Need help on wiring diagram with relay circuit

Reloadron

Joined Jan 15, 2015
5,934
Q2 looks to be an open collector NPN output placing the relay coil at a logic low when active. This energizes the relay. The diode across the relay coil acts as a flyback diode suppressing the inductive kick when power is removed from the relay coil and the field collapses. The RC network across the relay coil acts as a snubber lending me to believe the relay contacts switch an AC inductive load. Overall a pretty straight forward circuit.

Ron
 

MaxHeadRoom

Joined Jul 18, 2013
23,084
Appears to be a small DIY CNC system, that could be a relay contact for use in the E-Stop string normally used N.C. for a NAND function.
Max.
 

MaxHeadRoom

Joined Jul 18, 2013
23,084
The capacitor and resistor combo is called a Snubber, in the diagram, it goes across the relay N.O. contacts.
What is it switching?
Max.
 

MaxHeadRoom

Joined Jul 18, 2013
23,084
Is this an MB2 system?
If so, it just looks as though this is a typical connection for the outputs, and appears this is just an example of a typical output usage and thus if not switching an inductive load with the relay, the R/C snubber is not really required.
Also in the case of the MB2, I believe they are opto coupler outputs and in some cases may not require a relay, i.e. DIR input to a VFD etc.
Max.
 

Thread Starter

Ztiano

Joined Jan 23, 2021
7
Is this an MB2 system?
If so, it just looks as though this is a typical connection for the outputs, and appears this is just an example of a typical output usage and thus if not switching an inductive load with the relay, the R/C snubber is not really required.
Also in the case of the MB2, I believe they are opto coupler outputs and in some cases may not require a relay, i.e. DIR input to a VFD etc.
Max.
That relay is used to switch on the spindle of the cnc.
 
Top