I need to synchronize three switches to close simultaneously (within .1 seconds) and capture the switch closing data with a time stamp upon each switch closing. Anyone know of something I can buy that will do this?

 

A 4-pole relay should do the simultaneous switching.
Do you have something to record the time-stamp?

 

A 4-pole relay should do the simultaneous switching.
Do you have something to record the time-stamp?

This is a little different application. The switch wipers are part of a three-phase MV 34.5kv / HV 161kv MOAB (Motor Operated Air Break gang switch). It's important that they close simultaneously and watching three things happening at the same time is a neat trick. The point is to make sure that no single pole picks up all the load and that the mechanical part is adjusted so that they all close in completely. Eyeballing it is a bit too subjective. I would like to record the time when each phase makes contact. I have a hokey set up that's still a little Rube Goldberg, but I thought someone on here might have a better idea.

 

This is a little different application. The switch wipers are part of a three-phase MV 34.5kv / HV 161kv MOAB (Motor Operated Air Break gang switch). It's important that they close simultaneously and watching three things happening at the same time is a neat trick. The point is to make sure that no single pole picks up all the load and that the mechanical part is adjusted so that they all close in completely. Eyeballing it is a bit too subjective. I would like to record the time when each phase makes contact. I have a hokey set up that's still a little Rube Goldberg, but I thought someone on here might have a better idea.

Thanks for your time and effort.

 

I would like to record the time when each phase makes contact.

So your question was about recording the closing times for the three contacts?
You could possibly use a USB data acquisition module for a computer (example).

Or how about a 4-channel digital scope?

 

QUESTION! Are you hoping to do this test in circuit, under load? OR in a test setup, not connected to high voltage? That makes a very big difference in the test setup. If the contacts are visible and if the test is in-circuit under load, I suggest a high speed camera, either video or film, like is used to record crash testing.

The other question is HOW ACCURATE?? What resolution??

 

The data acquisition module looks interesting. Of course the oscilloscope would be perfect, but it’s a bit more money than I think I could persuade my boss is necessarily.

once again, thank you for your generosity.

 

Of course the oscilloscope would be perfect, but it’s a bit more money than I think I could persuade my boss is necessarily.

You can get Chinese 4 channel oscilloscopes for a low as $240, which should do what you need.

 

The challenge with any signal connected scheme gets complicated when the actual conditions are known: " The switch wipers are part of a three-phase MV 34.5kv / HV 161kv ". That sort of voltage requires additional effort to handle safely. so the required scope probes will be rather special.
Probably that $240 4-channel scope's input voltage range does not go that high. AND, consider it is probably not a memory scope. AND the switch closure is not a recurring wave form.

And, aside from that, consider that the same instant that one phase of any three-phase load is connected, all three lines are "hot"!! ( By "instant" I actually mean after the time it takes the voltage to travel along the wire to the load and back thru the other wire.)

 

A better desription than " hokey set up that's still a little Rube Goldberg, " of your existing method may help us to understand your requiremnts better. I dont think many members of this forum have experience with high voltage power distribution network equipment. The most I have worked on is 415 volt three phase at less than 400 amps.
If the testing could be done using low voltage to detect the contacts closing I was thinking of reading the state of the contacts as 4 bits of a byte and logging that say every 10 mS . If you then formatted this stored data to create a text file that you could scroll through on a computer. This conversion could be done using most microcontrollers and the text data captured via a serial port on a computer.

Les.

 

The switch wipers are part of a three-phase

You DO realize that at three phase, none of the wave forms are in phase. They are 120˚ out of phase with the next. Switches that close at the exact same instance will have different loading on them. And @MisterBill2 alluded to - high voltage testing is dicey. If you were to set up a low voltage single phase or DC test you could determine the timing between the closure of the contacts. But I don't know of a situation where that kind of timing on a switch is that critical.

 

Consider that if the test were done on 60 Hz that the time for a complete cycle is about 18 milliseconds. my guess is that the accuracy needs to be in the single millisecond realm, and quite probably the resolution needs to be less than a millisecond.
So if the contacts would be visible to a fast video camera, then using the fast video scheme used for crash testing, you could get a high resolution video record of the closure actions. And if the circuit is live, then the difference should be visible. The fast video is recorded and gives millisecond resolution.