Red Seal Agricultural Equipment Technician key terms

A documented procedure for isolating all energy sources on a machine, applying personal locks and tags, and proving the isolation before anyone works on or near the equipment.

Energy held in a machine after shutdown, such as hydraulic pressure, suspended loads, spring tension, or charged capacitors, which must be relieved or restrained before work begins.

A systematic visual and hands-on inspection of a machine before operation, checking fluid levels, guards, tires, belts, hoses, and safety devices to catch faults before they cause breakdowns or injury.

A reinforced frame or cab that protects the operator if a machine overturns; it only performs as designed when the seat belt is worn and the structure is undamaged and correctly mounted.

The guard covering the tractor power take-off stub and the joint where an implement driveline attaches, preventing entanglement with rotating shafting and universal joints.

A precision measuring tool using a calibrated screw and spindle to measure outside or inside dimensions to thousandths of an inch or hundredths of a millimetre, with a friction or ratchet thimble for consistent feel.

A gauge with a spring-loaded plunger and needle dial used with a magnetic base to measure small linear movement, runout, end play, and shaft deflection against a reference surface.

A set of thin, marked metal leaves used to check clearances such as valve lash, spark plug gaps, and bearing end play by finding the leaf thickness that just fits the gap.

A wrench that indicates applied twisting force so fasteners can be tightened to a specification; it must be stored at its lowest setting and calibrated periodically to stay accurate.

A standard line drawing convention that shows a component's function and connections, such as a circle with a triangle for a pump or a square with an arrow for a flow control valve.

The relationship stating that voltage equals current multiplied by resistance (E = I × R); it lets a technician predict circuit behaviour and diagnose excessive resistance or unintended current draw.

A live measurement of the difference in voltage across a conductor or connection while current flows, revealing high resistance in cables, grounds, or switches without disconnecting the circuit.

A two-wire serial network that lets controllers on a machine exchange data; faults such as a shorted or open data line can disable multiple systems at once.

A computer module that reads sensor inputs, runs control logic, and commands outputs such as injectors, valves, or relays; it stores diagnostic trouble codes for retrieval with a scan tool.

An alphanumeric code stored by a controller when a monitored circuit or value falls outside expected limits, giving a starting point for testing rather than a final diagnosis.

Current that continues to flow from the battery after the key is off, often from a stuck relay or faulty module, causing repeated no-start complaints; measured in milliamps with a meter in series.

A hydraulic component holding fluid under gas pressure to absorb shock, store energy, or supplement pump flow; its precharge must be released before any service work.

A valve that opens to route excess flow to tank when circuit pressure reaches a set limit, protecting components from overpressure and defining the system's maximum working pressure.

A system in which the pump adjusts displacement to match only the flow and pressure the active circuit demands, reducing heat and power loss compared with fixed-displacement systems.

A diagnostic procedure connecting a calibrated gauge to a test port to compare measured pressure against specification at defined operating conditions, isolating pump, valve, or actuator faults.

A gear arrangement of a sun gear, planet carrier, and ring gear that provides large speed reduction and torque multiplication in a compact package, common in final drives and powershift transmissions.

A stack of alternating friction and steel plates engaged by hydraulic pressure or springs to connect or release a shaft inside a transmission, allowing shifting under load without interrupting power.

A transmission that changes gear ratios under load by applying and releasing hydraulic clutch packs, giving smooth shifts without clutching or stopping the machine.

A mechanism that mechanically ties the two wheels of an axle together so both turn at the same speed, improving traction when one wheel loses grip; it must be disengaged for turns.

A removable cylinder liner whose outer surface contacts engine coolant directly, sealed at top and bottom by O-rings; pitting or cavitation on the outer wall can leak coolant into the oil.

The clearance between the rocker arm and valve stem tip on a mechanical valvetrain, set to specification so valves fully close when hot and open correctly without excessive noise or wear.

The amount the top of a liner stands above the block deck, measured with a dial indicator and straightedge; incorrect protrusion causes head gasket failure or liner cracking.

The pressure above atmospheric delivered by the turbocharger into the intake manifold; low boost can result from leaks, a sticking wastegate, or a restricted exhaust.

A system that routes a controlled portion of exhaust back into the intake to lower combustion temperature and reduce nitrogen oxide formation; cooler and valve faults cause rough running and codes.

The process of removing refrigerant from a system into a recovery cylinder using approved equipment rather than venting it to atmosphere, as required by environmental regulations.

The temperature of refrigerant vapour above its saturation temperature at a given pressure; measuring it at the evaporator outlet confirms correct charge and expansion valve operation.

Pulling a deep vacuum on a sealed refrigeration circuit to remove air and moisture before charging; a vacuum that will not hold indicates a leak or trapped moisture.

The ability of a row unit's meter to release one seed at a time at even spacing, measured as singulation percentage; poor singulation causes skips and doubles that reduce yield.

A metering system that holds seeds against holes in a rotating disc using vacuum and releases them at a singulating point, with vacuum level and disc selection matched to seed size and population.

The vertical load applied to a row unit to keep it at seed depth; too little causes shallow, uneven placement, while too much compacts soil and restricts emergence.

The distance below the soil surface where seed is deposited, set by gauge wheels and closing system and critical for uniform emergence, moisture access, and consistent maturity.

The gap between the threshing cylinder or rotor and the concave grate, adjusted to suit crop type and condition; too tight causes cracking and loss, too loose leaves grain in the straw.

The rotational speed of the threshing cylinder or rotor, set according to crop and moisture; excessive speed damages grain and increases power demand while too low speed leaves unthreshed heads.

Grain carried out the back of a combine with the straw because it was not separated from the material other than grain; it is checked by catching and counting grain behind the machine.

The volume a nozzle delivers per minute at a stated pressure; tip size, pressure, and speed together set application rate, and worn tips cause uneven coverage and over-application.

The amount of product applied per unit area, calculated from nozzle flow, boom width, and travel speed; it must be verified with a calibration check before treating a field.

The distance between spray nozzles along the boom, which together with spray angle and height determines overlap and pattern uniformity across the swath.

Real-time kinematic GPS correction delivered from a base station or network that gives centimetre-level position accuracy, enabling repeatable auto-steer passes and section control.

An automated guidance system that steers the machine along defined passes using GNSS position and a correction signal, reducing overlap and operator fatigue on broadacre operations.

Automatic switching of individual boom or seeding sections on and off based on mapped coverage, preventing double application in headlands and overlaps.

A standardized communication protocol (ISO 11783) that lets displays, implements, and controllers from different manufacturers work together over the machine's network.

A heat exchanger that cools compressed intake air after the turbocharger, increasing air density for more complete combustion and lower exhaust emissions.