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Monarch 10EE 1968 module. Thyratrons not balanced

L

laminar-flow

Stainless
Joined
Jan 26, 2003
Location
Pacific Northwest
When looking into a sticky anti-plugging relay, I noticed that the Thyratrons are not balanced when running low speed and also under load. One thyratron glows when the other one does not unless the load goes up. Ideas?
 
Swap the tubes and see if the problem follows the tube.
The grid of each thyratron is controlled a small center tapped xformer. (Forgot the no.) check to see if each grid is getting the same voltage.

Cheers
Tim in D
 
Be sure to mark the tubes with at least L and R on tape before removing them.

Many have put them back in the same position there were in thinking they were swapped.

Bill
 
This machine also has an issue that when it is running in reverse, and the spindle lever is moved to stop, the spindle does not react right away. There is a delay of 1 to 2 seconds before the relay opens and stops the spindle. Could this be related or give an idea of the problem? I have not switched the tubes yet.
 
laminar-flow said:
This machine also has an issue that when it is running in reverse, and the spindle lever is moved to stop, the spindle does not react right away. There is a delay of 1 to 2 seconds before the relay opens and stops the spindle. Could this be related or give an idea of the problem? I have not switched the tubes yet.
Click to expand...

I haven't seen that problem on a Modular drive but the WiaD drive will have that problem when the anti-plugging relay gets sticky (literally sticky with oxidized oil). A quick clean with solvent and a cotton bud takes care of the problem.
 
I've cleaned the contacts and the flap but didn't hose it down until just now. I'll check it later today. Any idea on the thyratrons? I'd like to exhaust simple things before swapping the thyratrons. Is it even an issue to have the thyratrons not balanced when under a light load and low rpm?
 
laminar-flow said:
I've cleaned the contacts and the flap but didn't hose it down until just now. I'll check it later today. Any idea on the thyratrons? I'd like to exhaust simple things before swapping the thyratrons. Is it even an issue to have the thyratrons not balanced when under a light load and low rpm?
Click to expand...

Swapping the thyratrons is the simple thing. If the problem moves with the tube it's the tube, if not then things get messy and difficult.

And yes, they should have a mostly equal glow under most any load.
 
Cleaned and dried the anti-plugging relay and it seems to be about the same or may have become worse. When in reverse, it stays on for 1 to 5 seconds. It is only in reverse. Forward stops instantly.

But I think I have figured it out. The reverse contactor, when on, can't be opened by pushing on it with a stick. When off, and sticking on, some pressure can open the contactor. Could it just be sticky mechanically, or could it be getting some low voltage and stay on?
 
laminar-flow said:
Update. The voltage across the reverse contactor coil, (115 ac), switches correctly. With the voltage off, the contactor stays contacted for 1 to 5 seconds. Ideas?
Click to expand...

AC? Is it really? Thot those were meant to be Dee Cee operated?

Even so, this should NOT be happening with the industrial grade contactors used in a 10EE. Or any other fair to medium goods, really.

But.. back when I had to utilize El Cheapo relays, some were TOO "El Cheapo" to have used proper alloys. Now and then, certain uses, coil core and/or moving Armature would hold residual magnetism with very similar timing to your description.

Worse with Dee Cee, of course. AC tends to randomly self-correct on the magnetism issue.

For DC activated, a capacitor in-circuit can do this also - sometimes by design - so you want to look for that, too.

Another possible is weakened spring(s) os sticky carriage/rocker/pivot?
 
A quick way to see if residual magnetism is the culpert,
Put a sheet of paper .005" thick in the magnetic loop that will prevent the armature of the relay from contacting the pole going through the coil.
Apply and remove coil voltage, Does it drop quickly?

Bill
 
Well, I hosed down the reverse contactor and let dry overnight. Today is seems normal and fixed.

So back to the Thyratrons. How even should the thyratrons be? And what would one expect to see if they were not balanced? They are not that far off. I can't seem to post the video but if anyone wants it, send me a PM.
 
laminar-flow said:
So back to the Thyratrons. How even should the thyratrons be? And what would one expect to see if they were not balanced? They are not that far off. I can't seem to post the video but if anyone wants it, send me a PM.
Click to expand...

Does the problem move with the thyratron when you swap them?
 
Yes, when the thyratrons are swapped the split goes with the corresponding thyratron. But the questions is... which thyratron is the one with the issue? The one with more glow or less.

I've had this issue before when trouble shooting high oil temp on a Piper Navajo. Everyone thought it was the gauge showing high temp that was off because when swapping the gauges, the high oil temp went with the high gauge. But before ordering a gauge, I explored further. Actually it was the low gauge that was reading low, the high gauge was correct. I found both vernatherms were failed and both engines were experiencing high oil temp. Earned my pay that day.
 
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