Quote:
Originally Posted by sphelps
Yeah I'm not sure this will make a reliable system. If the drum always moves 100% freely then it'll be fine but unfortunately my experience with OMs is they can get a little sticky under pressure and with a small amount of debris. As far as I can tell this timer works by simply energizing the motor briefly to reset the switch, the idea is this brief pulse of power will move the switch and close the circuit thus resetting it, this is an open loop control system or one without feedback. If this is the case it will work fine in ideal conditions but put it in use and you'll have nothing but problems. When the drum stops it might not start moving immediately with a big pump downstream and a few grains of sand or whatever in the drum area. The drum rotates on magnetism so it's not a direct drive so sometimes it can slip a little before being able to over power the static friction. If the drum doesn't move immediately after being energized the circuit will remain open and the counter will start again even though the drum hasn't moved to the next location. This would be the case if the switch was measuring the actual drum location. If the switch is measuring the motor shaft location then the drum could slip throwing the whole thing out of whack, ie the drum will stop at a different position.
For the system to be reliable and work in real conditions you need a closed loop control system or one with feedback. A smart relay can accomplish this and they run for around $150. You should also use two separate switches that measure the actual drum locations so the relay can distinguish between the two positions which will further enhance the reliability.
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If you have a jammed drum, then the smart motor or extra sensors will do nothing, unless they are smart enough to phone you and or take the unit apart.
When using a 2 way version the orientation of the magnet is changed deliberately so that it isn't possible to get out of whack.