SMPS800RE, low resistance where it should be inf?

waeah

Member
2014-02-07 10:00 pm
Just unpacked a new (been in its box in a couple of years) SMPS800RE from Connex.

I have mounted it in the chassis, connected earth on primary side to chassis and took some resistance measurements. (no other component connected)

Primary side: inf ohm between -v, gnd and +v
AUX1 and 2: inf ohm.

Secondary side:
Earth-ground and -v: 5k+*
Earth-ground and +v: 5k+ *
GND and -v: 2k+ *
GND and earth-ground: 4.65k (exactly)
-v and +v: 5k+

Primary earth and secondary -v: 6k+ *
Primary earth and secondary +v: 6k+ *
Primary earth and secondary earth: 4.65k (exactly)
Primary -v and secondary -v, gnd, +v: no connection
Primary +v and secondary -v, gnd and +v: no connection

* The numbers increase to about 15.5k ohm in a timeframe of 15seconds.


Is this how it is supposed to be? I was expecting to not get any resistance readings, being there should not be any measurable connection?
 
Just unpacked a new (been in its box in a couple of years) SMPS800RE from Connex.....................................

If you use PostNord it may take a while for delivery. However, "a couple of years" is in the high end.:D

* The numbers increase to about 15.5k ohm in a timeframe of 15seconds.
Is this how it is supposed to be? I was expecting to not get any resistance readings, being there should not be any measurable connection


When you get impedance readings that steadily increase for a while it is because you are charging a capacitor with your measuring current. That is no problem.
SMPS may include resistors on the secondary side that you will notice when you measure impedance on the secondary terminals.
I do not have that particular SMPS but I have spotted nothing I see as problematic.
Perhaps a set of last measurements from all primary terminals and to earth-ground. You must get "inf".
 
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