[Mobile-Portable] Automotive Circuit Breakers VS Fuses ?

Fri Nov 27 17:06:58 EST 2009

FWIW, Ten-Tec used to offer a fast acting circuit breaker, PN 1140, for use
with their 20 A transceivers if they weren't powered by their crowbar
response power supplies. These were designed to act quickly enough to trip
before the finals fried due to overload, probably faster than a fuse. 

I know that they were an off the shelf product, just don't remember the
manufacturer or model #. Perhaps some T-T owner can point folk in the right
direction.

Regards, Joel
Joel R. Hallas, W1ZR
-----Original Message-----
From: mobile-portable-bounces at mailman.qth.net
[mailto:mobile-portable-bounces at mailman.qth.net] On Behalf Of K0DAN
Sent: Friday, November 27, 2009 4:51 PM
To: Mobile-Portable Reflector
Subject: Re: [Mobile-Portable] Automotive Circuit Breakers VS Fuses ?

Take a look at Santa Fe Distributors...
http://www.s-f-d.com/main.html
...they're a distributor for a lot of mobile audio/video products. alarms, 
RF products, etc. They have a lot of installer's supplies for the big high 
power mobile systems, which include fuse blocks, etc.

See if you can find some ideas in their catalog...

They do not sell to the general public, but it's not too hard to get a 
dealer's account with them. If you juts want to get a few items let me know 
and I'll you pricing & delivery.

73

Dan
K0DAN

----- Original Message ----- 
From: "N5WV" <n5wv at comcast.net>
To: "Mobile-Portable Reflector" <mobile-portable at mailman.qth.net>
Sent: Friday, November 27, 2009 3:16 PM
Subject: Re: [Mobile-Portable] Automotive Circuit Breakers VS Fuses ?

> Bill , Im speechless , Your thoughts on this circuit protection topic puts

> the circuit breakers back in the box for another project one day. "maybe ,

> and as long as the units being protected can easily be replaced". My next 
> step is to find fuses that will accept 4ga cable. I see where some allow 
> one to simply insert the cable and lock down a set screw but most are 
> rated at 6ga max. Im sure I will find one large enough or just get the 
> ones with standard connectors on each end. My mechanic told me the other 
> day , with all of this high powered car stereo equipment being sold today 
> the stores are offering large fuses to there customers. I will start with 
> DX Eng and Powerwerx and go from there. Everyones comments were just great

> , 73 to all , de Randy N5WV
> ----- Original Message ----- 
> From: "WD8ARZ" <wd8arz at comcast.net>
> To: "Mobile-Portable Reflector" <mobile-portable at mailman.qth.net>
> Sent: Friday, November 27, 2009 5:04:56 AM GMT -06:00 US/Canada Central
> Subject: Re: [Mobile-Portable] Automotive Circuit Breakers VS Fuses ?
>
> It isnt just about the response timing of circuit breakers to fuses (where
> fuses win hands downs), it is also about failures of breakers to function 
> a
> all. Circuit breakers have been known to fail, not function period. I have
> never heard of a fuse doing that .... hi
>
> For the topic of a circuit breakers to protect small gauge feed wire 
> through
> a firewall to a fuse system in a Rigblaster ..... the higher the current 
> and
> the longer the wire run, the more I would trust fuses over circuit 
> breakers.
>
> Fuses can not only be chosen for the amp rating, but also for the timing
> required to open the circuit. Circuit breakers are slower, period. A lot 
> of
> electronics can be damaged in a fuse breaker system. A fuse will blow on
> voltage / current transients that will protect electronics, that a circuit
> breaker will not respond to.
>
> Look at automotive, industrial and home systems. Note how many of the
> systems uses fuses, and when / where breakers are used. Even where there 
> are
> breakers, there are fuses up line of those. Home breakers are for AC
> systems. Look at the solid state electronics in your home on those AC
> systems. Bet the electronics is fused.
>
> In the case of the Ten Tec that used a magnetic circuit breaker.... that 
> was
> a special application to protect the finals. It was easy during tune up to
> overload the finals, and that happen so easily, fuses would have been an
> aggravation. The magnetic circuit breaker was a special design that would
> trip when current got to high to the finals, but prior to the finals
> blowing. Bottom line was the poor transmitter design that needed that
> special breaker design.
>
> Power interruptions create voltage spikes and current surges. Inductive
> components have magnetic fields that get large during a spike / surge. 
> When
> the circuit flow is stopped during a blowing fuse / breaker situation, the
> counter emf creates a spike / surge in the opposite direction in the 
> circuit
> creating flows through diodes and other solid state components that may 
> not
> tolerate those events. Fuses blow sooner keeping the spikes / surges to a
> minimum .... circuit breakers that trip during the same event will take
> longer to respond, thus the likely hood of higher voltage spikes, larger
> current surges, and a longer dwell exposure time of sensitive electronics 
> to
> the abnormal power condition during that even.
>
> MOV suppressors are a god send to help control that, BUT too many hits on 
> a
> MOV and they fail to function and need to be replaced. When do you know 
> that
> a MOV fails? If it didnt fail shorted, you dont until electronics is 
> damage
> it was meant to protect. Because of the fast propagation of these voltage
> spikes / current surges followed by counter electromotive voltages /
> currents, fuses are need to protect electronics. Still use the metal oxide
> varisters and other protective devices where you can, just expect to have 
> to
> replace them over time / multiple events that trigger them (such as in 
> your
> power strips).
>
> 73 from Bill - WD8ARZ
> http://hflink.net/qso/
>
> ----- Original Message ----- 
> From: "N5WV" <n5wv at comcast.net>
> To: <mobile-portable at mailman.qth.net>
> Sent: Thursday, November 26, 2009 4:02 AM
> Subject: [Mobile-Portable] Automotive Circuit Breakers VS Fuses ?
>
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