Now if the scope is plugged into 60 Hz and we select EXTERNAL and LINE then our trigger signal is now 60 Hz. The scope will indeed trigger, however, there is no way you will obtain a stable display with a 400 Hz. signal displayed. You will have triggering but.... NO SYNCHRONIZATION
Yes True, but why no synchronization? because the O-scope horizontal is at 60hz so it can find a start point? why can't it obtain a stable display? is it because the O-scopes horizontal beam is defaulted at 60hz right? so when you apply a 400hz SOURCE this changes the O-scopes horizontal beam to 400hz not 60hz right?
What's the difference between triggering and Sourcing?
Sourcing is the synchronization , the O scope is defaulted at 60hz, the horizontal bean circuit is going across the display at 60hz
A 60 HZ trigger signal will trigger (with sync) a 60 Hz waveform or multiple of 60 like 120 or 240 or 480 HZ. The opposite is also true. Plug the scope into 400 Hz. power and choose a line source the scope will trigger but you will not be able to synch for example a 60 Hz signal. You could synch 400, 800 1.6 KHz and so forth.
Yes True, But why is that? look deeper into why
The 60hz is like a clock signal and the 400hz is like a clock signal right? its frequency
If I brought you a circuit board and had 10 outputs waveforms and I didn't tell you what the line or sync frequency was , how would you know what to SYNC , SOURCE, TRIGGER the O -scope to?
You would first measure the frequency/time of the waveform? but how would you find out what the SYNC frequency is?
Since the O-scope is defaulted at 60hz, all the waveforms would be Free Running because you don't know what the waveforms are SYNC to.
How would you find out what the signals that are periodic with a period that is related to that SYNC frequency? the frequency/time of the waveform is not the Sync frequency
The Sync frequency is an external signal
How would you find out the external signals frequency without me tell you what is it?
I suppose it because you want to look at signals that are periodic with a period that is related to that 400 Hz.
Yes I do,
The Periodic or time period at 400hz is different than a time period at 60hz
The SYNC frequency ( external signal ) is like a clock right?
The Time and frequency of the signal can be different than the SYNC frequency ( external signal )?
The Waveform is superimposed on top of the sync frequency ( external signal ) ?
Before you go any further, find out for sure if the 400 Hz main and the 60 Hz main at your work are single phase mains that have one leg tied to ground. I know that a typical 120-volt main in the USA consists of a neutral leg that is connected to ground somewhere and a hot leg that is 120-volts with respect to that neutral. But I don't know about your 400-volt feed. It might be the same sort of thing, or it might be a floating power feed from a transformer. Until you find out for sure which it is at your work, you cannot safely connect the 400 Hz main to the EXT of the scope.
Ok this I will have to try to find out at work if they know the answer, but the 115VAC at 400hz is a 3 phase , I don't know if it's delta or WYE
The 115VAC at 400hz goes to a AC ratio step down transformer that outputs 26 VAC at 400hz , this goes to Gyros motors & Syncro motors
This is fine if the Function Generator is actually generating the same 400 Hz that is powering the 400 Hz line to the board under test. But if it is just some other 400 Hz that is not related to the 400 Hz on the board, it will not do any good, and the trigger will still appear free-running.
The function generators output is 400hz , it's the same frequency why won't it work? i don't get it?