HVAC fan-powered terminal unit having preset fan CFM
First Claim
1. A method of open loop operating a fan motor in a ventilation system to obtain a predetermined air flow rate, wherein an internal processor determines a pulse width of pulses of a pulse width modulated signal and controls said fan motor accordingly, said method comprising the steps of:
- generating a pulse width modulated signal having pulses with a substantially constant amplitude;
monitoring said pulse width modulated signal using a voltmeter measuring dc voltage; and
,adjusting said pulse width of said pulses of said pulse width modulated signal to obtain a preselected reading on said voltmeter, said preselected reading corresponding to said predetermined air flow rate.
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Accused Products
Abstract
An arrangement is disclosed for controlling fan motors in fan-powered terminal units which permit the air flow of the terminal units to be factory preset and reset using a voltmeter. The fan motor is responsive to the pulse width of pulses of a pulse width modulated signal to provide an air flow which is proportional to the pulse width. By adjusting the pulse width, the air flow may be set as desired. A pulse width modulated signal having pulses with a set amplitude and frequency is generated. The dc voltage of the pulse width modulated signal is measured using a voltmeter. As the pulses have a set amplitude and frequency, the pulse width of the pulses may be adjusted by controlling the dc voltage of the pulse width modulated signal. The fan motor is programmed to deliver the set air flow over a range of static pressures.
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Citations
32 Claims
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1. A method of open loop operating a fan motor in a ventilation system to obtain a predetermined air flow rate, wherein an internal processor determines a pulse width of pulses of a pulse width modulated signal and controls said fan motor accordingly, said method comprising the steps of:
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generating a pulse width modulated signal having pulses with a substantially constant amplitude; monitoring said pulse width modulated signal using a voltmeter measuring dc voltage; and
,adjusting said pulse width of said pulses of said pulse width modulated signal to obtain a preselected reading on said voltmeter, said preselected reading corresponding to said predetermined air flow rate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 14, 15, 16, 17)
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11. A method of open loop operating a fan motor in a ventilation system to obtain a predetermined air flow rate, wherein an internal processor determines a pulse width of pulses of a pulse width modulated signal and controls said fan motor accordingly, said method comprising the steps of:
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generating a pulse width modulated signal having pulses with a substantially constant amplitude; measuring a voltage of said pulse width modulated signal using a voltmeter measuring a dc voltage; and adjusting said pulse width of said pulses of said pulse width modulated signal to obtain a preselected reading on said voltmeter, said preselected reading corresponding to said predetermined air flow rate. - View Dependent Claims (12, 13, 18, 19)
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20. An open loop method of presetting the air flow generated by a fan motor for a ventilation system for operation within a range of static pressures, said method comprising the steps of:
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providing a fan motor having an internal processor to determine a pulse width of pulses of a pulse width modulated signal and to control said fan motor accordingly, said pulse width corresponding to the air flow provided by said fan motor; generating said pulse width modulated signal to have pulses with a substantially constant amplitude; and setting the air flow provided by said fan motor by adjusting said pulse width of said pulses to obtain a preselected reading on a voltmeter measuring dc voltage, said preselected reading corresponding to the air flow, such that the air flow provided by said fan motor is set for static pressures within said range. - View Dependent Claims (21)
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22. An apparatus for circulating air in a ventilation system, said apparatus comprising:
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a fan motor having an internal processor to determine a pulse width of pulses of a pulse width modulated signal and to control said fan motor accordingly, said fan motor providing a predetermined air flow rate corresponding to said pulse width in an open loop manner; and a controller generating said pulses of said pulse width modulated signal, said pulses having a substantially constant amplitude such that said predetermined air flow rate may be obtained by monitoring said pulse width modulated signal with a voltmeter measuring dc voltage to obtain a preselected reading on said voltmeter, said preselected reading corresponding to said predetermined air flow rate. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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Specification