6 pull disconnect

[dm9289]

Where I am employed proper loto can be challenging, we have many stab shunt motors with temp protection so basically 6 wires need disconnected to change a motor

A DC drive produces armature current for A1 A2 S1 S2
A field excitor produces DC for F1 F2
Two more wires P1 P2 are related to a internal motor thermostat.

Throughout the years many adaptions have been made to this process which can make loto difficult and complicated. We have roughly 23 motors in this area and for safety and simplicity I would like to have a 1 pull disconnect that shuts off all 6 wires at the motor.

Thanks
Dave

 

[Buck Parrish]

Could you use contactors ?

 

[dm9289]

Probably but I am trying to keep expense low and not add wiring or additional code to the PLC. The MCCs are far away from the motors and it can be confusing what to shut off with 3 power sources.

 

[GoldDigger]

Probably but I am trying to keep expense low and not add wiring or additional code to the PLC. The MCCs are far away from the motors and it can be confusing what to shut off with 3 power sources.

I doubt very much that contactors driven by a PLC would qualify as a safety disconnect for doing electrical work on a motor. It would definitely not support LOTO.

Sent from my XT1585 using Tapatalk

 

[Jraef]

You can buy 6 pole disconnects, they are two x 3 pole disconnects that are ganged together. You need them for 2 speed 2 winding motors too.

Now, depending on your DC voltage, that may be another problem altogether. Most Knife Switch type disconnects are not DC rated for above 250VDC without putting poles in series, in which case you would need 12 poles! Can you disconnect the 3 phase power that feeds the DC drive instead?

If that can't work, the other possibility is to look at the power ratings you need for the circuits other than the armature, because maybe they are small enough to be run through Auxiliary contacts off of the main switch mechanism.