Circuit Breaker Temperature (SAL 74B)

[phax]

hi,

i have a problem with the right channel of the circuit breaker.
when i move the cutting head down in the operating position, the temperature rises up to about 75°C without sending a signal to the head.
it's just on one channel...
what could it be?

thx for the help.

[Greg Reierson]

Try calibrating the 25C setting. That's basically room temperature and where the system should sit when it's idling.

[markrob]

Hi,

If I had to guess, I would look for a flaky connection in the temperature sensing bridge. If I understood correctly, the head measures properly until it is moved. That would indicate that the bridge that senses temperature is seeing a slightly higher drive coil resistance in the down position.

Mark

[jtransition]

I would also check the wires in the pigtail connector that connects the head to the suspension box.

[Phinster]

Try turning off the amps for a few hours, see if it still does it....

[dubcutter89]

No expert on SAL74 but maybe this helps:

Have you tried measureing the head dc-resistance? Is it 4.7Ohm on both channels? Maybe it got damaged...
Have you tried what happens if you use a dummy head?
You could also pull out and interchange the Circuit Breakers - does the problem stay with the module?
Cleaning contacts (cable at amp, cable at suspension, internal contact (if there is one) in the head suspension, small cables on front to cutter)

Lukas

[jjgolden]

Hi Phax,

Did you get this one resolved?

JJG

[phax]

flo kaufmann had a look over the whole SAL yesterday.
it seemed to be a bad connection right behind the circuit breaker. it works again.
not easy to find since the machine was heavily customized back in the days..

[jjgolden]

Great to hear