continuity test of a motor circuit

[bluesky]

hi guys, i am asking how to test the continuity of a 3 phase socket test? just like in the 2391 practical exam, i am bit puzzled about the 3 phase circuit, shall i open the 3ph socket and isolator to test :

1: continuity between cu and isolator, 2: continuity between isolator and socket?

i know i then should add up 2 together, but the most puzzling thing is how to measure R1+R2? i have no experience of 3phase circuit

 

[pmac10]

not quite sure what youre after, if i wanted to check continuity between a 3 phase socket and a DB, i would isolate the supply at the board and connect each phase in turn (obviously the dead side of the mcb) to earth then check continuity between the relevant phase/earth at the socket in turn. id try to check earth/earth continuity first. as for r1 r2, never done it (cant even remember what its about for single phase)

 

[Steve D]

From when I did my 2391, they taught us that we need to test the entire circuit to the load size of the motor contactor/starter.

To do this, you'll need to take the top off the starter and use your pliers to turn the shaft of the isolator to turn it on.
You'll then need to push down the contactor manually (ask your assessor to push this, perfectly ok to ask) and then test L-cpc at the commando socket.

As it's a 3ph motor, you'll need to do this test 3 times, each time using a different line conductor. Although all 3 readings should be the same, use the highest reading as your R1+R2.

 

[bluesky]

From when I did my 2391, they taught us that we need to test the entire circuit to the load size of the motor contactor/starter.

To do this, you'll need to take the top off the starter and use your pliers to turn the shaft of the isolator to turn it on.
You'll then need to push down the contactor manually (ask your assessor to push this, perfectly ok to ask) and then test L-cpc at the commando socket.

As it's a 3ph motor, you'll need to do this test 3 times, each time using a different line conductor. Although all 3 readings should be the same, use the highest reading as your R1+R2.

thanks a lot steve, shall i also take the cover off the 3 phase socket? is it easy to find the cpc quickly inside?

also what is the best way to test the insulation of this circuit?

cheers

 

[Steve D]

Yes dismantle as much as you need to to get to the appropriate conductors.

Careful not to dismantle 'too much' though - you will get marked down if you take too much apart needlessly.