Gate Maintenance Flashcards
TT2, Gate 21, was worked on in graveyard shift. The bucket was messed with, as well as the e300. Why is it faulting? What are the diagnostic steps?
A possible solution seeking procedure looks as follows:
1) Go to TT2 (have 20 deselect conveyors that are unsafe; don’t lockout as trouble shooting).
2) find the local control panel for the gate. Put the gate into local. Try moving it from one way to the other.
3) no movement? Perhaps try a reversal of direction as it was being messed with on graveyard shift.
4) if that works, great.
But what if it’s faulting again as it rotates?
1) have the technologist look at current. If current looks okay, but the e300 keeps faulting, and it’s not tripping on an overload, BUT if the e300 is not the correct type for the load, the current sensing mechanism may be causing issues. (It can cause tripping on overload via higher amplification, though in this case it wasn’t, or it can even see too little current due to its scale, causing issues that way too).
2) solution in this case was to bypass the problem issues with the e300 (it wasn’t tripping on OL, but we did bypass the OL to solve the issue).
How does the gate know where it is in space?
The gate has a gearbox upon which it is fixed. The gearbox turns, turning with it the actual gate (the gate is a funnel, really, going to various chutes).
The gearbox has a fin attached, which aligns itself over proxes that correspond to certain positions. For instance, there are usually three proxes, and the fin, if over a prox at 0 degrees, usually means the gate is at 180 degrees, completely opposite the prox.
There is also an encoder which tells
Position (this usually calibrates at 90 degrees, after waiting there for 60 seconds; this can be accomplished in local mode).
0 degrees means the gate is facing south, funneling coal into the south facing direction. North facing is 180 degrees (north facing would mean the gate is facing north and thus in the position closest to the management building).