[Amps] Fuses

[James R Carr]

Who makes it and what's the model number? I'd like to see the specs on it 
especially the UL test results. When I retired in 2000 the only way they 
were able to get a breaker to clear a fault in less than three full cycles 
was to put 18" of wire between it and the buss bars. And even then it didn't 
get down to 1/2 cycle. Fuses were tested as a bolted fault across the buss 
bars.
----- Original Message ----- 
From: "Paul Kraemer" <elespe at lisco.com>
To: "AMPS" <amps at contesting.com>
Sent: Friday, January 07, 2011 6:50 PM
Subject: Re: [Amps] Fuses


> It is a terminology thing as in magnetic / hydraulic trip
> Also, we routinely use supplemental IEC protection devices that have an
> adjustable thermal trip plus a near instantaneous overcurrent trip
> Actual tests in our shop have demonstrated to us that they will in fact 
> trip
> faster than a fast semiconductor fuse will blow
> That is why we frequently install them ahead of motor drives to protect 
> the
> expensive semiconductor protection fuses.
> Paul K0UYA
> ----- Original Message ----- 
> From: "James R Carr" <n7fcf at hctc.com>
> To: "Jim Thomson" <jim.thom at telus.net>; <amps at contesting.com>
> Sent: Friday, January 07, 2011 8:01 PM
> Subject: Re: [Amps] Fuses
>
>
>> Where pray tell do you get a hydraulic breaker? I have installed several
>> thousand over the years but have yet to see one filled with oil.
>> As for current limiting devices, the fastest breaker will hold in for
>> three
>> to seven full cycles. To be current limiting, a fuse has to clear in less
>> than 1/2 cycle.
>> Jim
>> N7FCF
>> ----- Original Message ----- 
>> From: "Jim Thomson" <jim.thom at telus.net>
>> To: <amps at contesting.com>
>> Sent: Friday, January 07, 2011 4:02 PM
>> Subject: [Amps] Fuses
>>
>>
>>> Date: Fri, 7 Jan 2011 10:45:07 -0500
>>> From: "Carl" <km1h at jeremy.mv.com>
>>> Subject: Re: [Amps] Fuses
>>>
>>> Just dont over fuse. The usual 1200W out amp uses 10-12A; 15A for
>>> 1500-2200W, etc at 240VAC.
>>>
>>> Carl
>>> KM1H
>>>
>>> ##  why  didn't they just get off the..'get cheap program'  and use a
>>> fast
>>> breaker ??
>>> Ideally, a 2 x pole, 15A , controlled magnetic hydraulic breaker   would
>>> be the 1st choice,
>>> one with an..."instant trip" .    The instant trip types are the 
>>> fastest.
>>> They just remove the oil
>>> from the reservoir, so it's super fast.  The normal, slow, and motor
>>> start
>>> types  just use different grades
>>> of viscosity for the oil used.   I use em all the time for my various HB
>>> projects.   Any HB  B+  supply
>>> always gets a super fast magnetic hydraulic  breaker..for the primary of
>>> the plate xfmr.   [they are also NOT
>>> affected by ambient temp either].
>>>
>>> ##  My Drake L4PS power supplies use 2 x 15A breakers, spaced a few
>>> inch's
>>> apart.  One per hot leg.
>>> These are the simple  push button type.  [ push to re-set].   The
>>> advantage  of the 2 x pole type noted above is..
>>> the trip bar between em ensures  both sides of the 240 line open up.
>>>
>>> ##  You would think for the megabuck that alpha charges for their amps,
>>> that they would not cheap out..and use
>>> simple fuses !
>>>
>>> Later... Jim   VE7RF
>>>
>>>
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>>
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