Gas furnace with variable speed draft inducer

• US 6,377,426 B2
• Filed: 07/03/2001
• Issued: 04/23/2002
• Est. Priority Date: 12/21/1998
• Status: Expired due to Term

• Current Assignee: Trane International Inc. (Trane Technologies plc)
• Original Assignee: American Standard International Inc (Trane Technologies plc)
• Inventors: Storm, Timothy W., Holmes, Leonard W., Vershaw, James T., Hugghins, G. Jeffrey, Helt, Robert W.
• Primary Examiner(s): HUYNH, KIM NGOC
• Application Number:
  US09/898,344
• Publication Number:
  US 20010044084A1
• Time in Patent Office: 294 Days
• Field of Search: 361/23, 361/24, 361/22, 361/78, 361/79, 431/75-78, 431/18, 431/12, 431/87, 318/798-800, 310/62-65, 126/116.A
• US Class Current: 361/23
• CPC Class Codes: F23N 2223/48 Learning / Adaptive control
• CPC Class Codes: F23N 2225/04 pressure
• CPC Class Codes: F23N 2225/13 outdoor temperature
• CPC Class Codes: F23N 2227/16 Checking components, e.g. electronic
• CPC Class Codes: F23N 2227/20 Calibrating devices
• CPC Class Codes: F23N 2233/00 Ventilators
• CPC Class Codes: F23N 2233/04 with variable speed
• CPC Class Codes: F23N 3/082 using electronic means
• CPC Class Codes: F23N 5/20 with a time programme acting through electrical means, e.g. using time-delay relays
• CPC Class Codes: F23N 5/24 Preventing development of abnormal or undesired conditions, i.e. safety arrangements F23N5/02 - F23N5/18 take precedence

Abstract

A method of controlling a variable speed draft inducer motor and fan in a gas furnace. The method comprises the steps of: detecting a first fault driving the motor to a maximum operating range; detecting a second fault forcing the motor to operate towards a minimum operating range; and generating a fault signal if both faults are detected substantially simultaneously.

Claims

1. A method of ensuring proper operation of a motor comprising the steps of:

detecting a first fault driving the motor to a maximum operating range;

detecting a second fault forcing the motor to operate towards a minimum operating range; and

generating a fault signal if both faults are detected substantially simultaneously.

2. The method of claim 1 wherein the fault generating signal includes the further step of terminating the generation of a status signal.

3. The method of claim 1 wherein the second fault is detected based upon a bearing drag measurement using a torque/speed relationship.

4. The method of claim 1 wherein the second fault is detected based on a restriction in the exhaust vent.

5. The method of claim 1 wherein the status signal is off based on an invalid input or a minimum operating range detection for the motor, wherein the status signal is pulsed during normal operation, and wherein the status signal is on continuously if the maximum operating range of the motor is detected.