Failure Of Contactors In Rev/fwd Operation

[AB2005]

Dear Friends;

 

I have been working on a “Conveyors System” project in which we have been working for installation of almost 100nos local conveyors (each conveyor will have one 1HP motor) on which we will store the sheets produced by corrugator machine. The operation of conveyors will be Rev/Fwd with a three position selector switch control.

I have faced a problem in such installation in our plant where we installed only two conveyors before corrugator for transferring the produced sheets. The operation of conveyors was Rev/Fwd. The problem was that the contactors of conveyors were stuck very frequently. I investigated that the operators turned the selector switches of conveyors (Rev/Fwd) quickly. Though we interlocked both contactors with NC contacts but due to quick transition, they stuck. We used pneumatic delay-off timers on each contactor and set 1sec time interval so if Rev contactor changed ON to OFF, the Fwd contactor could be ON after one second, thus controlled on that problem.

 

But here, we have 100 conveyors for which we require 200 timers, a lot of money. Does anyone has any other solution for that problem?

 

[yuri]

Hello.

Posistors are used for relay delays. Have been drawing diagrams for you with them - but it seems you would need also some four auxilliary contacts per each contactor.

Am not sure it would turn cheaper than the simple conventional delay relay.

Good luck.