Fuse keeps blowing- any ideas why?
Aris Theocharides
Is there any good reason why an amplifier fuse (T1A 250V) would keep
blowing? The fuse generally goes when I turn on the amplifier (Creek 4140
S2).
I have recently moved house, and have had 4 fuses blow in one week. The
fuse is the power supply type, in a little accessible plastic socket at
the back of the unit near the power cable plug.
PS: Are the T1A fuses just 1 Amp fuses (does T1A 250V == 1A 250V ?)
Many thanks if you have an idea.
Aris
BTW: The speaker cables are ok and as far as I can tell there are no
shorts happening there.
--
Aris Theocharides
Xedoc Software Development
Melbourne, Australia
Graeme Gill
>Is there any good reason why an amplifier fuse (T1A 250V) would keep
>blowing? The fuse generally goes when I turn on the amplifier (Creek 4140
>S2).
Transformer turn on surge. Whether it blows or not will depend
on which point of the AC waveform you happen to turn it on on.
A lot of current flows for the half cycle or so it takes
to establish the magnetic field in the transformer core.
>PS: Are the T1A fuses just 1 Amp fuses (does T1A 250V == 1A 250V ?)
You could try a 1 amp "slow-blow" fuse, or a sligntly
larger (1.5 or 2 amp) standard (fast blow) fuse. A slightly
larger fuse should still give you adequate protection
from gross faults.
(It would probably be prudent to try the amp out in
a safety switch outlet to make sure it doesn't have an active
to earth fault.)
Graeme Gill.
JerryGee
<a...@xedoc.com.au> writes:
It is obvious that your amp is drawing more than 1 amp of current if your fuse
it blowing......you have a short somewhere
C.M. Hicks
>Is there any good reason why an amplifier fuse (T1A 250V) would keep
>blowing? The fuse generally goes when I turn on the amplifier (Creek 4140
>S2).
>I have recently moved house, and have had 4 fuses blow in one week. The
>fuse is the power supply type, in a little accessible plastic socket at
>the back of the unit near the power cable plug.
>PS: Are the T1A fuses just 1 Amp fuses (does T1A 250V == 1A 250V ?)
Yes, but it's not quite so simple. Fuses come in several flavours, the
more common ones being FF, F and T (so they are marked FF1A, F1A and T1A).
You should use T1A as specified. Email me if you want to know the dif-
ferences.
Christopher
--
==============================================================================
Christopher Hicks | It certainly isn't above-board in the shop (5,3,7)
c...@eng.cam.ac.uk |
==============================================================================
Bob Neidorff
CAUTION! BE CAREFUL!
DON'T BLINDLY REPLACE FUSES WITH DIFFERENT TYPES!
I believe that you said that this was a Creek. Call Creek and
ask them the specifications for the fuse which is correct. If
you swap a slow blow fuse for a fast blow fuse (for example)
and something goes wrong, you could risk a fire or more
expensive damage.
--
Bob Neidorff; Unitrode I. C. Corp. | Internet: neid...@uicc.com
7 Continental Blvd. | Voice : (US) 603-429-8541
Merrimack, NH 03054-0399 USA | FAX : (US) 603-424-3460
BRETT KIPPS
>From: neid...@uicc.com (Bob Neidorff)
>Subject: Re: Fuse keeps blowing- any ideas why?
>Date: Mon, 16 May 1994 14:01:35 GMT
>CAUTION! BE CAREFUL!
i tend to agree with our friend Bob here. A Creek amp eh ? well even so
not really something to be taken that light-heartedly..
using a slow-blow fuse? hmmm....depends depends...but in my opinion...NOT
worth the risk in this particular case. As Mr. Neidorff suggests, call Creek
and see what they have to say. Obviously ur getting some surges there and
thats why its blowing quite simple. Do u have any other fuse appliances
like this? do they blow their fuses in a similar manner? (eg microwave oven)
the next step i guess is things like voltage regulators..spike protectors..
or even more u could get ur supply looked at ..coz this sorta thing happening
as frequently as u suggest isnt good. And should be looked at in general.
..brett
Micromine
: using a slow-blow fuse? hmmm....depends depends...but in my opinion...NOT
: worth the risk in this particular case. As Mr. Neidorff suggests, call Creek
: and see what they have to say. Obviously ur getting some surges there and
: thats why its blowing quite simple. Do u have any other fuse appliances
: like this? do they blow their fuses in a similar manner? (eg microwave oven)
: the next step i guess is things like voltage regulators..spike protectors..
: or even more u could get ur supply looked at ..coz this sorta thing happening
: as frequently as u suggest isnt good. And should be looked at in general.
I prefer to use fast blow fuses... It sounds to me that either:
a) A fuse blew normally and is being replaced with the incorrect type.
b) You have a fault in the amp.
If the correct type fuse keeps blowing you definately have a fault.
An alternative for fuses are small inline circuit breakers... More
expensive but they are really neat and offer better protection.
Simon.
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Graeme Gill
>If the correct type fuse keeps blowing you definately have a fault.
There is no "definitely" about it. Designers are not infallible.
While a fault should certainly be investigated first, and
while the fuse should be replaced (initially) with a replacement of the
manufacturers specifications, if after investigation:
1) No fault is found and: 2) the recommended fuses keep blowing,
then there is the possibility that the designers stuffed up, and
it needs a slightly bigger/slower fuse. Perhaps the designers
tested with a supply with a high source impedance, perhaps the
gear was tested at 220 V, not 240 Volts, perhaps certain components
are at tolerance extremes (ie. the filter elctros. Their
usual spec is something like -20 to +50%. If your electros
are at +50% capacity, then you will probably get a turn on surge
about 50% over nominal.)
Fuses are hardly a high tolerance safety device. Things
can catch fire without blowing fuses. But they do protect
against gross faults such as short circuits in the incoming
supply.
Graeme Gill.
Bill Vermillion
>: using a slow-blow fuse? hmmm....depends depends...but in my opinion...NOT
>: worth the risk in this particular case.
>I prefer to use fast blow fuses... It sounds to me that either:
You should use the fuse the equipment is designed for. In
devices with large inrush a slow blow is needed. Otherwise you
have to put in a higher value regular fuse to keep from
blowing on startup, and may inadvertanly fry something.
>An alternative for fuses are small inline circuit breakers... More
>expensive but they are really neat and offer better protection.
A word about circuit breakers offerning more protection.
** ** ****** *** ** ** ****
** ** ** ** ** ** *** ** ** **
** ** ** ** ** ** **** ** **
** * ** ***** ** ** ** **** **
******* ** ** ** ** ** *** ** ***
*** *** ** ** ** ** ** ** ** **
** ** *** ** *** ** ** *****
Circuit breakers are mechanical and can fail in the non-safe
mode. I've never seen a fuse blow when it wasn't supposed to,
but I've seen them blow when they weren't.
Ever see smoke pouring from a light switch with the plastic
cover on the switch melting, and the AC wires glowing bright
red? I have. Circuit breaker didn't trip and acted like a
nice bus bar. Good thing it happened during the day when
people were around.
Fuses are the way to go to really be sure!
--
Bill Vermillion - bi...@bilver.oau.org | bill.ve...@oau.org