Published · Vili Power Solutions
Safety first
Never enter a grain bin, or reach into an auger, conveyor, or mixer, unless every motor that could move material has been locked out and tagged out and the lockout has been verified. Grain entrapment and auger injuries kill farmers every year, and a control system that "should not start" is not a lockout.
Why grain and feed systems are different
Grain handling and feed processing put large motors to work in an environment most electrical equipment is not built for. Two things set it apart.
- Combustible dust. Fine grain and feed dust can ignite. Settled on a hot motor it can smolder; suspended in the air of a leg, a mill, or an enclosed conveyor it can explode. The electrical code treats areas with combustible dust as hazardous (classified) locations, and the wiring and equipment there have to be built so they cannot ignite it.
- Heavy, uneven loads. Augers, legs, and mixers start under load, jam, and run for long hours at harvest. Motor protection and controls have to handle that without nuisance trips or, worse, without tripping when they should.
Equipment that belongs in dusty areas
- Enclosures rated for the location. Motors, switches, starters, and lights in dusty areas need enclosures that keep dust out or that are designed so that an internal spark cannot ignite dust outside. An ordinary open motor or an indoor-type switch box does not qualify.
- Sealed wiring methods. Conduit and fittings that keep dust from traveling through the raceway into enclosures.
- Lighting designed for dust, with fixtures that keep their surface temperatures below what settled dust can tolerate.
- Housekeeping as part of the design. Even the right equipment needs the dust cleaned off it. A layer of dust insulates a motor and makes it run hotter.
Whether a particular area counts as classified, and which class and division apply, depends on how much dust is present and how often. It is a judgment that should be made deliberately, ideally with the facility's insurer, rather than inherited from whatever was installed before.
Motors, protection, and controls
- Aeration fans. Bin fans run for days at a time. Correct overload settings, good connections, and weatherproof disconnects at each fan keep them running through drying season.
- Augers and conveyors. Plugged-spout and jam conditions cause overloads. Protection should trip the motor before it damages itself or the drive, and the cause should be cleared before restarting.
- Bucket elevators. Monitoring for belt slip and misalignment catches the conditions that create heat and friction in the leg.
- Interlocks and sequencing. Downstream equipment starts first and stops last, so material does not pile up and choke a conveyor. Control panels with simple PLC logic make that automatic.
- Bin monitoring. Temperature and moisture cables, level sensors, and fan controls that run aeration on schedule or by conditions instead of by hand.
- Drives where they help. Variable frequency drives give soft starts on heavy loads and control speed on fans and conveyors, but they belong in a clean, ventilated location, not out in the dust.
Lockout that actually works
Every motor that can move material into or out of a bin needs a disconnect that can be locked in the off position and that is located where the person going in can see and control it. Label each disconnect with what it feeds. If an auger is controlled from a panel in another building, the lockout point has to be clear enough that nobody can guess wrong.
Warning signs
- Motors that are hot to the touch, caked with dust, or tripping more than they used to.
- Damaged conduit, open junction boxes, or cords run to temporary equipment that became permanent.
- Rodent damage to wiring around bins and feed storage.
- Disconnects that are missing, unlabeled, or cannot be locked.
Where we come in
We wire new bins and aeration fans, rebuild feed-mill and auger controls, add lockable disconnects, and bring dusty areas up to the equipment they need, for farms and dairies across Weld and Larimer counties. See our dairy and agricultural electrical and PLC and controls pages, contact us, or call (970) 685-2068.
