Method and apparatus for determining fan bearing friction
First Claim
1. A fan test system for measuring the bearing friction of a fan receiving power from a power source during normal operation, comprising:
- a switch for coupling between the fan and the power source;
a current limiter coupled in parallel with said switch;
a power controller coupled to said switch to test the fan by controlling said switch to interrupt power to the fan for at least a predetermined time period; and
a measuring device coupled to said current limiter for detecting voltage pulses of the fan to determine a spin-down rate value during said predetermined time period indicative of the bearing friction of the fan.
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Accused Products
Abstract
A fan test system and method for determining fan bearing friction and available life, including a power controller for changing the fan'"'"'s power level for at least a predetermined time period and a measuring device for measuring the change in rotation of the fan. A memory is preferably coupled to the power controller for storing a plurality of rotation values for providing a history of fan bearing performance. A current sensor or current limiter is preferably coupled in series with the fan, where the measuring device detects voltage pulses or poles of the fan. The power controller preferably includes a timer for determining the time period and a counter for counting rotation events. The power controller also preferably includes a control circuit for controlling a switch coupled between a power source and the fan. In a first embodiment, the power controller removes power from the fan for a relatively short period of time during normal operation while the fan is operating at a desired operating speed or energy level. In a second embodiment, the power controller activates the fan from a rest position and the measuring device measures the spin-up rotation of the fan. In a third embodiment, the power controller controls a variable power source for incrementally increasing the voltage applied to the fan during startup for determining a startup voltage.
106 Citations
14 Claims
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1. A fan test system for measuring the bearing friction of a fan receiving power from a power source during normal operation, comprising:
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a switch for coupling between the fan and the power source; a current limiter coupled in parallel with said switch; a power controller coupled to said switch to test the fan by controlling said switch to interrupt power to the fan for at least a predetermined time period; and a measuring device coupled to said current limiter for detecting voltage pulses of the fan to determine a spin-down rate value during said predetermined time period indicative of the bearing friction of the fan. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for determining the bearing friction of a fan during normal operation and for monitoring the fan over time, comprising the steps of:
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during operation, periodically disconnecting power from the fan for a predetermined time period; measuring a spin-down rate value for the fan during each predetermined time period to generate a plurality of spin-down rate values over time; and storing each of the plurality of spin-down rate values in a memory for establishing a history of bearing performance of the fan. - View Dependent Claims (9)
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10. A computer system, comprising:
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a fan for cooling the computer system during normal operation; a power source for providing operating power to said fan; a switch coupled to said fan for controlling power to said fan; a control circuit coupled to said switch for temporarily interrupting power to said fan for a predetermined period of time during normal operation of the computer system without substantially affecting the cooling function of said fan; and a fan speed measuring device coupled to said fan for measuring a rate value during said predetermined time period indicative of the spin-down rate of said fan. - View Dependent Claims (11, 12, 13, 14)
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Specification