automotive stores. All
the pre-90's models (except German) cars use these fuses.

The 250 volt rating is a maximum, of course, and you can use any 20-amp fuse
with a voltage rating that encompasses your scooter's voltage.

Good luck,
--
DaveC
me@privacy.net
This is an invalid return address
Please reply in the news group
 
On Thu, 1 Jul 2004 07:07:15 -0700, DaveC wrote
(in article <0001HW.BD0968A30162264CF02845B0@news.individual.net>):

The 250 volt rating is a maximum, of course, and you can use any 20-amp fuse
with a voltage rating that encompasses your scooter's voltage.
Click to expand...
I should add...

AND is the same type (ie, fast-blow) as the original fuse.
--
DaveC
me@privacy.net
This is an invalid return address
Please reply in the news group
 
John Popelish <jpopelish@rica.net> wrote in message news:<40E377D0.54411A2@rica.net>...
RJ wrote:

My son's scooter uses a 20A 250V glass fuse. Boy has this been
impossible to find. I can however find the fuse in a ceramic
configuration. Is is okay to replace a glass fuse with a ceramic one
of the same amps etc.?

Yes, usually. The ceramic versions often have a higher interruption
current rating than the glass ones.

Are you sure you have any use for the 250 volt rating?

Would the fuse ever have to interrupt more than 32 volts DC?
These can interrupt 1000 amps at 32 volts DC:
http://www.bussmann.com/library/bifs/2004.pdf
Is there any chance that the scooter can exceed this?
It is the slow blow (high inrush version).

Here is the fast acting version:
http://www.bussmann.com/library/bifs/2001.pdf
It has the same interruption rating.
Click to expand...

Thanks for the information. All I know is that the scooter manual
lists the motor at 24V 250W and the fuse had 20A 250V on it. Why I
need the 250V fuse is beyond my comprehension. Requesting your advise
please.
 
"RJ" <rjjensen@hotmail.com> wrote in message
news:ec939b78.0407010647.28bf441b@posting.google.com...
John Popelish <jpopelish@rica.net> wrote in message
news:<40E377D0.54411A2@rica.net>...
RJ wrote:

My son's scooter uses a 20A 250V glass fuse. Boy has this been
impossible to find. I can however find the fuse in a ceramic
configuration. Is is okay to replace a glass fuse with a ceramic one
of the same amps etc.?

Yes, usually. The ceramic versions often have a higher interruption
current rating than the glass ones.

Are you sure you have any use for the 250 volt rating?

Would the fuse ever have to interrupt more than 32 volts DC?
These can interrupt 1000 amps at 32 volts DC:
http://www.bussmann.com/library/bifs/2004.pdf
Is there any chance that the scooter can exceed this?
It is the slow blow (high inrush version).

Here is the fast acting version:
http://www.bussmann.com/library/bifs/2001.pdf
It has the same interruption rating.


Thanks for the information. All I know is that the scooter manual
lists the motor at 24V 250W and the fuse had 20A 250V on it. Why I
need the 250V fuse is beyond my comprehension. Requesting your advise
please.
Click to expand...
You don't. A 32-volt automotive fuse will be fine. They put in a 250V
fuse at the factory because that's probably what they had on hand, or
a batch of 20A 250V fuses was cheaper than a batch of 20A 32V fuses.
It's a perfectly safe replacement, but not necessary.

Years ago, I and some other people were wondering, "what the heck is
a voltage rating on a fuse?" It turns out that it's the maximum open-
circuit voltage at which the fuse can safely interrupt its rated
current.

I've seen 32V fuses in a 240V circuit. They work fine, until one
blows - they blow, literally! I've seen one shoot that little
bayonet cap half-way across a factory floor. The 32-volt fuse
makes a nice arc at 240, you see.

I saw a 20A, 15,000V fuse once, that somebody had made a typo
when they ordered it. It was a USAF shop, so we couldn't send it
back. It was shaped just like a 3AG, but about 3" diameter and
about a foot long. The glass tube was about 3/8" thick, and it
was full of sand, with a ceramic core with 5 or 6 fine wires
in parallel, wound around it at about 3" per turn.

Hope This Helps!
Rich
 
RJ wrote:
John Popelish <jpopelish@rica.net> wrote in message news:<40E377D0.54411A2@rica.net>...
RJ wrote:

My son's scooter uses a 20A 250V glass fuse. Boy has this been
impossible to find. I can however find the fuse in a ceramic
configuration. Is is okay to replace a glass fuse with a ceramic one
of the same amps etc.?

Yes, usually. The ceramic versions often have a higher interruption
current rating than the glass ones.

Are you sure you have any use for the 250 volt rating?

Would the fuse ever have to interrupt more than 32 volts DC?
These can interrupt 1000 amps at 32 volts DC:
http://www.bussmann.com/library/bifs/2004.pdf
Is there any chance that the scooter can exceed this?
It is the slow blow (high inrush version).

Here is the fast acting version:
http://www.bussmann.com/library/bifs/2001.pdf
It has the same interruption rating.

Thanks for the information. All I know is that the scooter manual
lists the motor at 24V 250W and the fuse had 20A 250V on it. Why I
need the 250V fuse is beyond my comprehension. Requesting your advise
please.
Click to expand...
I have not been able to get back for a couple days, but it looks like
others have given you the thumbs up on the low voltage replacement,
and I concur.

As long as the fuse is rated for at least the supply voltage it may
have to interrupt and the supply is not capable of a fault (short
circuit) current greater than the interruption rating of the fuse, it
should function safely.

There are 4 important ratings for any fuse.

long term carrying current
overload time curve
interrupting current limit
interrupting voltage rating

--
John Popelish
 
"Rich Grise" <null@example.net> wrote in message news:<x71Fc.24759$DT5.22892@nwrddc03.gnilink.net>...
"RJ" <rjjensen@hotmail.com> wrote in message
news:ec939b78.0407010647.28bf441b@posting.google.com...
John Popelish <jpopelish@rica.net> wrote in message
news:<40E377D0.54411A2@rica.net>...
RJ wrote:

My son's scooter uses a 20A 250V glass fuse. Boy has this been
impossible to find. I can however find the fuse in a ceramic
configuration. Is is okay to replace a glass fuse with a ceramic one
of the same amps etc.?

Yes, usually. The ceramic versions often have a higher interruption
current rating than the glass ones.

Are you sure you have any use for the 250 volt rating?

Would the fuse ever have to interrupt more than 32 volts DC?
These can interrupt 1000 amps at 32 volts DC:
http://www.bussmann.com/library/bifs/2004.pdf
Is there any chance that the scooter can exceed this?
It is the slow blow (high inrush version).

Here is the fast acting version:
http://www.bussmann.com/library/bifs/2001.pdf
It has the same interruption rating.


Thanks for the information. All I know is that the scooter manual
lists the motor at 24V 250W and the fuse had 20A 250V on it. Why I
need the 250V fuse is beyond my comprehension. Requesting your advise
please.

You don't. A 32-volt automotive fuse will be fine. They put in a 250V
fuse at the factory because that's probably what they had on hand, or
a batch of 20A 250V fuses was cheaper than a batch of 20A 32V fuses.
It's a perfectly safe replacement, but not necessary.

Years ago, I and some other people were wondering, "what the heck is
a voltage rating on a fuse?" It turns out that it's the maximum open-
circuit voltage at which the fuse can safely interrupt its rated
current.

I've seen 32V fuses in a 240V circuit. They work fine, until one
blows - they blow, literally! I've seen one shoot that little
bayonet cap half-way across a factory floor. The 32-volt fuse
makes a nice arc at 240, you see.

I saw a 20A, 15,000V fuse once, that somebody had made a typo
when they ordered it. It was a USAF shop, so we couldn't send it
back. It was shaped just like a 3AG, but about 3" diameter and
about a foot long. The glass tube was about 3/8" thick, and it
was full of sand, with a ceramic core with 5 or 6 fine wires
in parallel, wound around it at about 3" per turn.

Hope This Helps!
Rich
Click to expand...

Thanks Rich and John. I got the 32V fuse today and it is working
fine. This fuse was easy to find.
 
Rich Grise wrote...
I saw a 20A, 15,000V fuse once, that somebody had made a typo
when they ordered it. It was a USAF shop, so we couldn't send it
back. It was shaped just like a 3AG, but about 3" diameter and
about a foot long. The glass tube was about 3/8" thick, and it
was full of sand, with a ceramic core with 5 or 6 fine wires
in parallel, wound around it at about 3" per turn.
Click to expand...
It would have been even more interesting if the contract had
required that components be 100% tested for all functionality
before leaving the factory.

Thanks,
- Win

(email: use hill_at_rowland-dot-org for now)
 
"Winfield Hill" <Winfield_member@newsguy.com> wrote in message
news:cc7ecu0n7n@drn.newsguy.com...
Rich Grise wrote...

I saw a 20A, 15,000V fuse once, that somebody had made a typo
when they ordered it. It was a USAF shop, so we couldn't send it
back. It was shaped just like a 3AG, but about 3" diameter and
about a foot long. The glass tube was about 3/8" thick, and it
was full of sand, with a ceramic core with 5 or 6 fine wires
in parallel, wound around it at about 3" per turn.

It would have been even more interesting if the contract had
required that components be 100% tested for all functionality
before leaving the factory.
Click to expand...
Ah but it is a wonder that someone in military procurement didn't specify
the sure fire test of a fuses functionality - if it operates satisfactorily,
it was good and passes the test :).
--
Don Kelly
dhky@peeshaw.ca
remove the urine to answer

Thanks,
- Win

(email: use hill_at_rowland-dot-org for now)
Click to expand...
 
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