英語翻譯
The power take-off test will be made consisting of a two hour test at the maximum power specified by the manufacture with a 20 per cent increase in torque applied every five minutes for a period not exceeding one minute.If the engine does not develop the 20 per cent increase in torque the intermittent overload shall be carried out at maximum engine torque.This fact shall be noted in the test report.In either case the maximum power take-off power reported for the two-hour test will be that specified by the manufacturer.
Non-mechanical coupling between engine and power take-off
This will be the case of a fluid or electrical power transmission system with its possible cooling component.The following test conditions and procedures shall apply.
In addition to those required under 4.1.4.1 above,a means shall be provided for measuring the temperature of any non-mechanical components which couple the engine to the power take-off system.
Test procedure
The governor control level being set for maximum power,the system shall be operated at maximum power take-off power for a period sufficient to establish stabilised conditions but not less than two hours.The power take-off system shall be considered stable when two consecutive temperature readings of the cooling device taken 10 minutes apart do not differ by more than 1度
The tractor shall then operate for a period of one hour.The maximum power quoted in the report shall be the average of minimum number of six readings to be evenly spread.If the power take-off or the engine speed deviates by more than 2 percent from the standard power take-off speed or calculated average speed respectively,the test shall be repeated.If the variation continues,the deviation shall be stated in the report.The temperature observed at the critical components of the system shall also be recorded.
A second one-hour test shall be made at the power take-off power level observed above and at the lowest engine speed which will maintain this power at the rated power take-off speed.
A third series of tests shall determine power take-off power at part loads with the governor control set as for the second test.Each test shall last at least 20 minutes and shall be made according to 4.1.1 above.
Performance at the belt or the belt pulley shaft
Test requirements
The tractor pulley shall be connected to that of the dynamometer bench by a belt.This belt shall be flexible and have appropriate power and torque transmission characteristics.Belt slip shall not exceed 2 percent and the necessary tension to obtain this condition shall be as small as possible.
The tests at the pulley shaft shall be conducted by directly coupling the tractor pulley to the dynamometer shaft.
All of the provisions for tests at the main power take-off sha apply to the belt tests and to the pulley shaft tests,with the exception of those at standard power take-off speed and for tractors unable to transmit the full engine power at the power take-off.
If the engine speed recommended by the manufacturer for tests at maximum power does not correspond to a standard belt speed,the operational characteristics of the engine at the speed corresponding to the standard belt speed shall be measured during the full load test.
Test results
The power,belt slip,hourly fuel consumption and specific fuel consumption in relation to engine speed shall be recorded,as in the main power take-off test.
Performance in a hot atmosphere
Test requirements