WE #5H Dial Break/Make Adjustment

[TelePlay]

This dial is a bit easier to adjust than the #6 in that a fairly solid leaf must me moved a little bit to change the Break/Make ratio of a dial. Nothing has to be done to any parts of the thin leafs.

The thin pulse leaves are indicated by the green and red lines. The pulse contact by the blue arrow.

The white circle is the dial's pulse pawl which when rotating hits the longer red leaf forcing it down or away from the green leaf. This opens or breaks the circuit.

The solid leaf indicated by the yellow line determines the ratio. It determines when the break occurs by stopping the green leaf from following the yellow leaf. If a dial has a 70/30 Break/Make ratio, the solid leaf needs to be "bent" a bit downward. This increased the time the two leaves are in contact (the make part of the ratio) and reduces the amount of time the circuit is broken (the break part of the ratio).

If bending the solid leaf downward, if bent too much, the contracts will never part, will stay in the "make" mode. Simply bent the solid lead upward to allow the two leaves to separate, to break the circuit.

CAUTION: do a small bend (a 5° to 10° bend is about enough to put enough stress into the "yellow" solid leaf to cause it to be moved just a bit - the solid leaf will "spring back" to what will appear to be an unbent position, doesn't take much permanent movement to adjust the break/make ratio) and test the dial to see if the BM ratio has changed. If the 70% break break decreases to say 65, bend it a bit again. When it gets within the 60-62 range, the dial is in spec. If bending caused the break to decrease to 55% or lower, bend it back the other way to move the break time closer to 60.

CAUTION: You will not see the bend you are making. The solid metal spring steel will spring back to some position. That is why it is best to put a small bend into the "yellow" leaf and testing its B/M ratio to decide what "bend" adjustment to make next.

It is possible that the bend may put the "yellow" leaf into a position that leaves the green and blue leaves in a constant contact situation. If so, simply bend the "yellow" wing back (in the opposite direction from the last bend) a bit until the leaves once again open and close. The test the dial for its current B/M ration and if not close to 60/40, try another bend.

CAUTION: Take care when bending the "yellow" solid leaf so as not to change any other parts of the dial. This is a hit or miss adjustment but the Break/Make ratio of a #5 dial can be changed to bring an out of spec dial back into the 55 to 65 BSP break preference.

I just adjusted one from 70/30 to 62/38 in 3 "bends" so I know it can be done.

Or, just send the dial to Steve Hilsz.

[dsk]

Nice description!

For my equipment the make break ratio has been accepted in a pretty wide range, and I have stopped tuning that until it is a problem.

The British break of 2/3 (ca 68%) and the German 60% + a range of acceptance of un-tuned ratio makes the acceptance of old exchange equipment pretty wide.  My 1946 exchange accepts at least breaks between 50 and 80%, and so does my Dialgizmo. 

My goal when tuning is to be within 60-67% and thtat has worked out well even with ATA's that accepts rotary.

The dial speed may be another issue.  Some dial slows down in the end, and then the pulse lengths will not be equal.  An even speed, within  9-12 pps seems to be OK for my equipment. 

What made me interested in this was the first phone I got with a last long pulse.  A special dial for Oslo's first rotary exchange made by Western Electric. 0=9 short, and one long pulse. 

More about that in this thread: https://www.classicrotaryphones.com/forum/index.php?topic=24234.msg264466#msg264466

[HarrySmith]

Nice. Thanks for the detailed instructions. I may try to tackle a dial one day. For now I just follow the last sentence in your post.

[TelePlay]

Referring to dsk's reply, the dial speed has no relationship to the break/make ratio.

A dial running at 12 pps will have the same ratio if the speed of that dial is reduced to 8 pps.

However, the actual time length of the break and make will be affected by the dial speed. Shorter in a fast dial, longer in a slow dial.

The speed and the ratio together determine what the pulses look like to the central office equipment.

The perfect WE case is a 10 pps speed with a 60% break and 40% make ratio. A perfectly set dial will have the central office seeing a 0.06 second break in the circuit followed by a 0.04 make.

The 0.06 and 0.04 ratio time periods will  decrease proportionately for a fast dial speed, and increase for a slower dial speed.

The perfect 0.06 second plus 0.04 second would be 0.1 second per number dialed or 1 second when dialing "0", known as 10 pulses per second.

A "working" dial is one that is recognized by the central office, which appears to vary country by country.

[countryman]

Specially on ATA or VOIP equipment made by AVM and distributed in parts of Europe under the Fritz!Box brand, it has been found that any break longer than 60 ms will be recognized as a flash signal.
Making the dial faster is sometimes recommended as a remedy, but does not always help. Thorough cleaning of the mechanism and the contacts plus correct adjustment often does.

[TelePlay]

Of the few dozen dials that I have cleaned and/ adjusted (most WE but also AE and SC), I've never found one with the break ratio below 60%.

I've always wondered why some were set to 64% to 70%. Dials were always close to 10 pps but the break was too high on some.

I wonder if the US central offices had or looked at or handled a "flash" signal differently since the range I've seen has been 61 to 70 ms with the speed close to 10 pps.

I don't know. I just adjust out of spec dials to about 10 pps with a 60 to 63% break ratio.

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As for the dial speed, the following images show the way the speed is adjusted on #2, #4 and #5 dials.