Agricultural and Biosystems Engineers Licensure Examination (ABELE) · Philippines · Professional Regulatory Board of Agricultural and Biosystems Engineering, PRC
Original practice questions written to the published syllabus · not past papersAgricultural and Biosystems Engineers Licensure Examination (ABELE) is a licensing and registration exam run by Professional Regulatory Board of Agricultural and Biosystems Engineering, PRC, for candidates in Philippines. Paper-based, 2 days (Day 1 6 hours; Day 2 5 hours + 4 hours). Non-programmable calculator only; the Dec 2025 programme bans the Casio fx-991ES/ES Plus by name.
Source: prc.gov.ph.
Checked against the exam body's published information. Formats and fees change; confirm the current edition there before you book.
Power, energy and machinery paper: tractor components, power transmission calculations, PTO and hitch standards, tractor testing terms under national standards (PAES), safety.
Everything between the engine and the implement: clutch, gearbox, differential, PTO, brakes, steering, hydraulics, hitch and tyres.
Our 17 Agricultural and Biosystems Engineers Licensure Examination questions in this subject: 2 easy, 15 medium, 0 hard, across 13 units.
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
These 10 were written to Agricultural and Biosystems Engineers Licensure Examination and are not shown on any other exam's page.
A planetary final drive has an 18-tooth sun gear driven by the axle shaft, a 72-tooth ring gear fixed to the housing, and the planet carrier driving the hub. The reduction ratio is
A. 5:1
With the ring fixed, sun in and carrier out: i = 1 + Z_ring/Z_sun = 1 + 72/18 = 5. 4:1 treats it as a simple gear pair; 1.25:1 is the ratio with sun fixed and ring driving; 0.25 is inverted.
An engine delivers 200 N·m through a drive train with an overall ratio of 90:1 and a transmission efficiency of 0.85. The total torque at the rear axle is
C. 15,300 N·m
Axle torque = engine torque × overall ratio × efficiency = 200 × 90 × 0.85 = 15,300 N·m. 18,000 ignores losses; dividing by efficiency gives 21,176, more than the input can provide. 21,250 is the gross wheel force in newtons at a 0.72 m radius, not a torque.
A tractor travelling at 25 km/h brakes with a constant deceleration of 3.0 m/s². The driver's reaction time is 0.75 s. The total stopping distance is
D. 13.2 m
v = 25/3.6 = 6.94 m/s. Reaction distance = 6.94 × 0.75 = 5.21 m. Braking distance = v²/2a = 6.94²/(2 × 3.0) = 8.04 m. Total = 13.2 m. 8.0 m omits the reaction time; 104.2 m is the braking distance alone with km/h left unconverted (25²/6). 5.2 m is the reaction distance alone.
The unloaded overall diameter of a 420/85R28 tractor tyre is approximately
B. 1,425 mm
Section height = 0.85 × 420 = 357 mm. Rim diameter = 28 × 25.4 = 711.2 mm. Overall diameter ≈ rim + 2 × height = 1,425 mm. Adding only one section height gives 1,068; using section width instead of height gives 1,551; 711 mm is only the rim.
A trailed implement needs 12 kN of draft at 5 km/h. If the drawbar power available is 0.7 of PTO power on this soil, the PTO power the tractor needs is about
B. 23.8 kW
Drawbar power = D × v = 12 kN × 5.0/3.6 m/s = 16.67 kW. PTO power = 16.67/0.7 = 23.8 kW. 16.7 kW is the drawbar power only; multiplying by 0.7 goes the wrong way; not converting km/h gives 86. The drawbar/PTO ratio varies with soil and drive type, so it must come from data for the actual conditions.
Reverse in a sliding-mesh gearbox is obtained by
D. introducing an idler gear between a layshaft gear and a main-shaft gear
An idler gear adds one mesh and so reverses rotation. The idler itself does not change the ratio between the two gears it connects.
The crown wheel and pinion in a tractor rear axle perform two functions:
A. a speed reduction and a 90° change in the direction of the drive
The bevel pinion drives the crown wheel at right angles, turning the longitudinal drive into the transverse axle, and provides a reduction equal to crown-wheel teeth divided by pinion teeth.
Viewed from behind the tractor, looking at the end of the rear PTO shaft, the standard direction of rotation is
A. clockwise
PTO standards fix clockwise rotation viewed from the rear so implements from any maker turn the right way.
In an internal expanding shoe brake, the shoes are forced against the drum by
D. a cam or hydraulic wheel cylinder between the shoe ends
Internal expanding shoes pivot at one end and are pushed outward by a cam (mechanical) or wheel cylinder (hydraulic); return springs retract them.
Toe-in of tractor front wheels is adjusted by
D. changing the length of the track rod (tie rod)
Toe-in is set by lengthening or shortening the track rod and is measured between tyre centres at hub height in front of and behind the axle.
This plan follows where our questions actually fall, so the time goes where the marks are likely to be. It is our reading of the syllabus, not the exam body's weighting.
Read the manual chapters for these first and do every worked question you can find on them.
Aim for one sitting per unit, then mixed questions across them.
Learn the definitions, classifications and standard numbers; these units are more often recalled than worked.
Do these early in revision so they are fast on the day.
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