Billy Mayo
Member
Since the channels aren't isolated, is this dangerous apply a mains 115vac 400hz mains wall line into the channel?
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If a circuit is triggered by an event, input voltage or current, my manager said I have to use a storage o-scope because the circuit is triggered by an event is this true cant use a non- storage scope?
Since the channels aren't isolated, is this dangerous apply a mains 115vac 400hz mains wall line into the channel?
Should I use an isolation transformer to be safe?
the 115vac 400hz comes from a 3 phase main
My guess is you are involved with Laboratory / Production Test type 3 phase supplies that convert 120 or 240 VAC 60 Hz. to 3 phase 120 Volt 400 Hz
I commonly used 4 channel scopes but also using special differential input modules on my scope channels.
Why do you think it is important to know which phase a wall plug is feed from? I can't think of any single phase load that it would matter to. And any multiphase load will have all of it's feed wires in the same connector.My Manager just said to me , if you have a 3 phase main output, how do you know which wall outlet is phase A , which wall outlet is phase B, which wall outlet is phase C ?
How do you find out which Phase is which? A, B or C ?
But what are these differential input modules for oscilloscopes?
Why do you think it is important to know? I can't think of any single phase load that it would matter to. And any multiphase load will have all of it's feed wires in the same connector.
differential input modules for oscilloscopes?
My Manager just said to me , if you have a 3 phase main output, how do you know which wall outlet is phase A , which wall outlet is phase B, which wall outlet is phase C ?
If you re using just a single channel let the scope trigger off the channel you are using.
My manger said that not all phases have the same voltage amplitude, because each one is being loaded down differently in the building
My O scope is plugged into the 120vac 60hz, I won't let me SYNC up to the 120VAC 400hz , to make measurements on AC waveforms , they look like free running waveforms because the oscilloscope is not SYNCed up to the 120vac 400hz
Then someones engineering for load balancing sucks! Load balancing is a prime consideration in any 3 phase distribution be it 60 Hz or 400 Hz. Good power distribution from the sub or point of origin monitors the loads by phase constantly.
Finally and again is this 3 phase delta or wye?
If it is free running then it isn't triggered.
Run a signal into channel 1. Tell the scope to auto trigger off channel 1. The fact the scope is powered from 120 VAC 60 Hz. means nothing unless Line trigger is selected.
If the scope trigger selector has a "AC line" option, you cannot use it because, as you said, it is only for triggering with 60 Hz.
If you need to trigger to the same 400 Hz that is powering the boards under test, then connect whatever signal you have that is synchronous with that 400 Hz power to the EXT input and select "EXT Trigger" in your trigger selector.
If the only signal you can find that is synchronous with that 400 Hz is the actual 120-volt power itself, check your scope's EXT input voltage rating to make sure the 120 volts is not too high. If it is you will have to reduce the voltage with a transformer or something.
I think a bigger problem is safety when working with power like this. If you are scoping signals that are tied to the 400 Hz power supply, you should make sure the chassis of your scope is grounded so that a ground lead from your scope doesn't make your entire scope "hot" with 400 Hz power.
Any reason why the O-scope can trigger , because of why? the waveforms are Free running when they aren't in SYNC with the 400hz
The O-scope and the circuit board under test have to MATCH the same MAIN Lines that you plug into the wall?
No it does not! The only time that would apply is if the scope is setup for Line Triggering where the scope uses its line frequency for the trigger source. Assuming Internal triggering the scope can trigger from any source you select. You have things like SOURCE and MODE for triggering. Again, you are not understanding how triggering on a scope works or how to apply it.
Yes I did this and it works, but what is this Called when you SYNC the o scope to a different main line frequency? because it's not sync to 60hz it's sync to 400hz
There is no different main line frequency. There is only one mains line frequency and that is the scope's mains power line frequency. You really need to work on your terminology. The scope triggers from a SOURCE, the user determines the source.
All scope triggering needs a source.
YES! The trigger source!
True you do have to use a AC Step down ratio transformer
Depends on the scope.
Yes what is a good AC isolation transformers for O-scopes?
Again, it depends on the scope as well as the signal, there is no ne size fits all.
Would I need an AC 115v 400hz Isolation transformer? for my O scope?
Do you mean to power the scope? I have no clue what you mean with that statement.
My Manager said that when you put your DVM fluke meter to the main wall output how to you know if it's phase A,B or C?
I'm guessing you can't be plugging in different test equipment using the same phase or different phases, or it will cause loading problems or other problems?
The scope triggers from a SOURCE, the user determines the source.