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Amp Shutting Down, need help

I have a Cary 7.250 brand new amp that shuts down after 20 seconds in my NYC apartment. I have sent the unit back to Cary where it tests fine. I have tried the unit at my friend’s apartment and his place of work and it works fine. The unit is 100% in working order. After talking to many people I was told to attach a 50' extension cord and low and behold it worked.

The good news is that I have a dedicated 20amp circuit to this outlet. My voltage reads 118 volts and Cary said that is not a problem as the unit will work between 90 and 130 volts. I have tested for voltage on the negative lead to ground and there is no stray voltage. I have also tried the unit on other outlets in the apartment and the same problem occurs.

My mono blocks and all other components work just fine. So I’d love to hear suggestions as to how to get rid of this 50’ extension cord?

Thanks in advance.
sailcappy
jea48
4,425 posts
 
4. The White and Black wires connected to the circuit breaker seem to be 10 guage.

Is the breaker a GFCI (Ground Fault Circuit Interrupter) or an AFCI (Arc Fault Circuit Interrupter)? These type of breakers have a test trip push button on them.

When I switched the Cary on the voltage did not change. Nor did it change during the 20 seconds it takes for the 15amp Cary breaker to trip.
Well that is good for the integrity of the branch circuit wiring. That tells me with the load connected the branch circuit maintained the supply voltage with little or no VD, (voltage drop) through the high inrush current cycle.

That also tells me the branch circuit is capable of delivering the inrush current draw of the primary winding of the power transformer.

However when the breaker did trip for a split second the votage meter read 112 volts.
I have a feeling the VD drop happened before the trip.....
Question is what is it and why?

At this point it would be good to hear from Almarg or Ralpf of Atma-Sphere Music Systems.

As for your friends theory he could be onto something.

By chance does your friend have a clamp on amprobe so you could measure the inrush current draw of the amp on startup?

As for the circuit breaker used on the Cary.... Is the switch actually a breaker? The handle trips position and has to be reset? If it is indeed a breaker the more times it is tripped the weaker it becomes.

Just can't beat a fuse for overcurrent protection for audio equipment.....
Jim
jea48
4,425 posts
 
Jea48: As you know, "inrush" current is typically instantanious - with PS filter caps charged to 95+% within a few seconds, or so, for most high-power amps.
08-15-12: Metro04

Note he's stating the breaker consistantly trips "after 20 seconds",
08-15-12: Metro04

Metro04,

Good point....

His recent noted voltage drop to 112, only at the moment of trip, is curious.
Agree.....

For a thermo-magnetic breaker, you'd expect to see sustained high current voltage drop right up until tripping vs the virtually unaffected static 118 - as if the power supply wasn't even pulling current (?).

Are we 100% sure what the trip mechanism is?

The fact that the 50' extension cord allows the amp to work without tripping the overcurrent protection is baffling to say the least.

Like I said earlier it could be working as a current limiter... I am not so sure now, that is case...



If Sailcappy lives in a high rise apartment building hard telling what the power quality of the AC power looks like.

I wonder if Sailcappy has talked to the superintendent or head of maintenance about his problem? They may split the cost for a "Power Quality Company" to check out his mains power quality.

Harmonics
http://p3-inc.com/whitepapers/harmonics.pdf
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sailcappy OP
57 posts
 
"Is the breaker a GFCI (Ground Fault Circuit Interrupter) or an AFCI (Arc Fault Circuit Interrupter)? These type of breakers have a test trip push button on them."

There are no test trip buttons on any of the circuit breakers in the breaker panel.

"As for the circuit breaker used on the Cary.... Is the switch actually a breaker? The handle trips position and has to be reset? If it is indeed a breaker the more times it is tripped the weaker it becomes."

Yes it is an actual breaker as the switch has to be switched back on to put the unit back into standby. I have had it replaced to no avail.

"By chance does your friend have a clamp on amprobe so you could measure the inrush current draw of the amp on startup?
"
He did use one yesterday I have forgotten the outcome and will ask him tomorrow.

I do live in a high rise and my building said and I quote "as long as the breaker is not tripping then we do not concider you to have a problem." So much for living in a "luxury building".
sailcappy OP
57 posts
 
How do I contact Almarg?
jea48
4,425 posts
 
"Is the breaker a GFCI (Ground Fault Circuit Interrupter) or an AFCI (Arc Fault Circuit Interrupter)? These type of breakers have a test trip push button on them."

There are no test trip buttons on any of the circuit breakers in the breaker panel.
08-15-12: Sailcappy

I asked because you said the black and white wires of the branch circuit went to the breaker.
4. The White and Black wires connected to the circuit breaker seem to be 10 guage.
When a GFCI or a AFCI breaker is used both the hot conductor and the neutral conductor, of the branch circuit, terminate on the breaker. The breakers have a white pigtail that extends to the neutral bar in the panel.

http://caryaudio.com/pdfs/manuals_2012/Model7.250_manual.pdf


How do i contact almarg?
08-15-12: Sailcappy
Well under the new Agon system you can not....

All you can do is hope Al reads this thread.....
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