AE Dial: Adjusting Governor Speed and Break/Make Ratio

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Working with AE and WE dials, I've noticed that while WE dials are usually close to a 60/40 Break Make ratio, AE Dials usually seem to be in the 63-65 to 37-35 range. If so, it probably has something to do with a difference Central Office equipment, what the CO is looking for in the way of a Break/Make ratio.

WE specs I've found say the desired B/M ratio is 60/40 plus or minus 5. That would be 55/45 to 65/35.

The B/M ratio for both WE and AE dials has nothing to do with dial speed. The hardware that causes the B/M ratio is independent of dial speed, it's a ratio.

Started to work on a slow AE dial, about 7.5 PPS, that had a 65/35 B/M ratio. I'm sure the speed will increase with proper cleaning and lubrication but the B/M ratio will remain the same.

I've found that a 63/37 BM ratio works fine on POTS lines but having a dial come in 65/35 is too close to the edge of possibly not working, becoming intermittent when dialing (sometimes it dials out, sometimes it does not) and I don't want to sell a "working" phone to an eBay buyer that may not dial well in the future.

This is the subject AE dial. Looks clean but is slow probably due to a lack of lubrication, the oil dried up over decades in storage.



The Break/Make ratio can be adjusted. In this image, the pulsing leaf is shown with a red line across it. This is the where the bend to adjust must take place. The leaf to the right of the red line has the contact point. The pulsing bend to the left of the red line is what is moved by the red phenolic oblong disk which pushes on the bottom of the bend to open and close the pulsing contacts.



The adjustment is made by securely holding the leaf at the red line and bending the pulse bend. By bending the pulse bend up (the bend must take place to the left of the red line, not bending the "v" itself) will decrease the Break part of the B/M ratio, and by simple math, increase the Make part of the ratio.

IT IS IMPORTANT TO BEND JUST A BIT AND RETEST TO SEE IF THE LEAF'S SPRING METAL WAS ACTUALLY BENT.

Bend a bit and test to see if the B/M ratio was adjusted. If not or not enough, bend it a bit more. It'sa bit difficult to bend spring steel in that the bending force must be enough to affect the spring steel leaf which means the leaf will naturally spring a bit before it reaches a permanent bend and then relax when the bending adjustment is completed. It's a trial and error process.

After each bending attempt, the dial must be tested to determine the post bend B/M ratio.

I was able to adjust this dial from 65.3/34.7 to 60.3/39.7.

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As for this dial's speed, I will clean and lube the dial first and after doing so, check the dial speed. If the speed is not close to 10 PPS, the governor speed adjustment to increase of decrease the speed will be done by bending the 2 leaf springs seen inside the blue circle.



The ends of these leaves have attached to them what looks like a small half rubber ball. These are the parts that rub on the inside of the governor raceway to control the governor speed, the dial speed.

The center shaft rotating inside the raceway is shown with a red line down its middle. The shaft has a bearing point inside the raceway and in the dial frame at its other end.

To increase the governor (dial) speed, the leaves must be slightly bent TOWARD the shaft (the red line). This causes the rubber "brakes" being pushed against the raceway through centrifugal force to be less and the governor to turn faster, to increase the dial speed.

To decrease the governor (dial) speed, the leaves must be slightly bent AWAY the shaft (the red line). This causes the rubber "brakes" being pushed against the raceway through centrifugal force to be more and the governor to turn slower, to decrease the dial speed.

Bending the governor leaves is a bit tricky but I've found using 2 small flat bladed screwdrivers next to each other on each side of a leaf will bend the leaf. Again, just bend them a bit and retest the dial speed to see if changed the dial speed. It is possible to go from 13 PPS to 7 PPS in one bend, which would require an opposite bend to get it back to near 10 PPS. This can be a tedious process requiring anywhere from 1 (one - got really lucky) to 10 or so adjustments to get it near 10 PPS.


Or, if not into doing it yourself, just send it to Steve Hilsz. And, at least after reading this topic, you will know what he did to your dial.

[5415551212]

Good info and very interesting, I have never messed around much dials other than re-lubricating them. I'd be hesitant to be bending the spring steel.
What do you use to test the ratio? An oscilloscope or a tester of some sort?

[TelePlay]

I've only ever used Audacity, an Excel spreadsheet, 2 clip leads, a $5 External USB Sound Card and a laptop.

https://www.classicrotaryphones.com/forum/index.php?topic=17011.msg259593#msg259593

There of a lot of stuff posted on the forum about different ways to test disk speed and the B/M ratio and in one of those topics I confirmed my setup was as good as, if not better, using a BK-1050 analyzer, or the better Sage 930.

https://www.classicrotaryphones.com/forum/index.php?topic=17011.msg214159#msg214159

I can hook up the clip leads to the pulsing terminals on an extracted dial or connect the clip leads to the line cord to test the dial on a buttoned up phone.

[TelePlay]

I'd be hesitant to be bending the spring steel.

It's not really bending spring steel, it's just "influencing" it one way or the other.

There is no way to measure the amount of "influence" being put into the spring steel until it is measured in use after adding a bit of influence.

And if a part becomes over "influenced," the part can  be adjusted back to reduce the excess adjustment.

The necessary movement to adjust a spring steel part in a phone is so small there is no way the slight bending could ever get close to damaging the part.

[TelePlay]

With respect to the AE dial governor, upon first looking at the back of the slow dial, one can pretty much know what's wrong, why the dial is slow.

The dial on the left as found is slow at 7.5 PPS.

The dial on the right would not dial easily and would not return, a 0.0 PPS.

I didn't take a picture of the dial on the right before cleaning it but it was obviously over oiled over time. There was so much excess oil on the parts that dust collected in it making all of the moving parts "fuzzy."

The dial on the left has been tested but not cleaned. You can see some crud on the governor shaft but other than that the dial is quite clean, just has a slow dial speed. There is no crud build up on the worm drive shaft and gear.

The dial on the left is slow because its lubrication has dried out, needs fresh oil. I can tell this by having both a slow dialing speed and looking at the two fly wings attached to the governor shaft. Both are perfectly straight, have never been field adjusted, are not bent. No attempt to speed up the dial by bending them inward, toward the shaft, was attempted.

The dial on the right was slow because dust and dirt accumulated on over oiled parts and turned to a hard mud or clay over time. This dial, as it slowed in service, was field serviced by adding more oil and bending the fly wings inward to speed up the dial. The fly wings inside the red circle show the speed was adjusted by bending the wings inward at least one and probably two or three times. Just by observation alone, it was obvious that this dial became non-functional due to crud buildup and one properly cleaned and lubricated, the adjustment to the fly wings would cause the dial to run fast, in this case about 13.5 PPS. After cleaning and fresh lubrication, the wings were bent away from the shaft increasing the friction inside the raceway during operation and slowing the dial down. As shown in the image on the right, the cleaned and adjusted dial as running about 10.3 PPS.

The dial on the left may come up to proper speed just by oiling the bearing points. Oiling the bearing points and the gear teeth, operating it a few time, letting it sit, operating it again and testing the dial speed. But since the dial is out of the case, I will disassemble the dial, totally clean it and properly lubricate it during assembly. I suspect it will have and in spec dialing speed after doing that.

So, 2 problems causing a slow speed: 1) the dial on the left is dry and 2) the dial on the right was over oiled causing extensive crud build up.

[TelePlay]

This will be helpful to anyone wanting to adjust the speed of an AE dial, of this type.

This image is the flywing part of an AE dial governor assembly. As the shaft is turned by the dial's mainspring, the wings spread out due to centrifugal force. In doing so, the brake pads begin to rub on the inside of the governor raceway. The pads and raceway should be free of oil at all times.

The closer the brake pads are to the governor raceway, the slower the dial speed (takes less centrifugal force for the contact to be made). Bending the wings outward decreases the governor speed.

The farther the brake pads are to raceway, the faster the dial speed (take more centrifugal force for the contact to be made). Bending the wings inward increases up the governor speed.

If the bending is done in the red box area, a single adjustment will significantly change the dial speed, 1 to 3 PPS. Doesn't take much force in this area to have a large speed adjustment.

If the bending is done in the yellow box area, a single adjustment will be more of a fine tuning and change the dial speed in the 0.0 to 0.5 PPS. Takes a bit more force in this area to make a small change in the dial's speed.

The red bending area is a macro adjustment in that the bending force affects the right angle bend in the flywing whereas the yellow area bending force affects only flat spring metal.

These are trial and error adjustments. If over adjusted, simply bend the flywings in the opposite direction of the last adjustment. The dial speed should be checked after each adjustment until the dial speed comes into spec.