A
I'm using a pair of IMO MB09 mini-contactors to switch current to an 230V AC motor. The contactors have 3 NO and 1 NC contact. Contact ratings are NO: 20A; NC: 3A
Of these I'm using two NO poles on each contactor to switch the motor current (expected to be 8A when running, startup peaks not known). The rest are used as interlocks for the switching control signals, <2A @24Vdc.
My colleague has told me that this is bad practice, that the load on the contacts is "unbalanced". I tried to look this up but can find no reference anywhere. He is very experienced and I like to trust him but could anyone confirm this or point me to a text on the topic? Will they be physically degraded in some way by the variation in thermal effects? Is it some inductive thing between the poles? I am feeling a bit ignorant.
Of these I'm using two NO poles on each contactor to switch the motor current (expected to be 8A when running, startup peaks not known). The rest are used as interlocks for the switching control signals, <2A @24Vdc.
My colleague has told me that this is bad practice, that the load on the contacts is "unbalanced". I tried to look this up but can find no reference anywhere. He is very experienced and I like to trust him but could anyone confirm this or point me to a text on the topic? Will they be physically degraded in some way by the variation in thermal effects? Is it some inductive thing between the poles? I am feeling a bit ignorant.