"Miracle switch" failures

[Ron Van Putte]

JOddino wrote:

>I might need to apologize.  I keep thinking everyone remembers mechanical tuners.  Perhaps you are too young.
>  
>
I doubt anybody has called John Ferrell too young in a long time.  <VBG>

Ron Van Putte

>----- Original Message -----
>From: "JOddino" <JOddino at socal.rr.com>
>To: <discussion at nsrca.org>
>Sent: Tuesday, March 25, 2003 9:04 AM
>Subject: Re: "Miracle switch" failures
>
>
>  
>
>>First of all the electronic "switch" is a device used in a linear mode
>>    
>>
>when
>  
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>>regulating.  If the input voltage drops below the set regulated voltage it
>>will saturate and if it is a good regulator will have an on resitance of
>>    
>>
>50
>  
>
>>milliohms or so.  I didn't hear if he checked the input voltage under the
>>same conditions he measured 4.2 volts on the output.  Either the input
>>voltage was low or the on resistance was high and/or the load current was
>>too high.
>>Second, the electronic switch/regulator is not in parallel or tandem with
>>the mechanical switch.  If the mechanical switch fell off the plane you
>>would not lose power.  In fact I don't even have a mechanical switch on my
>>new plane.  I use a safeing plug to turn it off.
>>The device I use protects itself and I wouldn't know how to make it fail
>>within its rated operating conditions.  You can put a dead short on the
>>output and not hurt anything.  Try that with your mechanical switch but
>>    
>>
>have
>  
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>>a fire extinguisher handy.
>>Think about how long the old mechanical tuners on TVs lasted.  When was
>>    
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>the
>  
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>>last time you heard of an electronic tuner going bad?  I rest my case.
>>Jim
>>----- Original Message -----
>>From: "John Ferrell" <johnferrell at earthlink.net>
>>To: <discussion at nsrca.org>
>>Sent: Tuesday, March 25, 2003 6:24 AM
>>Subject: Re: "Miracle switch" failures
>>
>>
>>    
>>
>>>If I understand the failure conditions, the electronic switch was
>>>      
>>>
>>paralleled
>>    
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>>>with a mechanical switch.
>>>That is not something that would be considered a 'normal' configuration
>>>      
>>>
>>for
>>    
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>>>the electronic switch.
>>>I refrain from using these devices because I have never had a switch
>>>      
>>>
>>problem
>>    
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>>>with a Futaba switch.
>>>Most electronic power switching devices that I am aware of are MOSFET
>>>technology.
>>>These devices switch many amps with great reliability, but are extremely
>>>vulnerable to voltage spikes.
>>>The inputs and outputs are protected by internal diodes from these
>>>      
>>>
>spikes.
>  
>
>>>I have been unable to puzzle out if there is an unprotected input-output
>>>junction.
>>>Here is a possible scenario:
>>>    The mechanical switch is turned off generating a spike that damages
>>>      
>>>
>>the
>>    
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>>>elecronic switch in a failure
>>>    mode that drags down the receiver voltage feed.
>>>My personal conclusion is that either switch will work as advertised,
>>>      
>>>
>but
>  
>
>>>when used in tandem it is
>>>not a matter of if it will fail but when it will fail.
>>>
>>>John Ferrell
>>>6241 Phillippi Rd
>>>Julian NC 27283
>>>Phone: (336)685-9606
>>>Dixie Competition Products
>>>NSRCA 479 AMA 4190  W8CCW
>>>"My Competition is Not My Enemy"
>>>
>>>
>>>
>>>----- Original Message -----
>>>From: <s.vannostrand at kodak.com>
>>>To: <discussion at nsrca.org>
>>>Sent: Monday, March 24, 2003 1:16 PM
>>>Subject: "Miracle switch" failures
>>>
>>>
>>>      
>>>
>>>>I know there are some vendors and users of those voltage regulators
>>>>        
>>>>
>with
>  
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>>>>the built in switch.  One mfg calls it the miracle switch.  I have
>>>>        
>>>>
>one,
>  
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>>>>hooked it up, am using it with no problems so far, but I may be just
>>>>        
>>>>
>>>lucky.
>>>      
>>>
>>>>Is there a right/wrong way to hook up the connectors?  I have a radio
>>>>        
>>>>
>>>south
>>>      
>>>
>>>>one and there are two male connectors (one for the receiver, and one
>>>>        
>>>>
>for
>  
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>>>>recharging), and one female (for the battery input).  The system works
>>>>        
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>>>with
>>>      
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>>>>either male plugged into the receiver.  Based on Wayne's sad story
>>>>        
>>>>
>below
>  
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>>>>I'm wondering if maybe only one should be connected to the receiver in
>>>>order to maintain voltage when the switch fails.
>>>>
>>>>Anyone know if there is a sure way to tell if you have it hooked up
>>>>correctly?
>>>>
>>>>
>>>>Wayne writes, " I am/was using a MCI Miracle switch that is a
>>>>        
>>>>
>regulator
>  
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>>>and
>>>      
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>>>>has fail safe if the mechanical switch contacts fail the switch stays
>>>>        
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>on
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>>>>all the time.   I tested the battery and it checked at 6.5v.  I
>>>>        
>>>>
>checked
>  
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>>>>through the charge port and 6.5v.  But when I checked it through the
>>>>connector to the receiver it only registered 4.25v  just below the
>>>>receivers voltage threshold. "
>>>>
>>>>--Lance
>>>>
>>>>
>>>>
>>>>
>>>>=====================================
>>>># To be removed from this list, send a message to
>>>># discussion-request at nsrca.org
>>>># and put leave discussion on the first line of the body.
>>>>#
>>>>
>>>>
>>>>        
>>>>
>>>=====================================
>>># To be removed from this list, send a message to
>>># discussion-request at nsrca.org
>>># and put leave discussion on the first line of the body.
>>>#
>>>
>>>
>>>      
>>>
>>=====================================
>># To be removed from this list, send a message to
>># discussion-request at nsrca.org
>># and put leave discussion on the first line of the body.
>>#
>>
>>
>>    
>>
>
>=====================================
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>  
>

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