Absolute Noob Emergency Stop Controller Question
Absolute Noob Emergency Stop Controller Question
(OP)
I am using an emergency stop controller. When the emergency stop control is triggered, the output from the control should open a 2 pole contactor carrying split-phase 240VAC and a 3 pole contactor carrying 3ph power. Because I cannot find an e-stop control with any pilot duty ratings (ie UL508 Axx, Bxx, Cxx) which guarantees it can drive the contactors directly, I was planning on using pilot duty relays in between the controller and the contactors. Is there any problem with this approach?--safety requirements are minimal-- ie IEC Sil Level 0). Basically the customer just wants a visible E-stop function.





RE: Absolute Noob Emergency Stop Controller Question
RE: Absolute Noob Emergency Stop Controller Question
Since I have posted this, I have done much research and learned that this approach is acceptable for some categories of protection. The universal recommendation is that any relay or contactor used to augment the voltage/current/isolation rating of the safety controller's contacts is performed with force-guided contactors or force-guided relays.
Force-guided relays/contactors cannot have any poles in a mismatched state. I am not sure what the purpose of this requirement is, if someone could treat this as my second question.
RE: Absolute Noob Emergency Stop Controller Question
RE: Absolute Noob Emergency Stop Controller Question
But I am going to use the controller because it implements e-switch contact monitoring, voltage monitoring, and manual restart with a minimum of wiring.
RE: Absolute Noob Emergency Stop Controller Question