Hello All, Here's some challenging questions:


1. Demonstrate the use of a digital storage oscilloschope to set or measure the pickup delay of a typical control relay.

2. Using a VOM or DMM, how can you make a voltage measuring device like an oscilloscope monitor a dry relay contact without fear of damaging the relay contact?

3. Deonstrate how to test pickup of a current opearted relay coil using a load box (without burning the coil up)

Why do you only apply current in short duration pulses during current pick up testing.

4. Demonstrate how to use an ohmmeter to verify the direction of wiper movement so you can make test lead connections and set the wiper to a position to energize the variac with zero output voltage.

Why do you need to fuse the AC supply to your variac?
What rating of fuse would you use for a 10 amp variac? A 3 amp variac?

5. Demonstrate how to test pickup and dropout of a voltage operated relay using a variac.

Why should you always turn your variac back to zero between and after tests?

6. Demonstrate how to do timing measurements with Dranetz polymeter, Arbiter, or equivalent. List the types of triggering signals can be used with your timing device (Vac, Vdc, dry contact, etc.)?


Thanks

 

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