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Re: (ET) Broken Breaker



Thanks Geoff ! TI should have you do their web page!

- SteveS

Geoff Rich wrote:

It looks like TI has completely re-done the Klixon webpages.  From some 
stuff I figured out before:

P=precision  (tighter specs on temperature derating of ultimate trip point)
or
C=normal (standard temperature derating of ultimate trip point)
or
S=square/rectangular case with normal derating

D=sealed construction (has the metal backplate)
or
(no letter)=open (no backplate)

L=large frame size (as used on traction motor in E12, E15/16, E20)
or
(no letter)=small frame size (used on mower motors, & for CB2 on upper 
control panel)

A=automatic reset
or
M=manual reset (the big red button).

Amperage follows the prefix letters.

It looks like TI no longer lists the CLDA or CLA type breakers in the larger amperages;  
I guess we will now have to sub with the SLDA or PLDA instead.  SLDA should fit, since 
the bolt holes are still ~2.4" OC.  PLDA's have same exact case as the CLA's/CLDA's 
did, so they are drop-in replacements, but they might be more expensive due to their 
"precision" specs.

I wouldn't recommend the "open construction" type (SLA or PLA), as water & 
dirt could get inside the breaker.

Looking at the derating curve, I think I see why GE mounted these right on the 
motors.  At higher temperatures, they trip at less than the rated amperage.  If 
a motor's already hot, you probably don't want to make things worse by allowing 
the maximum permissible current to flow in the armature.  As anyone who has 
ever done any wire sizing knows, it's all about keeping the temperature of the 
insulation material well below the point where it starts turning into a carbon 
resistor. (For varnish, I think it's about 150-200°C?)

-Geoff


-----Original Message-----
From: SteveS [mailto:ssawtelle fcc net]
Sent: Friday, July 23, 2004 9:57 AM
To: et
Subject: Re: (ET) Broken Breaker


Thanks Tom and all,

The one I took off the E12S is a CDLA-80. which must be an 80 amp device, makes sense since it is an E15 motor. I'm not sure what the diff is between PDLA and CDLA. The 'A' means automatic reset. I think the 'L' is the basic size/style. The TI web site isn't real clear on the part number meanings.

You must be right about wanting some extra senstivity to the motor heat, because it takes a bit of extra wiring to put it there.

- SteveS




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