John Deere models:
John Deere tractor: A, B, D, G, H, LA, M, R
John Deere tractor: 40, 50, 60, 70, 80
John Deere tractor: 320, 330
John Deere tractor: 420,430,435, 440
John Deere tractor: 520, 530
John Deere tractor: 620, 630
John Deere tractor: 720, 730
John Deere tractor: 820, 830, 850, 855
John Deere tractor: 950, 955
John Deere tractor: 1010, 1020, 1520, 1530
John Deere tractor: 2010, 2020, 2030, 2040, 2150, 2155, 2240, 2350, 2355, 2440, 2510, 2520, 2530, 2550, 2555, 2630, 2640, 2750, 2755, 2840, 2855, 2940, 2955,
John Deere tractor: 3010, 3020, 3055, 3150, 3155,
John Deere tractor: 4000, 4010, 4020, 4030, 4040, 4050, 4055, 4100, 4200, 4230, 4240, 4250, 4255, 4300, 4320, 4400, 4430, 4440, 4450, 4455, 4520, 4555, 4620, 4630, 4640, 4650, 4755, 4840, 4850, 4955,
John Deere tractor: 5010, 5020,
John Deere tractor: 6030, 6100, 6200, 6300, 6400, 6500,
John Deere tractor: 7020, 7200, 7210, 7400, 7520, 7600, 7700, 7800,
John Deere tractor: 8200, 8430, 8440, 8450, 8560, 8630, 8640, 8650, and 8760.
Hoy, Roger
Eighty-six Years and Going Strong
The Nebraska Tractor Test Laboratory (NTTL) was established in 1920 in response to the Nebraska Tractor Test Act of 1919, which required all agricultural tractors sold and advertised in Nebraska to have manufacturers' performance claims verified by the Nebraska Tractor Test Lab. The act was vigorously sponsored by W. F. Crozier (a state representative who in 1916 purchased a tractor that did not perform as advertised) and fellow senator Charles Warner.
From humble beginnings ...
The first tractor successfully tested in the lab was in 1920 - a John Deere Waterloo Boy. The original tractor test lab facility was intended to be only temporary and was erected very quickly, however, the building was used for decades. In 1980, the original tractor test lab facility - now the Lester F. Larsen Tractor Test and Power Museum - was designated an Historic Landmark of Agricultural Engineering by ASABE. (Larsen was the NTTL's longest serving director, from 1946 until his retirement in 1975.)
Over the years, changes in tractor technology and increased specialization of associated traction machinery have resulted in changes to the Tractor Test Act and corresponding alterations to the Tractor Test Lab's role.
For example, construction tractors (steel-track crawlers and loader-backhoe tractors) were exempted from test in 1956. In the 1960s, the first minimum power limit was established at 20 advertised horsepower, excluding riding lawn mowers and lawn and garden units from test and permit requirements. In 1986, the minimum horsepower level was raised to 30 kW (40 hp), due in part to the growth of tractor power away from lower levels and the advent of larger lawn and garden tractors. Also at this time, the law was changed to allow the tractor test lab to conduct tests according to the Organization for Economic Co-operation and Development (OECD) test codes. The state of Nebraska now allows OECD tests conducted elsewhere to be accepted for use in Nebraska.
... to worldwide recognition
While the law only applies to tractors sold and advertised in Nebraska, tractor users outside the state and even in other countries are effectively protected against false performance claims. There are few tractor models sold in other parts of the United States that are not also sold and advertised in Nebraska, so most farmers benefit from the lab regardless of where their tractors are purchased. The NTTL is entirely self-funded with no taxpayer dollars used to finance its operation. Tractor manufacturers pay relatively modest fees for the testing of tractors and the evaluation of OECD test reports performed elsewhere. This allows manufacturers to obtain the required permits to sell tractors in Nebraska for tractors tested in other OECD-approved test facilities. With a reputation developed over 87 years of unbiased, quality test results, the NTTL is recognized as one of the premier tractor testing laboratories in the world.
In the lab in 2007
Today, all tractors tested undergo one or more tests at the tractor test lab. Tractors have PTO horsepower verified (Figure 1). This test is more than just a verification of power; it also establishes a full load power and fuel curve and also includes partial power testing. Additionally, tractors with more than 100 PTO horsepower are tested for drawbar performance. During drawbar testing, each tractor tows a load car (Figure 2). The load car pictured on the left has been in use since the fall of 2003 and replaced the earlier load car, shown on the right, that had its origins in 1937. During testing (Figures 3 and 4, below and right), a number of measurements are made in each gear at rated engine speed and maximum power engine speed. These measurements include fuel used (which is supplied and measured from the load car), drawbar pull, speed, travel reduction (reported as slip), distance traveled, engine and fan rpm, as well as various temperatures. The load car applies a load using three electric retarders in series driven through a separate transmission. Additional load units are sometimes pulled behind the load car to provide additional loading if the tractor under test is sufficiently powerful (Figure 4).
Generally, the tests for one tractor require approximately a week. Typically, it takes one full day to conduct a PTO test, unless more time is needed for minor power adjustments. Fuel rate adjustment is allowed to ensure that: 1) the minimum advertised power at either rated engine speed or standard PTO speed is met or 2) the power does not exceed the maximum power desired by the manufacturer. The manufacturer is constrained to not exceed warranty fuel limits for the engine series in each model. Drawbar testing typically requires portions of three days to complete. Because tractor performance varies depending upon atmospheric conditions, tests must be conducted when air temperatures are above 10°C (50°F) and below 21°C (85°F). Testing may also be conducted 4°C (40°F) at the request of the manufacturer. However, tractors are only tested in the fall and spring so temperature constraints can be met. In practice, this may mean that drawbar testing must stop as the day becomes warmer. Also, barometric pressure must be above 725 mm Hg (28.53 in. Hg) for both drawbar and PTO tests. In addition to PTO and drawbar tests, sound levels, hydraulic flow, and three-point lift capacity are also tested. Nebraska Tractor Test personnel are also called upon to witness roll-over protective structure (ROPS) testing at manufacturer's facilities and to prepare OECD test reports for these tests. While not typically required in the United States, third-party-observed testing of ROPS to meet requirements of the relevant OECD codes allows these ROPS to be certified for use in many countries that require ROPS certification.
Other roles and goals
Besides fulfilling its primary role of tractor testing, the NTTL also performs other related testing such as engines using alternative fuels and market testing of non-tractor machinery such as motor graders. Further, the lab fulfills a valuable educational role by providing employment for eight to 12 students each semester. The student experiences gained at the lab, as well as through direct contact with manufacturer representatives, have enabled many secure productive careers agricultural and construction machinery manufacturers.
ASABE member Roger Hoy is director of the Nebraska Test Tractor Laboratory, Lincoln, NE
