ALC68 checking temp.

[ronny]

Hi,

has anybody an idea or some experiences where on the head i can check the temperature. There is a sensor which will disable mains at 140°C, this sensor is located between the magnetic coils - in my mind 140° at this sensor is very heavy or?

Is there any location and perhaps a given value where i can be sure that everything is fine and my cooling is sufficient?

Im trying to be very careful to keep this tube healthy. I added a sensor directly at the location of the 140°C switch and reach ~50°C after 3mins of operation - with the lowest current i can get from an EIL4000 (9Amps? - not sure about).

Ronny

[yaddatrance]

Well 50 degrees sounds like it's running pretty cool, so if you have that, then keep on truckin'.

I'd get worried as you approach 100 degrees for obvious reasons, but 68's are known to
run pretty hot. Given adequate ventilation (and 50 degrees qualifies) the life of your tube will
be based on the amount current you run. If you idle at just enough to keep it lasing, then the
tube will last 100s of thousands of hours. If you crank it up to full power regularly, I'd give it a year...
External measurements of aren't useful beyond sanity check. And holding your hand up to
the exhaust of your 68 should work just as well. If you can't keep your hand in the exhaust, then
you'll want to back off the juice...

[dream beamz]

Is this a 68b (air cooled) or 68c (water cooled) I am assuming its the 68b since you are worried about temp

I am only familar with my old 68b in fahrenheit

My laser never got above 140 F pushing a constant watt. I measured the output ventalation temp inside the laser. I simply placed a digial pad inside the laser to read the temp

[ronny]

Its a air-cooled 68b.

140F are about 60 degree celsius.

I added sensors to the tube (and the inner copperfins).

Im not sure about my current, as said im using the lowest current from an EIL4000 psu - even it would be great if i can raise up the current to get 1W.

Im not interested to drive it full power but want to know how good my ventilation system is (its homebrew and find out a god current/temp to drive it permanently.

Ronny