6.4 Acceleration Test
6.4.1 Procedure
6.4.1.1 The purpose of this test is to determine the acceleration performance of the fan. It measures the fans ability to obtain a desired air flow rate with a given power input.
6.4.1.2 The fan shall be mounted in an insulated test chamber as described in Clause 4.
6.4.1.3 The noise level in the test room should not exceed the level of 45 dB(A).
6.4.1.4 The fan shall be operated at constant speed and with the air inlet and outlet dampers adjusted to maintain the desired pressure difference across the fan.
6.4.1.5 The power sensor shall be mounted in the test chamber adjacent to the fans power input connection.
6.4.1.6 The data acquisition system shall be programmed to record the power input and the air flow rate at predetermined time intervals.
6.4.2 Test Conditions
6.4.2.1 The fan shall be tested under the following conditions:
a) Temperature of the test chamber: 25±2°C;
b) Relative humidity of the test chamber: 40-60%;
c) Air velocity of the air inlet: 0.25 m/s;
d) Pressure difference across the fan: 70 Pa;
e) Voltage: 230 volts;
f) Frequency: 50 Hz.
6.4.3 Test Sequence
6.4.3.1 The fan shall be set to 0.7 revolutions per second for a duration of 10 minutes. The power input and the air flow rate shall be recorded at intervals of 1 minute.
6.4.3.2 The acceleration test shall begin after 10 minutes at 0.7 revolutions per second with a sudden increase in the fan speed to 3.0 revolutions per second.
6.4.3.3 The fan speed shall be decreased in 0.2 rps increments to 1.2 rps for a duration of 3 minutes at each speed before the next speed increase.
6.4.3.4 After 1.2 revolutions per second, the speed shall be increased again in 0.2 rps increments to 3.0 rps and the fan shall be held steady for 2 minutes at each speed before the next speed increase.
6.4.3.5 After 3.0 revolutions per second, the speed shall be decreased in 0.2 rps increments to 0.7 rps and the acceleration test shall be completed.
6.4.3.6 During the acceleration test, the pressure difference across the fan shall be kept constant.
6.4.4 Test Results
6.4.4.1 The test results shall include the power input and the air flow rate at each speed increment as well as the acceleration time of the fan from 0.7 to 3.0 revolutions per second.
6.4.4.2 The data acquisition system shall also record any excessive start-up noise or vibration that occurs during the test.
