Smartpack(s) Full at 1%

I'm not readily familiar with the innards of the smartpacks, but I've seen a similar symptom on other dimmers after someone has modified the unit from single phase to three phase or vice versa.

There are usually some sense feeds to the control electronics that are tapped off the main feeds into the dimmer (and fuse protected.) Each phase has a sense feed for 4 dimmers in a 12way pack.

If the phase is sensing on the correct phase, it will work fine.

If the phase is sensing on the incorrect phase, you can see a full at 1% scenario, because the dimmer is trying to control the output based on the wrong sensed input.   This might explain the full at 1%. This may be because someone swapped the senses for B and C, or left it set for single phase sensing while changing the feeds to 3 phase or the reverse of set for 3 phase sense, while feeding 1 phase power.

The stuck dimmer may be a bad SCR or someone has set the level at the front facepanel.  That may not be related to the phase sensing.  Can't immediately help you there.

Of course, if you are not familiar with changing the phasing of a dimmer pack, I highly suggest you call someone in who is.  Also, I highly reccomend you don't open the dimmer unless it is completely unplugged from the source power.  Just the usual suggestions to be safe.

Good luck.

I'm not readily familiar with the innards of the smartpacks, but I've seen a similar symptom on other dimmers after someone has modified the unit from single phase to three phase or vice versa.

There are usually some sense feeds to the control electronics that are tapped off the main feeds into the dimmer (and fuse protected.) Each phase has a sense feed for 4 dimmers in a 12way pack.

If the phase is sensing on the correct phase, it will work fine.

If the phase is sensing on the incorrect phase, you can see a full at 1% scenario, because the dimmer is trying to control the output based on the wrong sensed input.   This might explain the full at 1%. This may be because someone swapped the senses for B and C, or left it set for single phase sensing while changing the feeds to 3 phase or the reverse of set for 3 phase sense, while feeding 1 phase power.

The stuck dimmer may be a bad SCR or someone has set the level at the front facepanel.  That may not be related to the phase sensing.  Can't immediately help you there.

Of course, if you are not familiar with changing the phasing of a dimmer pack, I highly suggest you call someone in who is.  Also, I highly reccomend you don't open the dimmer unless it is completely unplugged from the source power.  Just the usual suggestions to be safe.

Good luck.