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SSRMAN-1P APPLICATION NOTE AN4


This application note relates to the SSRMAN-1P power supply quality and its effect on firing stability.

Background:  The SSRMAN-1P derives its power and synchronization from a 24VAC isolated supply.  If there is any distortion of the 24VAC sine wave this can cause the unit to misfire, especially at high output levels (>50% output).   The misfiring is evident if the RED led begins flashing erratically.  

Technical Details:  The SSRMAN-1P loads the supply transformer asymmetrically using a half wave power supply.  Some supply transformers with small cores may exhibit a magnetizing effect distortion.  The effect is multiplied as more SSRMAN-1P modules are added to a single transformer supply.  If this magnetizing distortion is present with the misfiring, there are two steps that can be taken to make the system operate correctly:

1) Change the transformer to a larger transformer.

2) If the transformer cannot be changed, employ the loading scheme as shown in the diagram below.  This will balance the transformer load and should correct the distortion and the misfiring.